Original Article 373
Author
A. A. Farag
Affiliation
Department of Chemistry, Faculty of Science (Girl’s), Al-Azhar University, Nasr City, Cairo, Egypt
Key words ▶ thiosemicarbazones ● ▶ thiosemicarbazide ● ▶ antibacterial and antifungal ● activities
Abstract
▼
This article describes the synthesis of novel 5-(morpholinosulfonyl)isatin derivatives having biologically active thiazole moiety were synthesized via 2 synthetic routes. The first route involved interaction of 5-(morpholino-sulfonyl) isatin with aminothiazole derivatives to give the Schiff’s base derivatives (2, 3). The second route involved preparation of thiosemicarbazones (4–7) by treatment of 5-(morpholino- sulfonyl)
Introduction
▼
received 13.03.2014 accepted 02.07.2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1384609 Published online: August 12, 2014 Drug Res 2015; 65: 373–379 © Georg Thieme Verlag KG Stuttgart · New York ISSN 2194-9379 Correspondence A. A. Farag Department of Chemistry Faculty of Science (Girl’s) Al-Azhar University PO box 11754 Yousef Abbas Str., Nasr City Cairo Egypt Tel.: + 20/233/335 929 Fax: + 20/233/370 931 [email protected]
Despite many significant progresses in antimicrobial therapy, infectious diseases caused by bacteria and fungi remain a major worldwide health problem due to rapid development of resistance to the existing antimicrobial drugs. So, the medical community faces a serious problem against infections caused by the pathogen microbes and needs an effective therapy and search for novel antimicrobial agents [1–4]. Various derivatives of isatin are known to possess a range of pharmacological properties. In recent years, isatin derivatives are reported to exhibit broad spectrum chemotherapeutic properties such as antiviral [5], anti-TB [6], antifungal, and antibacterial activities [7]. Investigation of the structure activity relationships in isatin derivatives revealed that 5-halogenation, and 3-thiosemicarbazone formation was effective in causing a marked rise in activity against various bacteria, fungi and virus [5–7]. In addition, cyclization of isatin-3-thisemicarbazones to 4-thiazoline, and 4-thiazolidinone, was efficient in increasing antimicrobial activity [5]. There has been a considerable interest in the chemistry of thiazole ring system, which is a core structure in various synthetic pharmaceuticals displaying a broad spectrum of biological activities [8–11].
isatin with thiosemicarbazides followed by cycloalkylation of the products with halogenated compounds to give the thiazole derivatives (8–19). Most of the synthesized compounds were screened against Gram (+), Gram (−) bacterial and fungi. The best gram positive activity was displayed by compounds 1, 13, 14, 15, 16 and 18 and the best gram negative bacteria was showed by compounds 1, 12, 13, 15, and 19, whereas compounds 1, 12, 13, 15, and 19 exhibited the best antifungal activity.
Literature survey reveals that morpholine ring is important for antimicrobial activity [12]. As a part of our extensive research program to rapidly assemble novel bioactive compounds under mild conditions [13, 14] and the aforementioned microbial inhibitory activities of isatin derivatives prompted us to attach sulfonylmorpholinyl isatin to the 4-thiazolidinone scaffold. The combination of 2 privileged structures in one molecule leads to drug-like molecules, also to study the effect of the substituent on the activities and make a comparative study to deduce a structure activity relationship.
Experimental Section
▼
All melting points were determined on an electrothermal Gallenkamp apparatus and are uncorrected. The IR spectra were measured on a Mattson 5 000 FT-IR Spectrometer in potassium bromide discs. The NMR spectra were recorded in DMSO-d6 on a Bruker WP spectrometer (500 MHz) and the chemical shifts δ downfield from TMS as an internal standard. The mass spectra were recorded on Finnegan MAT 212 instrument, the ionizing voltage was 70 ev. Elemental analyses were carried out by the Microanalytical unit of Faculty of Science, Cairo
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
Synthesis and Antimicrobial Activity of 5-(morpholino sulfonyl)isatin Derivatives Incorporating a Thiazole Moiety
374 Original Article
5-(Morpholin-4-ylsulfonyl)-1H-indole-2,3-dione (1)
5-(Morpholinosulfonyl)isatin (1) was synthesized according to reported paper [15], orange crystals; yield 86 %; mp 176–177 ℃; IR: ν/cm − 1: 3 315 (NH) and 1 757 (C = O); 1H NMR: δ/ppm = 2.88 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.63 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.13 (d, 1H, J = 8.2 Hz, indole-H), 7.69 (m, 1H, indole-H), 7.91 (m, 1H, indole-H ), 11.49 (s, 1H, NH, D2O-exchangeable); 13C NMR: 46.3 (2 × CH2), 65.8 (2 × CH2), 113.4, 118.6, 123.9, 129.7, 137.6, 154.5, 159.8(C = O), 183.4 (C = O); Anal. Calcd for C12H12N2O5S (296.30): C, 48.64; H, 4.08; N, 9.45; Found: C, 48.42; H, 4.11; N, 9.63.
Synthesis of Schiff’s bases 2,3
A mixture of isatin 1 (0.01 mol) and the requisite amine (namely, 2-aminothiazole, 3-amino-2-thioxothiazolidin-4-one) (0.01 mol) in acetic acid (50 mL) was heated under reflux for 2 h. The reaction mixture was concentrated and the residue was allowed to come to ambient temperature. The solid product was filtered and recrystallized from dioxane to give 2 and 3, respectively.
5-(Morpholinosulfonyl)-3-(thiazol-2-ylimino)indolin-2one (2)
Reddish brown crystals; yield 84 %; mp 234–235 ℃; IR: υ/ cm − 1 = 3 390 (NH) and 1 701 (C = O); 1H NMR: δ/ppm = 2.86 (t, 4H, J = 4.1 Hz, 2 × CH2), 3.83 (t, 4H, J = 4.0 Hz, 2 × CH2), 7.15–7.98 (m, 5H, Ar-H and thiazole H4, 5), 11.55 (s, 1H, NH, D2O-exchangeable); Anal. Calcd for C15H14N4O4S2 (378.43): C, 47.61; H, 3.73; N, 14.81; Found: C, 47.78; H, 3.52; N, 14.98.
3-(5-(Morpholinosulfonyl)-2-oxoindolin-3ylideneamino)-2-thioxothiazolidin-4-one (3)
Reddish brown crystals; yield 85 %; mp > 300 ℃; IR: υ/ cm − 1 = IR: ν/cm − 1: 3 317, 3 233 (NH) and 1 699 (C = O); 1HNMR: δ/ppm: 2.91 (d, 4H, J = 4.0 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.0 (s, 2H, CH2), 7.20 (d, 1H, J = 8.0 Hz, indole-H), 7.80 (d, 1H, J = 8.4 Hz, indole-H), 9.26 (s, 1H, indole-H), 11.78 (s, 1H, 1NH, D2Oexchangeable); MS, m/z ( %): 426 (M + ; 12.9), 277 (19.3), 174 (13.5), 86 (100); Anal. Calcd for C15H14N4O5S3 (426.49): C, 42.24; H, 3.31; N, 13.14; Found: C, 42.45; H, 3.21; N, 13.35.
Synthesis of thiosemicarbazone derivatives 4–7
The mixture of 5-(morpholinosulfonyl) isatin (1) (0.01 mol) and the desired thiosemicarbazide derivative (namely thiosemicarbazide, N-(methyl)thiosemicarbazide, N-(ethyl)thiosemicarbazide, N-(phenyl)thiosemicarbazide) (0.01 mol) in acetic acid (50 mL) was heated under reflux for 0.5 h. the reaction mixture was allowed to come to ambient temperature. The resultant solid product so precipitated was collected, and crystallized from dioxane to give the desired thiosemicarbazones 4–7.
2-(5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazinecarbothioamide (4)
Yellow crystals; yield 92 %; mp 222 ℃; IR: ν/cm − 1: 3 417, 3 232, 3 145 (NH, NH2) and 1 704 (C = O). 1HNMR: δ/ppm: 2.93 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.22 (d, 1H, J = 8.0 Hz, indole-H), 7.77 (d, 1H, J = 8.4 Hz, indole-H), 8.16 (s, 1H, indole-H), 9.21 (s, 2H, NH2, D2O-exchangeable); 11.65, 12.33 (2 s, 2H, 2NH, D2O-exchangeable); 13C NMR: 46.4 (2 × CH2), 65.7 (2 × CH2), 111.8, 120.9, 121.4, 128.5, 130.9, 131.2, 146.4 (C = N), 163.2 (C = O), 179.3 (C = S); MS, m/z ( %): 369 (M + ; 93.5), 368 Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
(73.0), 243 (12.5), 229 (89.1), 155 (94.7), 145 (24.0), 140 Anal. Calcd for C13H15N5O4S2 (369.42): C, 42.27; H, 4.09; N, 18.96; Found: C, 42.33; H, 4.12; N, 18.88.
N-Methyl-2-(5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazinecarbothio-amide (5)
Yellow crystals; yield 87 %; mp 271–273 ℃; IR: ν/cm − 1: 3 400, 3 249 (NH) and 1 711 (C = O); 1HNMR: δ/ppm: 2.92 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.02 (d, 3H, J = 4.5 Hz, NHCH3), 3.73 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.00 (br, 1H, NHCH3, D2O-exchangable), 7.24 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.17 (s, 1H, indole-H); 11.65, 11.8 (2 s, 2H, 2NH, D2O-exchangeable); 13 C NMR: 31.8 (CH3), 46.3 (2 × CH2), 65.8 (2 × CH2), 111.8, 120.5, 121.4, 129.4, 130.5, 131.0, 146.2 (C = N), 163.1 (C = O), 178.4 (C = S); Anal. Calcd for C14H17N5O4S2 (383.45): C, 43.85; H, 4.47; N, 18.26; Found: C, 43.77; H, 4.52; N, 18.54.
N-Ethyl-2-(5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazinecarbothio-amide (6)
Yellow crystals; yield 92 %; mp 243–245 ℃; IR: υ/cm − 1 = 3 382, 3 288 (NH), 1 709 (C = O); 1H NMR: δ/ppm = 1.21 (t, 3H, J = 6.85 Hz, CH3), 2.88 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.65 (m, 6H, 3 × CH2), 7.16 (d, 1H, J = 8.0 Hz, indole-H), 7.72 (d, 1H, J = 8.4 Hz, indole-H), 8.05 (s, 1H, indole-H), 9.55, 11.20, 12.26 9.55(t,1H, 1NH, D2O-exchangable) and 11.20, 12.26 (2 s, 2H, 2NH, D2O-exchangable); 13C NMR: 14.4 (CH3), 39.3 (CH2), 46.4 (2 × CH2), 65.7 (2 × CH2), 111.9, 120.6, 121.8, 128.2, 130.7, 131.2, 147.0 (C = N), 163.2 (C = O), 178.4 (C = S); MS, m/z ( %): 397 (M + ; 15.3), 369 (33.5), 296 (19.5), 131 (17.1), 103 (45.5), 89 (100); Anal. Calcd for C15H19N5O4S2 (397.47): C, 45.33; H, 4.82; N, 17.62; Found: C, 45.21; H, 4.72; N, 17.82.
2-(5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene)-Nphenylhydrazinecarbothioamide (7)
Yellow crystals; yield 79 %; mp 254–255 ℃; 3 387, 3 276 (NH) and 1 706 (C = O); 1HNMR: δ/ppm: 2.92 (t, 4H, J = 4.1 Hz, 2CH2), 3.73 (t, 4H, J = 4.2 Hz, 2CH2), 6.93–7.65 (m, 6H, Ar-H), 7.75 (d, 1H, J = 8.4 Hz, indole-H), 8.19 (s, 1H, indole-H), 10.81, 11.22, 12.67 (3 s, 3H, 3NH, D2O-exchangeable); 13C NMR: 46.4 (2 × CH2), 65.9 (2 × CH2), 111.9, 121.1, 121.3, 126.4 (2H), 126.7, 128.8 (2H), 129.5, 131.1, 131.4, 138.9, 146.5 (C = N), 163.2 (C = O), 177.3 (C = S); Anal. Calcd for C19H19N5O4S2 (445.52): C, 51.22; H, 4.30; N, 15.72; Found: C, 51.41; H, 4.43; N, 15.88.
Synthesis of Thiazole Derivatives
▼
A mixture of the thiosemicarbazide derivatives 4–7 (0.01 mol), ethyl chloroacetate, ethyl 2-chloropropanoate or chloroacetone (0.01 mol) and fused sodium acetate (0.02 mol) in acetic acid (50 mL) was heated under reflux for 6 h. The reaction mixture was allowed to come to ambient temperature. The obtained product was collected by filtration and recrystallized from the appropriate solvent to give 8–11, 12–15 and 16–19, respectively.
2-((5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazono)thiazolidin-4-one (8)
Reddish brown crystals; yield 79 %; mp 254–255 ℃; IR: ν/cm − 1: 3 399, 3 287 (NH) and 1 698 (C = O); 1H NMR: δ/ppm = 2.82 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.69 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.13 (s, 2H, CH2), 7.17 (d, 1H, J = 8.0, indole-H), 7.75 (d, 1H, J = 8.4, indole-H), 8.54 (s, 1H, indole-H), 11.53, 12.13 (2 s, 2H, 2NH, D2O-exchangeable);
Downloaded by: University of Georgia Libraries. Copyrighted material.
University. Antimicrobial screening was carried out in Regional Center for fungi and its applications in Al-Azher University.
Original Article 375
3-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin3ylidene)hydrazono)thiazolidin-4-one (9)
Reddish crystals; yield 79 %; mp 258–260 ℃; IR: ν/cm − 1: 3 303 (NH), 1 707(C = O); 1H NMR: δ/ppm = 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.19 (3H, s, CH3), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.11 (s, 2H, CH2), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.41(s, 1H, NH, D2O-exchangeable); 13C NMR: 30.0 (CH3), 33.1 (CH2), 46.4 (2 × CH2), 65.9 (2 × CH2), 111.4, 117.6, 128.0, 128.7, 132.9, 147.9, 148.4, 165.2 (C = N), 172.8 (C = O), 174.4 (C = O); Anal. Calcd for C16H17N5O5S2 (423.47): C, 45.38; H, 4.05; N, 16.54; Found: C, 45.46; H, 4.26; N, 16.74.
3-Ethyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)thiazolidin-4-one (10)
117.6, 128.0, 128.7, 132.9, 147.9, 148.4, 158.6 (C = N), 172.8 (C = O), 176.3 (C = O); MS, m/z ( %): 437 (M + ; 5.9), 308 (31.4), 260 (28.5), 219 (21.3), 159 (16), 92 (100); Anal. Calcd for C17H19N5O5S2 (437.49): C, 46.67; H, 4.38; N, 16.01; Found: C, 46.78; H, 4.23; N, 16.26.
3-Ethyl-5-methyl-2-((5-(morpholinosulfonyl)-2oxoindolin-3-ylidene)hydrazono) thiazolidin-4-one (14)
Reddish brown crystals; yield 92 %; mp 241–242 ℃; IR: ν/cm − 1: 3 327 (NH) and 1 707 (C = O); 1H NMR: δ/ppm = 1H NMR: δ/ ppm = 1.55 (d, 3H, CH3), 3.06 (s, 3H, NCH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 3.88 (q, 2H, CH2), 4.38 (q, 1H, CH), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.62 (s, 1H, NH, D2Oexchangeable); Anal. Calcd for C18H21N5O5S2 (451.52): C, 47.88; H, 4.69; N, 15.51; Found: C, 47.93; H, 4.51; N, 15.67.
5-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)-3-phenyl- thiazolidin-4-one (15)
Reddish brown crystals; yield 79 %; mp 250–252 ℃; IR: υ/ cm − 1 = 3 447(NH), 1 732 (C = O); 1H NMR: δ/ppm = 1.28 (t, 3H, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 3.88 (q, 2H, CH2), 4.11 (s, 2H, CH2), 7.15 (d, 1H, J = 8.0 Hz, indoleH), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.62 (s, 1H, NH, D2O-exchangeable); 13C NMR: 12.5 (CH3), 33.3 (CH2), 38.90 (CH2), 46.3 (2 × CH2), 65.7 (2 × CH2), 111.5, 117.5, 127.8 (3C), 133.1, 147.7 (C = N), 148.5 (C = N), 165.2 (C = O), 174.3 (C = O); Anal. Calcd for C17H19N5O5S2 (437.49): C, 46.67; H, 4.38; N, 16.01; Found: C, 46.46; H, 4.22; N, 16.17.
Brown powder; yield 92 %; mp 247–246 ℃; IR: υ/cm − 1 = 3 296 (NH), 1 756, 1 699 (C = O); 1H NMR: δ/ppm = 1.66 (d, 3H, CH3), 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 4.48 (q, 1H, CH), 7.00–8.05 (m, 8H, Ar-H), 11.26 (br, 1H, NH, D2Oexchangeable); 13C NMR: 19.8 (CH3), 42.1 (CH), 46.4 (2 × CH2), 67.02 (2 × CH2), 111.9, 121.1, 121.3, 126.4 (2H), 126.7, 128.8 (2H), 129.5, 131.1, 131.4, 138.9, 146.5 (C = N), 163.2 (C = O); Anal. Calcd for C22H21N5O5S2 (499.56): C, 52.89; H, 4.24; N, 14.02; Found: C, 53.08; H, 4.11; N, 14.30.
2-((5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazono)-3-phenylthiazo- lidin 4-one (11)
3-((4-Methylthiazol-2(3H)-ylidene)hydrazono)-5(morpholinosulfonyl)indolin-2-one (16)
Brownish crystals; yield 79 %; mp 254–255 ℃; IR: υ/cm − 1 = 3 310 (NH), 1 709 (C = O); 1H NMR: δ/ppm = 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 4.46 (s, 2H, CH2), 7.00– 8.05 (m, 8H, Ar-H), 11.26 (br, 1H, NH, D2O-exchangeable); Anal. Calcd for C21H19N5O5S2 (485.45): C, 51.95; H, 3.94; N, 14.42; Found: C, 52.18; H, 4.08; N, 14.66.
5-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)thiazolid- in-4-one (12)
Reddish brown crystals; yield 92 %; mp 243–245 ℃; IR: ν/cm − 1: 3 398, 3 287 (2NH) and 1 698 (C = O); 1H NMR: δ/ppm = 1.52 (d, 3H, J = 9 Hz, CH3), 2.82 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.69 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.33 (q, 1H, J = 9 Hz, CH), 7.17 (d, 1H, J = 8.0, indole-H), 7.75 (d, 1H, J = 8.4 Hz, indole-H), 8.54 (s, 1H, indole-H), 11.92, 12.13 (2 s, 2H, 2NH, D2O-exchangeable); 13C NMR: 19.78 (CH3), 45.13 (CH), 158.61 (N = C), 176.30 (NC = O). 12.5 (CH3), 33.3 (CH2), 38.90 (CH2), 46.3 (2 × CH2), 65.7 (2 × CH2), 111.5, 117.5, 127.8 (3C), 133.1, 147.7 (C = N), 148.5 (C = N), 165.2 (C = O), 174.3 (C = O); MS, m/z ( %): 423 (M + ; 1.7), 367 (4.0), 57 (100), Anal. Calcd for C16H17N5O5S2 (423.47): C, 45.38; H, 4.05; N, 16.54; Found: C, 45.45; H, 4.01; N, 16.67.
3,5-Dimethyl-2-((5-(morpholinosulfonyl)-2-oxoindolin3-ylidene)hydrazono)-thiazo lidin-4-one (13)
Reddish brown crystals; yield 92 %; mp 240–242 ℃; IR: ν/cm − 1: 3 355 (NH) and 1 704 (C = O); 1H NMR: δ/ppm = 1.55 (d, 3H, J = 9 Hz, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.06 (s, 3H, NCH3), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.38 (q, 1H, J = 9 Hz, CH), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4, indole-H), 8.51 (s, 1H, indole-H), 11.41(s, 1H, NH, D2O-exchangeable); 13C NMR: 19.7 (CH3), 31.2 (CH3), 45.1 (CH), 46.4 (2 × CH2), 65.9 (2 × CH2), 111.4,
Brown crystals, yield 79 %; mp 254–255 ℃; IR: υ/cm − 1 = 3 390 (NH) and 1 701(C = O); 1H NMR: δ/ppm = 2.33 (s, 3H, CH3), 2.85 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.61 (s, 1H, thiazole), 7.09 (d, 1H, J = 8.0, indole-H), 7.61 (d, 1H, J = 8.4 Hz, indole-H), 8.58 (s, 1H, indole-H), 11.02, 11.8 (2 s, 2H, 2NH, D2Oexchangeable); 13C NMR: 14.3 (CH3), 46.4 (2 × CH2), 65.9 (2 × CH2), 102.6, 110.1, 111.8, 118.7, 125.2, 127.9, 130.3, 136.8, 145.7 (C = N), 166.2 (C = O, 179.4 (C = O); Anal. Calcd for C16H17N5O4S2 (407.47): C, 47.16; H, 4.21; N, 17.19; Found: C, 47.44; H, 4.01; N, 17.34.
3-((3,4-Dimethylthiazol-2(3H)-ylidene)hydrazono)-5(morpholinosulfonyl)indolin-2-one (17)
Reddish crystals; yield 73 %; m.p. 297–298 ℃; IR: ν/cm − 1: 3 334 (NH), 1 700 (C = O); 1H NMR: δ/ppm = 1.79 (s, 3H, CH3), 2.74 (s, 3H, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.67 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.63 (s, 1H, thiazole), 7.11 (d, 1H, J = 8.0 Hz, indole-H), 7.64 (d, 1H, J = 8.4 Hz, indole-H), 8.59 (s, 1H, indole-H), 11.13 (s, 1H, NH, D2O-exchangeable); 13C NMR: 21.4 (CH3), 32.7 (CH3), 46.4 (2 × CH2), 65.8 (2 × CH2), 101.9, 110.2, 118.6, 125.7, 127.9, 130.0, 138.4, 145.9, 166.1, 172.1, 176.9; Anal. Calcd for C17H19N5O4S2 (421.49): C, 48.44; H, 4.54; N, 16.62; Found: C, 48.56; H, 4.36; N, 16.51.
3-((3-Ethyl-4-methylthiazol-2(3H)-ylidene)hydrazono)5-(morpholinosulfonyl)indolin-2-one (18)
Reddish brown powder; yield 65 %; m.p. 276–277 ℃; IR: ν/cm − 1: 3 430 (NH) and 1 700(C = O); 1H NMR: δ/ppm = 1.37 (t, 3H, CH3), 2.33 (s, 3H, CH3), 2.85 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.14 (q, 2H, CH2), 6.61 (s, 1H, thiazole), 7.09 (d, 1H, J = 8.0 Hz, indole-H), 7.61(d, 1H, J = 8.4 Hz, indole-H), 8.58 Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
Anal. Calcd for C15H15N5O5S2 (409.44): C, 44.00; H, 3.69; N, 17.10; Found: C, 44.12; H, 3.84; N, 17.23.
(s, 1H, indole-H), 11.02 (s, 1H, NH, D2O-exchangeable); 13C NMR: 13.3 (CH3), 13.7 (CH3), 40.6 (CH2), 46.4 (2 × CH2), 65.7 (2 × CH2), 102.6, 110.3, 118.6, 125.5, 127.0, 130.3, 137.8, 138.2, 145.9, 166.1, 176.3; MS, m/z ( %): 435 (M + ; 80.9), 322 (23.1), 230 (20.3), 173 (19.8) 139 (61.6), 128 (60.1), 114 (100); Anal. Calcd for C18H21N5O4S2 (435.52): C, 49.64; H, 4.86; N, 16.08; Found: C, 49.84; H, 4.77; N, 16.23.
functions, and at 1 704 cm − 1 due to C = O function. The “1H NMR” spectrum revealed 2 broad singlet signals at δ = 9.21 ppm assignable to NH2 protons, 2 singlet signals at δ = 11.65, 12.33 ppm characteristic to 2NH protons. 13C NMR showed signals at 46.4 corresponding to N(CH2)2 and at 64.7 attributed to O(CH2)2. The mass spectrum showed a molecular ion peak (M + ) at m/z = 369 (93.5) corresponding to a molecular formula C13H15N5O4S2. We have extended our synthetic program to utilize structure 4–7 as the key starting materials for cycloalkylation on the hope of obtaining thiazole derivatives with better biological activity. When thiosemicarbazones 4–7 were reacted with ethyl chloroacetate, the corresponding thiazolidine derivatives 8–11 were obtained. Elemental analyses and spectral data were in favor of these proposed thiazole structure. The IR spectrum of 10 showed absorption bands at 3 447 and 1 732 cm − 1 due to NH and C = O groups, respectively. The “1H NMR” spectrum showed a triplet signal in the region at 4.11 ppm corresponding to the CH3 protons together with a quartet and singlet signals at 3.88, 4.11 ppm corresponding to CH2 ethyl and CH2 thiazole protons. Similarly, the novel thiazolidinone 12–15 could be achieved via the reaction of 4–7 with ethyl 2-chloropropanoate. The structure of the prepared compounds was elucidated on the basis of elemental analyses and spectral data. In addition, treatment 4–7 with chloroacetone furnished the corresponding thiazole derivatives 16– 19. The thiazoles 16–19 were assigned for the reaction product on the basis of their elemental analyses and spectral data. The IR spectrum of 19 revealed absorption bands at 3 380 and 1 729 cm − 1 characteristic NH and C = O functions, respectively. The “1H NMR” spectrum of 19 exhibited signals at 1.94, 2.93, 3.59 and 6.73 ppm assignable to CH3, 2 morpholinyl 2CH2 and thiazole H-5 protons, respectively. Moreover, its 13CNMR spectrum revealed 23 carbons, the most important signals are 14.8, 46.1, 65.6, 165.9 and 178.5 which are characteristics for CH3, N(CH2)2, O(CH2)2, C = N, carbonyl carbons, respectively.
3-((4-Methyl-3-phenylthiazol-2(3H)-ylidene) hydrazono)-5-(morpholinosulfonyl)- indolin-2-one (19)
Brownish crystals; yield 72 %; m.p. 265–267 ℃; IR: υ/cm − 1 = 3 380 (NH), 1 729 (C = O); 1H NMR: δ/ppm = 1.94 (s, 3H, CH3), 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.59 (t, 4H, J = 4.3 Hz, 2 × CH2), 6.73 (s, 1H, CH-thiazole), 7.00 (d, 1H, J = 8.0 Hz, indole-H), 7.45–7.60 (m, 6H, Ar-H), 7.74 (s, 1H, indole-H), 10.59 (s, 1H, NH, D2O-exchangeable); 13C NMR: 14.8 (CH3), 46.1 (2CH2), 65.6 (2CH2), 103.0, 110.1, 118.0, 125.3, 126.9, 128.2 (2C), 129.8, 130.3 (2C), 130.9, 136.6, 137.7, 138.8, 146.0, 165.9, 178.5; Anal. Calcd for C22H21N5O4S2 (483.56): C, 54.64; H, 4.38; N, 14.48; Found: C, 54.78; H, 4.18; N, 14.67.
Results and Discussion
▼
The synthetic strategies adopted for the synthesis of the intermediates and target compounds are depicted in ● ▶ Fig. 1, 2. The reactivity of 5-(morpholinosulfonyl)isatin (1) [13] towards some different aminothiazole derivatives was studied with the objective of obtaining biologically active compounds. Thus, reaction of 1 with 2-aminothiazole or 3-amino-2-thioxothiazolidin4-one afforded the corresponding thiazoleimino derivatives 2 and 3. The structures of 2 and 3 have been assigned as a reaction product on the basis of analytical and spectral data. The IR spectrum of 3 displayed absorption bands at 3 317, 3 233 (NH) cm − 1 due to NH function and at 1 699 cm − 1 corresponding to C = O function. The “1H NMR” spectrum exhibited a singlet signal at δ = 6.0 ppm assignable to thiazolidine-CH2 protons, another 2 triplet signals at δ = 2.91 and 3.65 ppm specific for morpholinyl protons and a singlet signal at δ = 11.78 ppm due to NH proton. The behaviour of the 1 towards some thiosemicarbazides to obtain polyfunctionally substituted thiazole moiety of potential pharmaceutical interest, has been investigated. 5-morpholinosulfonyl isatin was reacted with thiosemicarbazide derivatives in acetic acid under reflux condition, a product that was identified as 5-morpholinosulfonylisatin-3-thiosemicar- bazones 4–7. The structure was assigned on the basis of the elemental analyses and spectral data. The IR spectrum of 4 showed absorption bands at 3 417, 3 232, 3 145 cm − 1 corresponding to NH and NH2 N H2N
O
S
N
S
Antibacterial and Antifungal Activities
▼
Most of the newly synthesized target compounds were evaluated for their in vitro antimicrobial activities against the human pathogens Staphylococcus aureus (RCMB 010027), Staphylococcus epidermidis (RCMB 010024), Streptococcus pyogenes (RCMB 010015) and Bacillis subtilis (RCMB 010063) as examples of Gram-positive bacteria and Proteous vulgaris (RCMB 010085), Klebsiella pneumonia (RCMB 010093), Shigella flexneri (RCMB 0100542) and Pseudomonas aeruginosa (RCMB 010043) as examples of Gram-negative bacteria. They were also evaluated for their potential antifungal activities against the following
N S
O
2 O N
S
O
Fig. 1 Synthesis of Schiff’s bases derivatives.
N
O
N H
O
O S
O
1
N H
O
H2N
N
S
S O
O
N
S
O
N
O
3
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
N H
O
N O
S
Downloaded by: University of Georgia Libraries. Copyrighted material.
376 Original Article
Original Article 377
O O S N
O
1
N H
O
O O S N
ClCH2COOEt
RNHCSNHNH2 O N
S
O
N H 8-11
S
O
N
O 4-7
N H
N H
NHR
O Cl
O
OC2H5
O
CH3
N O
O
ClCH2COCH3
N
S
O
O
N N N H 16-19
O
R N
N N
CH3
S
O
R N
O
S
O
N N N O H 12-15
R N S
O CH3
S 4,8,12,16 R = H 5,9,13,17 R = CH3 6,10,14,18 R = C2H5 7,11,15,19 R = C6H5
Fig. 2 Synthesis of thiosemicarbazone and thiazole derivatives.
fungal strains; Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593), Candida albicans (RCMB 05035) and Geotricum candidum (RCMB 05096). Agar-diffusion method was used for the determination of the preliminary screening of antibacterial and antifungal activities. Ampicillin and amphotricin B were used as reference drugs. The results were recorded for each tested compound as the average diameter of inhibition zones of ▶ Table 1). bacterial or fungal growth around the discs in mm ( ● Certain aspects of the structure activity relationships for these compounds can be more clearly highlighted. The substitution at 3-position was referred by X. Compound No. 1, the X = O resulted in the highest antimicrobial activity among all the compounds investigated in this study. 5-(morpholinosulfonyl)isatin exhibited the highest antibacterial activity against most of the organisms and showed results greater than the reference drug. Compound 3, the × group have 2-thioxo-thiazolidin-4-one moiety; introduction of 2-thioxo-thiazolidin-4-one moiety had a detrimental effect on antibacterial activity, 3 showed moderate activities against the tested bacteria. Compounds 4, 6 the × group N-substituted thiosemicarbazone side chain moiety (4; H, 6 C2H5): Regarding the effect of N-substituted, it is evident that: It was noticed that the presence ethyl group (6) displayed detrimental effect on the antimicrobial activity. Compounds 9–11, the × group have hydrazono side chain ending with N-substituted thiazolidine moiety (9; CH3, 10; C2H5, 11; Ph): Regarding the effect of N-substituted, it is evident that: It was noticed that the presence ethyl group (10) at the thiazole ring displayed detrimental effect on the antimicrobial activity. The presence of phenyl moiety (11) resulted in the highest antimicrobial activity among this series. Compounds 12–15, the × group have hydrazono side chain ending with N-substituted thiazolidine moiety (12; H, 13; CH3, 14; C2H5, 15; Ph): Regarding the effect of N-substituted, it is evident that: the type of the substitutions on the thiazole moiety nearly does not have effect on antimicrobial
activity. The presence of phenyl moiety (15) resulted in the highest antimicrobial activity among this series. Compounds 16–19, the × group have hydrazono side chain ending with N-substituted thiazole moiety (16; H, 17; CH3, 18; C2H5, 19; Ph): Regarding the effect of N-substituted, it is evident that varying such a unit may have a dramatic effect on antimicrobial activity, which may be augmented or reduced depending on whether a matching or mismatching relationship exists with the N-substituted. The type of the substitutions on the thiazole moiety is important. It was noticed that the presence alkyl groups such as methyl and ethyl at the thiazole ring displayed detrimental effect on the antimicrobial activity. The presence of phenyl moiety (19) resulted in the highest antimicrobial activity among all the compounds investigated in this series. N- phenyl moiety exhibited activities near to the references drug.
MIC of the most Active Compounds
▼
The minimal inhibitory concentrations (MICs) for compounds that showed significant growth inhibition zones were determined. The synthesized compounds 1, 11, 13–16, 19 and reference drugs was then evaluated in vitro using the twofold serial dilution technique. The lowest concentration showing no growth was taken as the minimum inhibitory concentration (MIC). The results of minimum inhibitory concentration were reported in ● ▶ Table 2. Among this series, 5-(morpholinosulfonyl)isatin (1) showed highly inhibitory activity against all the screened bacteria when compared with ampicillin as revealed from their MIC values (0.007–0.49 μg/mL) and most of cases compound 1 was exhibited significant antibacterial activity more than Ampicillin. Regarding the activity of 1 against fungal strains, Compound 1 showed fourfold potency of amphotricin B in inhibiting the Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
O
378 Original Article
Table 1 Antibacterial activity of the synthesized compounds against the pathological organisms expressed as inhibition diameter zones in millimeters (mm) based on well diffusion assay. Gram − ve
Gram + ve
Fungi
No.
S. a.
S. e.
S. p.
B. s.
P. v.
K. p.
S. f.
P. a.
A. f.
A c.
G. c.
C. a.
1 3 4 6 9 10 11 12 13 14 15 16 17 18 19 Stand.
29.3 12.6 14.6 11.3 16.9 10.6 19.6 20.9 20.6 20.6 26.3 22.3 15.3 17.6 25.3 28.9
25.3 11.7 16.2 12.4 19.3 9.3 20.3 19.3 23.4 22.4 24.2 20.6 14.6 14.2 22.9 25.4
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26.4
28.3 13.6 18.6 13.2 20.3 12.4 21.6 21.9 24.3 23.4 26.1 20.2 17.2 18.3 23.1 34.6
22.1 12.6 13.7 0 14.9 0 15.9 19.3 18.6 16.9 20.8 17.3 15.2 15.8 19.3 23.4
25.4 11.7 14.2 0 15.8 0 16.8 20.6 19.3 17.3 21.4 17.6 16.3 12.4 20.6 26.3
26.3 0 15.2 0 16.4 0 17.9 20.9 20.4 18.2 22.6 18.3 17.3 17.8 20.9 24.8
13.8 13.6 0 0 0 0 0 0 0 0 0 0 0 0 0 17.3
23.5 18.3 12.6 0 15.6
21.8 15.4 13.6 0 16.2
26.8 17.9 17.9 0 17.9
0 21.9 0 0 0
17.8 18.3 20.3 18.6 20.6 17.3 13.6 14.2 19.3 23.7
18.9 16.3 21.6 19.3 20.0 18.2 12.5 11.6 18.9 21.9
20.3 19.9 23.4 23.4 24.3 20.3 16.2 12.5 21.4 25.4
0 0 0 0 0 0 0 12.7 0 26.4
S.a., Staphylococcus aureus; S. e., Staphylococcus epidermidis’ S.p., Streptococcus pyogenes; B. s., Bacillis subtilis; P. v., Proteous vulgaris; K. p., Klebsiella pneumonia; S. f., Shigella flexneri; P. a., Pseudomonas aeruginosa; A.f., Aspergillus fumigates; A.c., Aspergillus clavatus; C. a., Candida albicans; G. c., Geotricum candidum
Table 2 Minimum inhibitory concentration (µg/ml) of the more potent synthesized compounds against the pathological organisms. Compd.
Gram − ve
Gram + ve
Fungi
No.
S. aureus
S. epidermidis
B. subtilis
P. vulgaris
K. pneumonia
S. flexneri
A. fumigatus
A clavatus
1 11 13 14 15 16 19 St.
0.007 1.95 1.95 1.95 0.03 0.49 0.06 0.06
0.06 1.95 0.24 0.49 0.12 1.95 0.49 0.48
0.007 0.98 0.12 0.24 0.03 3.9 0.24 0.007
0.49 31.25 7.81 31.25 3.9 31.25 3.9 1.95
0.06 31.25 3.9 15.63 0.98 15.63 1.95 0.24
0.03 7.81 1.95 7.81 0.49 7.81 0.98 0.48
0.24 15.63 1.95 7.81 0.98 15.63 3.9 0.97
0.98 7.81 0.98 3.9 1.95 7.81 7.8 1.95
growth of A. fumigates (MIC 0.24 µg/mL) and showed twofold potency of amphotricin B in inhibiting the growth of A. clavatus (MIC 0.98 µg/mL). Interestingly compound 1 was exhibited significant antitumor activity against G. candidum (MIC 0.03 µg/ mL) more than amphotricin B (MIC 0.48 µg/mL). Thiazolidinone 11 was moderately active against S. aureus, S. epidermidis and B. subtilis; while compound N-phenylthiazolidinone 12 has good activity MIC values (0.98–1.95 μg/mL). Concerning the antibacterial activity of 5-methyl thiazolidinone derivatives 13–15, the results displayed that compound N-phenyl-5-methylthiazolidinone 15 was the most active compound against the 3 bacterial strains with MIC values (0.03–0.12 μg/mL). 5-Methyl thiazolidinones 13–15 have good activity with MIC values (0.12–7.81 µg/ mL) against the 3 fungi. Moreover, the thiazolinones derivative 16 showed moderate activity against all screened bacterial strains, compound 19 was highly active with MIC values (0.06– 0.49 μg/mL). Among 4-methyl thiazolines 16, 19, compound 19 showed broad spectrum antifungal activity all the tested fungal microbes, while compound 16 exhibited moderate to good activity with MIC values (0.12–7.81 µg/mL) against the against the screened fungi except C. albicans.
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
G. candidum 0.03 1.95 0.24 0.98 0.12 1.95 0.98 0.48
Conflict of Interest
▼
The authors declare no conflicts of interest.
References
1 Abbas SY, El-Sharief MAMSh, Basyouni WM et al. Thiourea derivatives incorporating a hippuric acid moiety: Synthesis and evaluation of antibacterial and antifungal activities. Eur J Med Chem 2013; 64: 111–120 2 El-Sharief MAMSh, Abbas SY, El-Bayouki Kh AM et al. Synthesis of thiosemicarbazones derived from N-(4-hippuric acid) thiosemicarbazide and different carbonyl compounds as antimicrobial agents. Eur J Med Chem 2013; 67: 263–268 3 Helal MH, Abbas SY, Salem MA et al. Synthesis and characterization of new types of 2-(6-methoxy-2-naphthyl)propionamide derivatives as potential antibacterial and antifungal agents. Med Chem Res 2013; 22: 5598–5609 4 Aly MM, Mohamed YA, El-Bayouki Kh AM et al. Synthesis and biological activity of some 4(3H)-quinazolinone-2-carboxaldehyde thiosemicarbazone and their metal complexes. Eur J Med Chem 2010; 45: 3365–3373 5 Abbas SY, Farag AA, Ammar YA et al. Synthesis, characterization, and antiviral activity of novel fluorinated isatin derivatives. Monatsh Chem 2013; 144: 1725–1733 6 Sriram D, Yogeeswari P, Gopal G. Synthesis, anti-HIV and antitubercular activities of lamivudine prodrugs. Eur J Med Chem 2005; 40: 1373–1376
Downloaded by: University of Georgia Libraries. Copyrighted material.
Compd
Original Article 379 12 Raparti V, Chitre T, Bothara K et al. Novel 4-(morpholin-4-yl)N0-(arylidene) benzohydrazides: Synthesis, antimycobacterial activity and QSAR investigations. Eur J Med Chem 2009; 44: 3954–3960 13 Farrag AA, Ammar YA, El-Sehemi AG et al. Synthesis and anticancer activity of some fluorinated compounds containing quinoxaline moiety. Egyptian J biomed Sci 2010; 34: 13–25 14 Farag AA, Khalifa EM, Sadik NA et al. Synthesis, characterization and evaluation of some novel 4(3H)-quinazolinone derivatives as antiinflammatory and analgesic agents. Med Chem Res 2013; 22: 440–452 15 Ivachtchenko AV, Khvat AV, Kobak VV et al. A new insight into the Pfitzinger reaction. A facile synthesis of 6-sulfamoylquinoline-4-carboxylic acids. Tetrahedron Lett 2004; 45: 5473–5476
Downloaded by: University of Georgia Libraries. Copyrighted material.
7 Pandeya SN, Sriram D, Nath G et al. Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-4-(4′-chlorophenyl)thiazol-2-yl] thiosemicarbazide. Eur J Pharm Sci 1999; 9: 25–31 8 Bondock S, Naser T, Ammar YA. Synthesis of some new 2-(3-pyridyl)4,5-disubstituted thiazoles as potent antimicrobial agents. Eur J Med Chem 2013; 62: 270–279 9 Mehta DP, Sengar NPS, Pathak AK. 4-Thiazolidinone- a new profile of various pharmacological activities. Oriental J of Chem 2008; 24: 441–454 10 Farag AA, Abd-Alrahman SN, Ahmed GF et al. Synthesis of some azoles incorporating sulfonamide moiety as anticonvulsant agents. Arch Pharm 2012; 345: 703–712 11 El-Bayouki Kh AM, Basyouni WM, Mostafa EA et al. Synthesis, characterization and molluscicidal activity of Mn, Co, Ni and Cu metal complexes of ethyl 5-amino-2-(methylthio) thiazole-4-carboxylate. Synth React Inorg Met-Org 2014; 44: 537–540
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Author
A. A. Farag
Affiliation
Department of Chemistry, Faculty of Science (Girl’s), Al-Azhar University, Nasr City, Cairo, Egypt
Key words ▶ thiosemicarbazones ● ▶ thiosemicarbazide ● ▶ antibacterial and antifungal ● activities
Abstract
▼
This article describes the synthesis of novel 5-(morpholinosulfonyl)isatin derivatives having biologically active thiazole moiety were synthesized via 2 synthetic routes. The first route involved interaction of 5-(morpholino-sulfonyl) isatin with aminothiazole derivatives to give the Schiff’s base derivatives (2, 3). The second route involved preparation of thiosemicarbazones (4–7) by treatment of 5-(morpholino- sulfonyl)
Introduction
▼
received 13.03.2014 accepted 02.07.2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1384609 Published online: August 12, 2014 Drug Res 2015; 65: 373–379 © Georg Thieme Verlag KG Stuttgart · New York ISSN 2194-9379 Correspondence A. A. Farag Department of Chemistry Faculty of Science (Girl’s) Al-Azhar University PO box 11754 Yousef Abbas Str., Nasr City Cairo Egypt Tel.: + 20/233/335 929 Fax: + 20/233/370 931 [email protected]
Despite many significant progresses in antimicrobial therapy, infectious diseases caused by bacteria and fungi remain a major worldwide health problem due to rapid development of resistance to the existing antimicrobial drugs. So, the medical community faces a serious problem against infections caused by the pathogen microbes and needs an effective therapy and search for novel antimicrobial agents [1–4]. Various derivatives of isatin are known to possess a range of pharmacological properties. In recent years, isatin derivatives are reported to exhibit broad spectrum chemotherapeutic properties such as antiviral [5], anti-TB [6], antifungal, and antibacterial activities [7]. Investigation of the structure activity relationships in isatin derivatives revealed that 5-halogenation, and 3-thiosemicarbazone formation was effective in causing a marked rise in activity against various bacteria, fungi and virus [5–7]. In addition, cyclization of isatin-3-thisemicarbazones to 4-thiazoline, and 4-thiazolidinone, was efficient in increasing antimicrobial activity [5]. There has been a considerable interest in the chemistry of thiazole ring system, which is a core structure in various synthetic pharmaceuticals displaying a broad spectrum of biological activities [8–11].
isatin with thiosemicarbazides followed by cycloalkylation of the products with halogenated compounds to give the thiazole derivatives (8–19). Most of the synthesized compounds were screened against Gram (+), Gram (−) bacterial and fungi. The best gram positive activity was displayed by compounds 1, 13, 14, 15, 16 and 18 and the best gram negative bacteria was showed by compounds 1, 12, 13, 15, and 19, whereas compounds 1, 12, 13, 15, and 19 exhibited the best antifungal activity.
Literature survey reveals that morpholine ring is important for antimicrobial activity [12]. As a part of our extensive research program to rapidly assemble novel bioactive compounds under mild conditions [13, 14] and the aforementioned microbial inhibitory activities of isatin derivatives prompted us to attach sulfonylmorpholinyl isatin to the 4-thiazolidinone scaffold. The combination of 2 privileged structures in one molecule leads to drug-like molecules, also to study the effect of the substituent on the activities and make a comparative study to deduce a structure activity relationship.
Experimental Section
▼
All melting points were determined on an electrothermal Gallenkamp apparatus and are uncorrected. The IR spectra were measured on a Mattson 5 000 FT-IR Spectrometer in potassium bromide discs. The NMR spectra were recorded in DMSO-d6 on a Bruker WP spectrometer (500 MHz) and the chemical shifts δ downfield from TMS as an internal standard. The mass spectra were recorded on Finnegan MAT 212 instrument, the ionizing voltage was 70 ev. Elemental analyses were carried out by the Microanalytical unit of Faculty of Science, Cairo
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
Synthesis and Antimicrobial Activity of 5-(morpholino sulfonyl)isatin Derivatives Incorporating a Thiazole Moiety
374 Original Article
5-(Morpholin-4-ylsulfonyl)-1H-indole-2,3-dione (1)
5-(Morpholinosulfonyl)isatin (1) was synthesized according to reported paper [15], orange crystals; yield 86 %; mp 176–177 ℃; IR: ν/cm − 1: 3 315 (NH) and 1 757 (C = O); 1H NMR: δ/ppm = 2.88 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.63 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.13 (d, 1H, J = 8.2 Hz, indole-H), 7.69 (m, 1H, indole-H), 7.91 (m, 1H, indole-H ), 11.49 (s, 1H, NH, D2O-exchangeable); 13C NMR: 46.3 (2 × CH2), 65.8 (2 × CH2), 113.4, 118.6, 123.9, 129.7, 137.6, 154.5, 159.8(C = O), 183.4 (C = O); Anal. Calcd for C12H12N2O5S (296.30): C, 48.64; H, 4.08; N, 9.45; Found: C, 48.42; H, 4.11; N, 9.63.
Synthesis of Schiff’s bases 2,3
A mixture of isatin 1 (0.01 mol) and the requisite amine (namely, 2-aminothiazole, 3-amino-2-thioxothiazolidin-4-one) (0.01 mol) in acetic acid (50 mL) was heated under reflux for 2 h. The reaction mixture was concentrated and the residue was allowed to come to ambient temperature. The solid product was filtered and recrystallized from dioxane to give 2 and 3, respectively.
5-(Morpholinosulfonyl)-3-(thiazol-2-ylimino)indolin-2one (2)
Reddish brown crystals; yield 84 %; mp 234–235 ℃; IR: υ/ cm − 1 = 3 390 (NH) and 1 701 (C = O); 1H NMR: δ/ppm = 2.86 (t, 4H, J = 4.1 Hz, 2 × CH2), 3.83 (t, 4H, J = 4.0 Hz, 2 × CH2), 7.15–7.98 (m, 5H, Ar-H and thiazole H4, 5), 11.55 (s, 1H, NH, D2O-exchangeable); Anal. Calcd for C15H14N4O4S2 (378.43): C, 47.61; H, 3.73; N, 14.81; Found: C, 47.78; H, 3.52; N, 14.98.
3-(5-(Morpholinosulfonyl)-2-oxoindolin-3ylideneamino)-2-thioxothiazolidin-4-one (3)
Reddish brown crystals; yield 85 %; mp > 300 ℃; IR: υ/ cm − 1 = IR: ν/cm − 1: 3 317, 3 233 (NH) and 1 699 (C = O); 1HNMR: δ/ppm: 2.91 (d, 4H, J = 4.0 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.0 (s, 2H, CH2), 7.20 (d, 1H, J = 8.0 Hz, indole-H), 7.80 (d, 1H, J = 8.4 Hz, indole-H), 9.26 (s, 1H, indole-H), 11.78 (s, 1H, 1NH, D2Oexchangeable); MS, m/z ( %): 426 (M + ; 12.9), 277 (19.3), 174 (13.5), 86 (100); Anal. Calcd for C15H14N4O5S3 (426.49): C, 42.24; H, 3.31; N, 13.14; Found: C, 42.45; H, 3.21; N, 13.35.
Synthesis of thiosemicarbazone derivatives 4–7
The mixture of 5-(morpholinosulfonyl) isatin (1) (0.01 mol) and the desired thiosemicarbazide derivative (namely thiosemicarbazide, N-(methyl)thiosemicarbazide, N-(ethyl)thiosemicarbazide, N-(phenyl)thiosemicarbazide) (0.01 mol) in acetic acid (50 mL) was heated under reflux for 0.5 h. the reaction mixture was allowed to come to ambient temperature. The resultant solid product so precipitated was collected, and crystallized from dioxane to give the desired thiosemicarbazones 4–7.
2-(5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazinecarbothioamide (4)
Yellow crystals; yield 92 %; mp 222 ℃; IR: ν/cm − 1: 3 417, 3 232, 3 145 (NH, NH2) and 1 704 (C = O). 1HNMR: δ/ppm: 2.93 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.22 (d, 1H, J = 8.0 Hz, indole-H), 7.77 (d, 1H, J = 8.4 Hz, indole-H), 8.16 (s, 1H, indole-H), 9.21 (s, 2H, NH2, D2O-exchangeable); 11.65, 12.33 (2 s, 2H, 2NH, D2O-exchangeable); 13C NMR: 46.4 (2 × CH2), 65.7 (2 × CH2), 111.8, 120.9, 121.4, 128.5, 130.9, 131.2, 146.4 (C = N), 163.2 (C = O), 179.3 (C = S); MS, m/z ( %): 369 (M + ; 93.5), 368 Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
(73.0), 243 (12.5), 229 (89.1), 155 (94.7), 145 (24.0), 140 Anal. Calcd for C13H15N5O4S2 (369.42): C, 42.27; H, 4.09; N, 18.96; Found: C, 42.33; H, 4.12; N, 18.88.
N-Methyl-2-(5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazinecarbothio-amide (5)
Yellow crystals; yield 87 %; mp 271–273 ℃; IR: ν/cm − 1: 3 400, 3 249 (NH) and 1 711 (C = O); 1HNMR: δ/ppm: 2.92 (t, 4H, J = 4.2 Hz, 2 × CH2), 3.02 (d, 3H, J = 4.5 Hz, NHCH3), 3.73 (t, 4H, J = 4.1 Hz, 2 × CH2), 7.00 (br, 1H, NHCH3, D2O-exchangable), 7.24 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.17 (s, 1H, indole-H); 11.65, 11.8 (2 s, 2H, 2NH, D2O-exchangeable); 13 C NMR: 31.8 (CH3), 46.3 (2 × CH2), 65.8 (2 × CH2), 111.8, 120.5, 121.4, 129.4, 130.5, 131.0, 146.2 (C = N), 163.1 (C = O), 178.4 (C = S); Anal. Calcd for C14H17N5O4S2 (383.45): C, 43.85; H, 4.47; N, 18.26; Found: C, 43.77; H, 4.52; N, 18.54.
N-Ethyl-2-(5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazinecarbothio-amide (6)
Yellow crystals; yield 92 %; mp 243–245 ℃; IR: υ/cm − 1 = 3 382, 3 288 (NH), 1 709 (C = O); 1H NMR: δ/ppm = 1.21 (t, 3H, J = 6.85 Hz, CH3), 2.88 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.65 (m, 6H, 3 × CH2), 7.16 (d, 1H, J = 8.0 Hz, indole-H), 7.72 (d, 1H, J = 8.4 Hz, indole-H), 8.05 (s, 1H, indole-H), 9.55, 11.20, 12.26 9.55(t,1H, 1NH, D2O-exchangable) and 11.20, 12.26 (2 s, 2H, 2NH, D2O-exchangable); 13C NMR: 14.4 (CH3), 39.3 (CH2), 46.4 (2 × CH2), 65.7 (2 × CH2), 111.9, 120.6, 121.8, 128.2, 130.7, 131.2, 147.0 (C = N), 163.2 (C = O), 178.4 (C = S); MS, m/z ( %): 397 (M + ; 15.3), 369 (33.5), 296 (19.5), 131 (17.1), 103 (45.5), 89 (100); Anal. Calcd for C15H19N5O4S2 (397.47): C, 45.33; H, 4.82; N, 17.62; Found: C, 45.21; H, 4.72; N, 17.82.
2-(5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene)-Nphenylhydrazinecarbothioamide (7)
Yellow crystals; yield 79 %; mp 254–255 ℃; 3 387, 3 276 (NH) and 1 706 (C = O); 1HNMR: δ/ppm: 2.92 (t, 4H, J = 4.1 Hz, 2CH2), 3.73 (t, 4H, J = 4.2 Hz, 2CH2), 6.93–7.65 (m, 6H, Ar-H), 7.75 (d, 1H, J = 8.4 Hz, indole-H), 8.19 (s, 1H, indole-H), 10.81, 11.22, 12.67 (3 s, 3H, 3NH, D2O-exchangeable); 13C NMR: 46.4 (2 × CH2), 65.9 (2 × CH2), 111.9, 121.1, 121.3, 126.4 (2H), 126.7, 128.8 (2H), 129.5, 131.1, 131.4, 138.9, 146.5 (C = N), 163.2 (C = O), 177.3 (C = S); Anal. Calcd for C19H19N5O4S2 (445.52): C, 51.22; H, 4.30; N, 15.72; Found: C, 51.41; H, 4.43; N, 15.88.
Synthesis of Thiazole Derivatives
▼
A mixture of the thiosemicarbazide derivatives 4–7 (0.01 mol), ethyl chloroacetate, ethyl 2-chloropropanoate or chloroacetone (0.01 mol) and fused sodium acetate (0.02 mol) in acetic acid (50 mL) was heated under reflux for 6 h. The reaction mixture was allowed to come to ambient temperature. The obtained product was collected by filtration and recrystallized from the appropriate solvent to give 8–11, 12–15 and 16–19, respectively.
2-((5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazono)thiazolidin-4-one (8)
Reddish brown crystals; yield 79 %; mp 254–255 ℃; IR: ν/cm − 1: 3 399, 3 287 (NH) and 1 698 (C = O); 1H NMR: δ/ppm = 2.82 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.69 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.13 (s, 2H, CH2), 7.17 (d, 1H, J = 8.0, indole-H), 7.75 (d, 1H, J = 8.4, indole-H), 8.54 (s, 1H, indole-H), 11.53, 12.13 (2 s, 2H, 2NH, D2O-exchangeable);
Downloaded by: University of Georgia Libraries. Copyrighted material.
University. Antimicrobial screening was carried out in Regional Center for fungi and its applications in Al-Azher University.
Original Article 375
3-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin3ylidene)hydrazono)thiazolidin-4-one (9)
Reddish crystals; yield 79 %; mp 258–260 ℃; IR: ν/cm − 1: 3 303 (NH), 1 707(C = O); 1H NMR: δ/ppm = 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.19 (3H, s, CH3), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.11 (s, 2H, CH2), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.41(s, 1H, NH, D2O-exchangeable); 13C NMR: 30.0 (CH3), 33.1 (CH2), 46.4 (2 × CH2), 65.9 (2 × CH2), 111.4, 117.6, 128.0, 128.7, 132.9, 147.9, 148.4, 165.2 (C = N), 172.8 (C = O), 174.4 (C = O); Anal. Calcd for C16H17N5O5S2 (423.47): C, 45.38; H, 4.05; N, 16.54; Found: C, 45.46; H, 4.26; N, 16.74.
3-Ethyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)thiazolidin-4-one (10)
117.6, 128.0, 128.7, 132.9, 147.9, 148.4, 158.6 (C = N), 172.8 (C = O), 176.3 (C = O); MS, m/z ( %): 437 (M + ; 5.9), 308 (31.4), 260 (28.5), 219 (21.3), 159 (16), 92 (100); Anal. Calcd for C17H19N5O5S2 (437.49): C, 46.67; H, 4.38; N, 16.01; Found: C, 46.78; H, 4.23; N, 16.26.
3-Ethyl-5-methyl-2-((5-(morpholinosulfonyl)-2oxoindolin-3-ylidene)hydrazono) thiazolidin-4-one (14)
Reddish brown crystals; yield 92 %; mp 241–242 ℃; IR: ν/cm − 1: 3 327 (NH) and 1 707 (C = O); 1H NMR: δ/ppm = 1H NMR: δ/ ppm = 1.55 (d, 3H, CH3), 3.06 (s, 3H, NCH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 3.88 (q, 2H, CH2), 4.38 (q, 1H, CH), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.62 (s, 1H, NH, D2Oexchangeable); Anal. Calcd for C18H21N5O5S2 (451.52): C, 47.88; H, 4.69; N, 15.51; Found: C, 47.93; H, 4.51; N, 15.67.
5-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)-3-phenyl- thiazolidin-4-one (15)
Reddish brown crystals; yield 79 %; mp 250–252 ℃; IR: υ/ cm − 1 = 3 447(NH), 1 732 (C = O); 1H NMR: δ/ppm = 1.28 (t, 3H, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 3.88 (q, 2H, CH2), 4.11 (s, 2H, CH2), 7.15 (d, 1H, J = 8.0 Hz, indoleH), 7.73 (d, 1H, J = 8.4 Hz, indole-H), 8.51 (s, 1H, indole-H), 11.62 (s, 1H, NH, D2O-exchangeable); 13C NMR: 12.5 (CH3), 33.3 (CH2), 38.90 (CH2), 46.3 (2 × CH2), 65.7 (2 × CH2), 111.5, 117.5, 127.8 (3C), 133.1, 147.7 (C = N), 148.5 (C = N), 165.2 (C = O), 174.3 (C = O); Anal. Calcd for C17H19N5O5S2 (437.49): C, 46.67; H, 4.38; N, 16.01; Found: C, 46.46; H, 4.22; N, 16.17.
Brown powder; yield 92 %; mp 247–246 ℃; IR: υ/cm − 1 = 3 296 (NH), 1 756, 1 699 (C = O); 1H NMR: δ/ppm = 1.66 (d, 3H, CH3), 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 4.48 (q, 1H, CH), 7.00–8.05 (m, 8H, Ar-H), 11.26 (br, 1H, NH, D2Oexchangeable); 13C NMR: 19.8 (CH3), 42.1 (CH), 46.4 (2 × CH2), 67.02 (2 × CH2), 111.9, 121.1, 121.3, 126.4 (2H), 126.7, 128.8 (2H), 129.5, 131.1, 131.4, 138.9, 146.5 (C = N), 163.2 (C = O); Anal. Calcd for C22H21N5O5S2 (499.56): C, 52.89; H, 4.24; N, 14.02; Found: C, 53.08; H, 4.11; N, 14.30.
2-((5-(Morpholinosulfonyl)-2-oxoindolin-3-ylidene) hydrazono)-3-phenylthiazo- lidin 4-one (11)
3-((4-Methylthiazol-2(3H)-ylidene)hydrazono)-5(morpholinosulfonyl)indolin-2-one (16)
Brownish crystals; yield 79 %; mp 254–255 ℃; IR: υ/cm − 1 = 3 310 (NH), 1 709 (C = O); 1H NMR: δ/ppm = 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.71 (t, 4H, J = 4.1 Hz, 2 × CH2), 4.46 (s, 2H, CH2), 7.00– 8.05 (m, 8H, Ar-H), 11.26 (br, 1H, NH, D2O-exchangeable); Anal. Calcd for C21H19N5O5S2 (485.45): C, 51.95; H, 3.94; N, 14.42; Found: C, 52.18; H, 4.08; N, 14.66.
5-Methyl-2-((5-(morpholinosulfonyl)-2-oxoindolin-3ylidene)hydrazono)thiazolid- in-4-one (12)
Reddish brown crystals; yield 92 %; mp 243–245 ℃; IR: ν/cm − 1: 3 398, 3 287 (2NH) and 1 698 (C = O); 1H NMR: δ/ppm = 1.52 (d, 3H, J = 9 Hz, CH3), 2.82 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.69 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.33 (q, 1H, J = 9 Hz, CH), 7.17 (d, 1H, J = 8.0, indole-H), 7.75 (d, 1H, J = 8.4 Hz, indole-H), 8.54 (s, 1H, indole-H), 11.92, 12.13 (2 s, 2H, 2NH, D2O-exchangeable); 13C NMR: 19.78 (CH3), 45.13 (CH), 158.61 (N = C), 176.30 (NC = O). 12.5 (CH3), 33.3 (CH2), 38.90 (CH2), 46.3 (2 × CH2), 65.7 (2 × CH2), 111.5, 117.5, 127.8 (3C), 133.1, 147.7 (C = N), 148.5 (C = N), 165.2 (C = O), 174.3 (C = O); MS, m/z ( %): 423 (M + ; 1.7), 367 (4.0), 57 (100), Anal. Calcd for C16H17N5O5S2 (423.47): C, 45.38; H, 4.05; N, 16.54; Found: C, 45.45; H, 4.01; N, 16.67.
3,5-Dimethyl-2-((5-(morpholinosulfonyl)-2-oxoindolin3-ylidene)hydrazono)-thiazo lidin-4-one (13)
Reddish brown crystals; yield 92 %; mp 240–242 ℃; IR: ν/cm − 1: 3 355 (NH) and 1 704 (C = O); 1H NMR: δ/ppm = 1.55 (d, 3H, J = 9 Hz, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.06 (s, 3H, NCH3), 3.64 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.38 (q, 1H, J = 9 Hz, CH), 7.15 (d, 1H, J = 8.0 Hz, indole-H), 7.73 (d, 1H, J = 8.4, indole-H), 8.51 (s, 1H, indole-H), 11.41(s, 1H, NH, D2O-exchangeable); 13C NMR: 19.7 (CH3), 31.2 (CH3), 45.1 (CH), 46.4 (2 × CH2), 65.9 (2 × CH2), 111.4,
Brown crystals, yield 79 %; mp 254–255 ℃; IR: υ/cm − 1 = 3 390 (NH) and 1 701(C = O); 1H NMR: δ/ppm = 2.33 (s, 3H, CH3), 2.85 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.61 (s, 1H, thiazole), 7.09 (d, 1H, J = 8.0, indole-H), 7.61 (d, 1H, J = 8.4 Hz, indole-H), 8.58 (s, 1H, indole-H), 11.02, 11.8 (2 s, 2H, 2NH, D2Oexchangeable); 13C NMR: 14.3 (CH3), 46.4 (2 × CH2), 65.9 (2 × CH2), 102.6, 110.1, 111.8, 118.7, 125.2, 127.9, 130.3, 136.8, 145.7 (C = N), 166.2 (C = O, 179.4 (C = O); Anal. Calcd for C16H17N5O4S2 (407.47): C, 47.16; H, 4.21; N, 17.19; Found: C, 47.44; H, 4.01; N, 17.34.
3-((3,4-Dimethylthiazol-2(3H)-ylidene)hydrazono)-5(morpholinosulfonyl)indolin-2-one (17)
Reddish crystals; yield 73 %; m.p. 297–298 ℃; IR: ν/cm − 1: 3 334 (NH), 1 700 (C = O); 1H NMR: δ/ppm = 1.79 (s, 3H, CH3), 2.74 (s, 3H, CH3), 2.86 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.67 (t, 4H, J = 3.9 Hz, 2 × CH2), 6.63 (s, 1H, thiazole), 7.11 (d, 1H, J = 8.0 Hz, indole-H), 7.64 (d, 1H, J = 8.4 Hz, indole-H), 8.59 (s, 1H, indole-H), 11.13 (s, 1H, NH, D2O-exchangeable); 13C NMR: 21.4 (CH3), 32.7 (CH3), 46.4 (2 × CH2), 65.8 (2 × CH2), 101.9, 110.2, 118.6, 125.7, 127.9, 130.0, 138.4, 145.9, 166.1, 172.1, 176.9; Anal. Calcd for C17H19N5O4S2 (421.49): C, 48.44; H, 4.54; N, 16.62; Found: C, 48.56; H, 4.36; N, 16.51.
3-((3-Ethyl-4-methylthiazol-2(3H)-ylidene)hydrazono)5-(morpholinosulfonyl)indolin-2-one (18)
Reddish brown powder; yield 65 %; m.p. 276–277 ℃; IR: ν/cm − 1: 3 430 (NH) and 1 700(C = O); 1H NMR: δ/ppm = 1.37 (t, 3H, CH3), 2.33 (s, 3H, CH3), 2.85 (t, 4H, J = 4.3 Hz, 2 × CH2), 3.65 (t, 4H, J = 3.9 Hz, 2 × CH2), 4.14 (q, 2H, CH2), 6.61 (s, 1H, thiazole), 7.09 (d, 1H, J = 8.0 Hz, indole-H), 7.61(d, 1H, J = 8.4 Hz, indole-H), 8.58 Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
Anal. Calcd for C15H15N5O5S2 (409.44): C, 44.00; H, 3.69; N, 17.10; Found: C, 44.12; H, 3.84; N, 17.23.
(s, 1H, indole-H), 11.02 (s, 1H, NH, D2O-exchangeable); 13C NMR: 13.3 (CH3), 13.7 (CH3), 40.6 (CH2), 46.4 (2 × CH2), 65.7 (2 × CH2), 102.6, 110.3, 118.6, 125.5, 127.0, 130.3, 137.8, 138.2, 145.9, 166.1, 176.3; MS, m/z ( %): 435 (M + ; 80.9), 322 (23.1), 230 (20.3), 173 (19.8) 139 (61.6), 128 (60.1), 114 (100); Anal. Calcd for C18H21N5O4S2 (435.52): C, 49.64; H, 4.86; N, 16.08; Found: C, 49.84; H, 4.77; N, 16.23.
functions, and at 1 704 cm − 1 due to C = O function. The “1H NMR” spectrum revealed 2 broad singlet signals at δ = 9.21 ppm assignable to NH2 protons, 2 singlet signals at δ = 11.65, 12.33 ppm characteristic to 2NH protons. 13C NMR showed signals at 46.4 corresponding to N(CH2)2 and at 64.7 attributed to O(CH2)2. The mass spectrum showed a molecular ion peak (M + ) at m/z = 369 (93.5) corresponding to a molecular formula C13H15N5O4S2. We have extended our synthetic program to utilize structure 4–7 as the key starting materials for cycloalkylation on the hope of obtaining thiazole derivatives with better biological activity. When thiosemicarbazones 4–7 were reacted with ethyl chloroacetate, the corresponding thiazolidine derivatives 8–11 were obtained. Elemental analyses and spectral data were in favor of these proposed thiazole structure. The IR spectrum of 10 showed absorption bands at 3 447 and 1 732 cm − 1 due to NH and C = O groups, respectively. The “1H NMR” spectrum showed a triplet signal in the region at 4.11 ppm corresponding to the CH3 protons together with a quartet and singlet signals at 3.88, 4.11 ppm corresponding to CH2 ethyl and CH2 thiazole protons. Similarly, the novel thiazolidinone 12–15 could be achieved via the reaction of 4–7 with ethyl 2-chloropropanoate. The structure of the prepared compounds was elucidated on the basis of elemental analyses and spectral data. In addition, treatment 4–7 with chloroacetone furnished the corresponding thiazole derivatives 16– 19. The thiazoles 16–19 were assigned for the reaction product on the basis of their elemental analyses and spectral data. The IR spectrum of 19 revealed absorption bands at 3 380 and 1 729 cm − 1 characteristic NH and C = O functions, respectively. The “1H NMR” spectrum of 19 exhibited signals at 1.94, 2.93, 3.59 and 6.73 ppm assignable to CH3, 2 morpholinyl 2CH2 and thiazole H-5 protons, respectively. Moreover, its 13CNMR spectrum revealed 23 carbons, the most important signals are 14.8, 46.1, 65.6, 165.9 and 178.5 which are characteristics for CH3, N(CH2)2, O(CH2)2, C = N, carbonyl carbons, respectively.
3-((4-Methyl-3-phenylthiazol-2(3H)-ylidene) hydrazono)-5-(morpholinosulfonyl)- indolin-2-one (19)
Brownish crystals; yield 72 %; m.p. 265–267 ℃; IR: υ/cm − 1 = 3 380 (NH), 1 729 (C = O); 1H NMR: δ/ppm = 1.94 (s, 3H, CH3), 2.93 (t, 4H, J = 4.4 Hz, 2 × CH2), 3.59 (t, 4H, J = 4.3 Hz, 2 × CH2), 6.73 (s, 1H, CH-thiazole), 7.00 (d, 1H, J = 8.0 Hz, indole-H), 7.45–7.60 (m, 6H, Ar-H), 7.74 (s, 1H, indole-H), 10.59 (s, 1H, NH, D2O-exchangeable); 13C NMR: 14.8 (CH3), 46.1 (2CH2), 65.6 (2CH2), 103.0, 110.1, 118.0, 125.3, 126.9, 128.2 (2C), 129.8, 130.3 (2C), 130.9, 136.6, 137.7, 138.8, 146.0, 165.9, 178.5; Anal. Calcd for C22H21N5O4S2 (483.56): C, 54.64; H, 4.38; N, 14.48; Found: C, 54.78; H, 4.18; N, 14.67.
Results and Discussion
▼
The synthetic strategies adopted for the synthesis of the intermediates and target compounds are depicted in ● ▶ Fig. 1, 2. The reactivity of 5-(morpholinosulfonyl)isatin (1) [13] towards some different aminothiazole derivatives was studied with the objective of obtaining biologically active compounds. Thus, reaction of 1 with 2-aminothiazole or 3-amino-2-thioxothiazolidin4-one afforded the corresponding thiazoleimino derivatives 2 and 3. The structures of 2 and 3 have been assigned as a reaction product on the basis of analytical and spectral data. The IR spectrum of 3 displayed absorption bands at 3 317, 3 233 (NH) cm − 1 due to NH function and at 1 699 cm − 1 corresponding to C = O function. The “1H NMR” spectrum exhibited a singlet signal at δ = 6.0 ppm assignable to thiazolidine-CH2 protons, another 2 triplet signals at δ = 2.91 and 3.65 ppm specific for morpholinyl protons and a singlet signal at δ = 11.78 ppm due to NH proton. The behaviour of the 1 towards some thiosemicarbazides to obtain polyfunctionally substituted thiazole moiety of potential pharmaceutical interest, has been investigated. 5-morpholinosulfonyl isatin was reacted with thiosemicarbazide derivatives in acetic acid under reflux condition, a product that was identified as 5-morpholinosulfonylisatin-3-thiosemicar- bazones 4–7. The structure was assigned on the basis of the elemental analyses and spectral data. The IR spectrum of 4 showed absorption bands at 3 417, 3 232, 3 145 cm − 1 corresponding to NH and NH2 N H2N
O
S
N
S
Antibacterial and Antifungal Activities
▼
Most of the newly synthesized target compounds were evaluated for their in vitro antimicrobial activities against the human pathogens Staphylococcus aureus (RCMB 010027), Staphylococcus epidermidis (RCMB 010024), Streptococcus pyogenes (RCMB 010015) and Bacillis subtilis (RCMB 010063) as examples of Gram-positive bacteria and Proteous vulgaris (RCMB 010085), Klebsiella pneumonia (RCMB 010093), Shigella flexneri (RCMB 0100542) and Pseudomonas aeruginosa (RCMB 010043) as examples of Gram-negative bacteria. They were also evaluated for their potential antifungal activities against the following
N S
O
2 O N
S
O
Fig. 1 Synthesis of Schiff’s bases derivatives.
N
O
N H
O
O S
O
1
N H
O
H2N
N
S
S O
O
N
S
O
N
O
3
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
N H
O
N O
S
Downloaded by: University of Georgia Libraries. Copyrighted material.
376 Original Article
Original Article 377
O O S N
O
1
N H
O
O O S N
ClCH2COOEt
RNHCSNHNH2 O N
S
O
N H 8-11
S
O
N
O 4-7
N H
N H
NHR
O Cl
O
OC2H5
O
CH3
N O
O
ClCH2COCH3
N
S
O
O
N N N H 16-19
O
R N
N N
CH3
S
O
R N
O
S
O
N N N O H 12-15
R N S
O CH3
S 4,8,12,16 R = H 5,9,13,17 R = CH3 6,10,14,18 R = C2H5 7,11,15,19 R = C6H5
Fig. 2 Synthesis of thiosemicarbazone and thiazole derivatives.
fungal strains; Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593), Candida albicans (RCMB 05035) and Geotricum candidum (RCMB 05096). Agar-diffusion method was used for the determination of the preliminary screening of antibacterial and antifungal activities. Ampicillin and amphotricin B were used as reference drugs. The results were recorded for each tested compound as the average diameter of inhibition zones of ▶ Table 1). bacterial or fungal growth around the discs in mm ( ● Certain aspects of the structure activity relationships for these compounds can be more clearly highlighted. The substitution at 3-position was referred by X. Compound No. 1, the X = O resulted in the highest antimicrobial activity among all the compounds investigated in this study. 5-(morpholinosulfonyl)isatin exhibited the highest antibacterial activity against most of the organisms and showed results greater than the reference drug. Compound 3, the × group have 2-thioxo-thiazolidin-4-one moiety; introduction of 2-thioxo-thiazolidin-4-one moiety had a detrimental effect on antibacterial activity, 3 showed moderate activities against the tested bacteria. Compounds 4, 6 the × group N-substituted thiosemicarbazone side chain moiety (4; H, 6 C2H5): Regarding the effect of N-substituted, it is evident that: It was noticed that the presence ethyl group (6) displayed detrimental effect on the antimicrobial activity. Compounds 9–11, the × group have hydrazono side chain ending with N-substituted thiazolidine moiety (9; CH3, 10; C2H5, 11; Ph): Regarding the effect of N-substituted, it is evident that: It was noticed that the presence ethyl group (10) at the thiazole ring displayed detrimental effect on the antimicrobial activity. The presence of phenyl moiety (11) resulted in the highest antimicrobial activity among this series. Compounds 12–15, the × group have hydrazono side chain ending with N-substituted thiazolidine moiety (12; H, 13; CH3, 14; C2H5, 15; Ph): Regarding the effect of N-substituted, it is evident that: the type of the substitutions on the thiazole moiety nearly does not have effect on antimicrobial
activity. The presence of phenyl moiety (15) resulted in the highest antimicrobial activity among this series. Compounds 16–19, the × group have hydrazono side chain ending with N-substituted thiazole moiety (16; H, 17; CH3, 18; C2H5, 19; Ph): Regarding the effect of N-substituted, it is evident that varying such a unit may have a dramatic effect on antimicrobial activity, which may be augmented or reduced depending on whether a matching or mismatching relationship exists with the N-substituted. The type of the substitutions on the thiazole moiety is important. It was noticed that the presence alkyl groups such as methyl and ethyl at the thiazole ring displayed detrimental effect on the antimicrobial activity. The presence of phenyl moiety (19) resulted in the highest antimicrobial activity among all the compounds investigated in this series. N- phenyl moiety exhibited activities near to the references drug.
MIC of the most Active Compounds
▼
The minimal inhibitory concentrations (MICs) for compounds that showed significant growth inhibition zones were determined. The synthesized compounds 1, 11, 13–16, 19 and reference drugs was then evaluated in vitro using the twofold serial dilution technique. The lowest concentration showing no growth was taken as the minimum inhibitory concentration (MIC). The results of minimum inhibitory concentration were reported in ● ▶ Table 2. Among this series, 5-(morpholinosulfonyl)isatin (1) showed highly inhibitory activity against all the screened bacteria when compared with ampicillin as revealed from their MIC values (0.007–0.49 μg/mL) and most of cases compound 1 was exhibited significant antibacterial activity more than Ampicillin. Regarding the activity of 1 against fungal strains, Compound 1 showed fourfold potency of amphotricin B in inhibiting the Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
Downloaded by: University of Georgia Libraries. Copyrighted material.
O
378 Original Article
Table 1 Antibacterial activity of the synthesized compounds against the pathological organisms expressed as inhibition diameter zones in millimeters (mm) based on well diffusion assay. Gram − ve
Gram + ve
Fungi
No.
S. a.
S. e.
S. p.
B. s.
P. v.
K. p.
S. f.
P. a.
A. f.
A c.
G. c.
C. a.
1 3 4 6 9 10 11 12 13 14 15 16 17 18 19 Stand.
29.3 12.6 14.6 11.3 16.9 10.6 19.6 20.9 20.6 20.6 26.3 22.3 15.3 17.6 25.3 28.9
25.3 11.7 16.2 12.4 19.3 9.3 20.3 19.3 23.4 22.4 24.2 20.6 14.6 14.2 22.9 25.4
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26.4
28.3 13.6 18.6 13.2 20.3 12.4 21.6 21.9 24.3 23.4 26.1 20.2 17.2 18.3 23.1 34.6
22.1 12.6 13.7 0 14.9 0 15.9 19.3 18.6 16.9 20.8 17.3 15.2 15.8 19.3 23.4
25.4 11.7 14.2 0 15.8 0 16.8 20.6 19.3 17.3 21.4 17.6 16.3 12.4 20.6 26.3
26.3 0 15.2 0 16.4 0 17.9 20.9 20.4 18.2 22.6 18.3 17.3 17.8 20.9 24.8
13.8 13.6 0 0 0 0 0 0 0 0 0 0 0 0 0 17.3
23.5 18.3 12.6 0 15.6
21.8 15.4 13.6 0 16.2
26.8 17.9 17.9 0 17.9
0 21.9 0 0 0
17.8 18.3 20.3 18.6 20.6 17.3 13.6 14.2 19.3 23.7
18.9 16.3 21.6 19.3 20.0 18.2 12.5 11.6 18.9 21.9
20.3 19.9 23.4 23.4 24.3 20.3 16.2 12.5 21.4 25.4
0 0 0 0 0 0 0 12.7 0 26.4
S.a., Staphylococcus aureus; S. e., Staphylococcus epidermidis’ S.p., Streptococcus pyogenes; B. s., Bacillis subtilis; P. v., Proteous vulgaris; K. p., Klebsiella pneumonia; S. f., Shigella flexneri; P. a., Pseudomonas aeruginosa; A.f., Aspergillus fumigates; A.c., Aspergillus clavatus; C. a., Candida albicans; G. c., Geotricum candidum
Table 2 Minimum inhibitory concentration (µg/ml) of the more potent synthesized compounds against the pathological organisms. Compd.
Gram − ve
Gram + ve
Fungi
No.
S. aureus
S. epidermidis
B. subtilis
P. vulgaris
K. pneumonia
S. flexneri
A. fumigatus
A clavatus
1 11 13 14 15 16 19 St.
0.007 1.95 1.95 1.95 0.03 0.49 0.06 0.06
0.06 1.95 0.24 0.49 0.12 1.95 0.49 0.48
0.007 0.98 0.12 0.24 0.03 3.9 0.24 0.007
0.49 31.25 7.81 31.25 3.9 31.25 3.9 1.95
0.06 31.25 3.9 15.63 0.98 15.63 1.95 0.24
0.03 7.81 1.95 7.81 0.49 7.81 0.98 0.48
0.24 15.63 1.95 7.81 0.98 15.63 3.9 0.97
0.98 7.81 0.98 3.9 1.95 7.81 7.8 1.95
growth of A. fumigates (MIC 0.24 µg/mL) and showed twofold potency of amphotricin B in inhibiting the growth of A. clavatus (MIC 0.98 µg/mL). Interestingly compound 1 was exhibited significant antitumor activity against G. candidum (MIC 0.03 µg/ mL) more than amphotricin B (MIC 0.48 µg/mL). Thiazolidinone 11 was moderately active against S. aureus, S. epidermidis and B. subtilis; while compound N-phenylthiazolidinone 12 has good activity MIC values (0.98–1.95 μg/mL). Concerning the antibacterial activity of 5-methyl thiazolidinone derivatives 13–15, the results displayed that compound N-phenyl-5-methylthiazolidinone 15 was the most active compound against the 3 bacterial strains with MIC values (0.03–0.12 μg/mL). 5-Methyl thiazolidinones 13–15 have good activity with MIC values (0.12–7.81 µg/ mL) against the 3 fungi. Moreover, the thiazolinones derivative 16 showed moderate activity against all screened bacterial strains, compound 19 was highly active with MIC values (0.06– 0.49 μg/mL). Among 4-methyl thiazolines 16, 19, compound 19 showed broad spectrum antifungal activity all the tested fungal microbes, while compound 16 exhibited moderate to good activity with MIC values (0.12–7.81 µg/mL) against the against the screened fungi except C. albicans.
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
G. candidum 0.03 1.95 0.24 0.98 0.12 1.95 0.98 0.48
Conflict of Interest
▼
The authors declare no conflicts of interest.
References
1 Abbas SY, El-Sharief MAMSh, Basyouni WM et al. Thiourea derivatives incorporating a hippuric acid moiety: Synthesis and evaluation of antibacterial and antifungal activities. Eur J Med Chem 2013; 64: 111–120 2 El-Sharief MAMSh, Abbas SY, El-Bayouki Kh AM et al. Synthesis of thiosemicarbazones derived from N-(4-hippuric acid) thiosemicarbazide and different carbonyl compounds as antimicrobial agents. Eur J Med Chem 2013; 67: 263–268 3 Helal MH, Abbas SY, Salem MA et al. Synthesis and characterization of new types of 2-(6-methoxy-2-naphthyl)propionamide derivatives as potential antibacterial and antifungal agents. Med Chem Res 2013; 22: 5598–5609 4 Aly MM, Mohamed YA, El-Bayouki Kh AM et al. Synthesis and biological activity of some 4(3H)-quinazolinone-2-carboxaldehyde thiosemicarbazone and their metal complexes. Eur J Med Chem 2010; 45: 3365–3373 5 Abbas SY, Farag AA, Ammar YA et al. Synthesis, characterization, and antiviral activity of novel fluorinated isatin derivatives. Monatsh Chem 2013; 144: 1725–1733 6 Sriram D, Yogeeswari P, Gopal G. Synthesis, anti-HIV and antitubercular activities of lamivudine prodrugs. Eur J Med Chem 2005; 40: 1373–1376
Downloaded by: University of Georgia Libraries. Copyrighted material.
Compd
Original Article 379 12 Raparti V, Chitre T, Bothara K et al. Novel 4-(morpholin-4-yl)N0-(arylidene) benzohydrazides: Synthesis, antimycobacterial activity and QSAR investigations. Eur J Med Chem 2009; 44: 3954–3960 13 Farrag AA, Ammar YA, El-Sehemi AG et al. Synthesis and anticancer activity of some fluorinated compounds containing quinoxaline moiety. Egyptian J biomed Sci 2010; 34: 13–25 14 Farag AA, Khalifa EM, Sadik NA et al. Synthesis, characterization and evaluation of some novel 4(3H)-quinazolinone derivatives as antiinflammatory and analgesic agents. Med Chem Res 2013; 22: 440–452 15 Ivachtchenko AV, Khvat AV, Kobak VV et al. A new insight into the Pfitzinger reaction. A facile synthesis of 6-sulfamoylquinoline-4-carboxylic acids. Tetrahedron Lett 2004; 45: 5473–5476
Downloaded by: University of Georgia Libraries. Copyrighted material.
7 Pandeya SN, Sriram D, Nath G et al. Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-4-(4′-chlorophenyl)thiazol-2-yl] thiosemicarbazide. Eur J Pharm Sci 1999; 9: 25–31 8 Bondock S, Naser T, Ammar YA. Synthesis of some new 2-(3-pyridyl)4,5-disubstituted thiazoles as potent antimicrobial agents. Eur J Med Chem 2013; 62: 270–279 9 Mehta DP, Sengar NPS, Pathak AK. 4-Thiazolidinone- a new profile of various pharmacological activities. Oriental J of Chem 2008; 24: 441–454 10 Farag AA, Abd-Alrahman SN, Ahmed GF et al. Synthesis of some azoles incorporating sulfonamide moiety as anticonvulsant agents. Arch Pharm 2012; 345: 703–712 11 El-Bayouki Kh AM, Basyouni WM, Mostafa EA et al. Synthesis, characterization and molluscicidal activity of Mn, Co, Ni and Cu metal complexes of ethyl 5-amino-2-(methylthio) thiazole-4-carboxylate. Synth React Inorg Met-Org 2014; 44: 537–540
Farag AA. Isatins as Antimicrobial Agents … Drug Res 2015; 65: 373–379
