Planta Med. 57(1991) 457
Two New 8-Oxotetrahydroprotoberberine Alkaloids, Gusanlung A and B, from Acangelisia gusanlung and Zhong-Liang Chen1 Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 319 Yue-Yang Road, Shanghai 200031, People's Republic of China 2 Address for correspondence fin-S heng Zhang
1.2
1
Received: June 27, 1990
Two new 8 -oxotetrahydroprotoberberine alkaloids, gusanlung A (1) and B (2), together with known
isoquinoline alkaloids, berberine and jatrorrhizine,
The plants of A. gusanlung were collected in the Hainan Province of China in November 1987, and authenticated by Prof. Y. Zhong. A voucher specimen has been deposited in the herbarium of our institute.
Extraction and isolation
were isolated from the Chinese medicinal plant
The dried and ground stems of A. gusanlung
Acangelisia gusanlung H. S. Lo (Menispermaceae). Their structures were elucidated mainly by spectro-
(20 kg) were refluxed with 95% EtOH. The extract was concentrated to dryness under reduced pressure below 60 °C. The residue
scopic analysis.
Key words Acangelisia gusanlung, Menispermaceae, 8-oxotetrahydroprotoberberine alkaloids.
Introduction Acangelisia gusanlung H. S. Lo (Menispermaceae) is used in the Chinese traditional medicine as an anti-inflammatory, an antipyretic, and for detoxication in southern China. No chemical studies on its constituents have been published so far. During chemical studies on the same genus, Toshinobu et al. (1) have isolated four new furanoditerpenes from A. flava, Garcia et al. (2) reported
the separation of three quaternary alkaloids from A. loureirii, and later Verpoorte et al. (3) reported the presence of six quaternary alkaloids and three tertiary alkaloids in A. flava. As a result of a search for new bioactive compo-
nents from A. gusanlung, two new 8-oxotetrahydroprotoberberine-type alkaloids, gusanlung A (1) and B (2), together with the known alkaloids, berberine and jatrorrhizine, were isolated from this plant. This is first report of 8-oxoprotoberberine-type alkaloids from the Acangelisia genus.
Materials and Methods Melting points were measured on a Kofler hot stage microscope and were uncorrected, UV spectra were recorded on a Shimadzu UV-250 apparatus. Optical rotations were taken on
a Perkin-Elmer model 241 polarimeter, JR spectra on a PerkinElmer 599B as KBr pellets, mass spectra on a MAT-711 or M-80 mass spectrometer. 'H-NMR and 13C-NMR spectra were recorded in DMSO-d6 or CDC13 on a Bruker-400 and AC-100 spectrometer. Silica gel 200—300 mesh and silica gel H for column chromatography, and silica gel GF-254 for TLC were produced by Qindao Haiyang Chemical Factory, China.
was partitioned between EtOAc and H20 (1 : 1, v/v). The EtOAc solution was evaporated to dryness and the solid was treated by the usual method (4) to yield crude alkaloids. 30 g of the crude alkaloids were chromatographed over a column (4.5 x 110cm) of silica gel (1.2kg) using a EtOAc/EtOH gradient as the eluent in 200-ml fractions. The fractions were combined based on the TLC profiles. The residue (1.5 g) from fractions 28—31 was rechromatographed on a silica gel H column (2.5 x 70cm) eluted with chloroform-methanol (80:4, v/v) to yield gusanlung A (30mg). The residue (1.7g) from fractions 20—23 was subjected to thin layer chromatography on a
preparative scale (0.5mm thickness) using chloroform-acetone (84 : 4, v/v) as solvent to yield gusanlung B (40 mg).
GusanlungA (1) Yellow needles, m.p. 260—262°C; la1: —395.5° (c 0.27, CHC13); UV max (EtOH) nm (log e): 226 (4.25), 260 (sh) (3.80), 296(3.83), 320(3.28); JR Vmax (KBr) cm: 3300, 1635. 1620, 1570, 1483, 1412, 1290, 1030; 1H-NMR (DMSO-d6) ô: 2.62 (dd, = 15.3 Hz, J1 = 13.3 Hz, 1H, H-13/3), 2.73—2.81 (m, 3H, 2 x H-5, H-6a), 3.13 (dd, Jib, i = 15.3 Hz, J1, = 3.1 Hz, 1H, H13a), 4.68 (dd, Jl = 13.3 Hz, Jii = 3.1 Hz, 1H,H-14a), 4.71 (m, 1H, H-6), 3.76 (s, 3H, OCH3), 5.98, 5.99 (s, 1H each, OCH2O), 6.80 (s, 1H, H-4), 6.96 (s, 1H, H-i), 6.86 (d, J= 8.1 Hz, 1H, H-12), 6.99(d, J= 8.1 Hz, 1H, H-il); 13C-NMR: see Table 1; EJMSm/z: 339 (M), 176. 174, 149, 135; Anal. calcd for C19H17NO5: C 67.47, H 5.13, N 4.34%; Found: C 67.31, H 5.01, N 4.13%.
Acetyl compound (Ia) of I 6mg of compound 1 were treated with acetic anhydride (0.6 ml) and pyridine (2 drops) at room temperature overnight. The reaction mixture was treated in the usual manner to
give the acetylgusanlung A (Ia) (5mg), m.p. 195—196°C; [a]6: —377°(cO.082, CHC13); IRv,jKBr)cm1: 1760,1645,1480,1210, 1040; ElMS m/z: 381 (M), 339, 321, 176, 174, 149, 135; 'H-NMR (CDC13) ô: 2.34 (s, 3H, OCOCH3), 2.73 (dd, J11 = 15.6 Hz, J11 = 13.1 Hz, 1H, H-13/3), 3.04 (dd, J11 15.6 Hz, = 3.0 Hz, lH, H-13a), 4.74 (dd, J1i = 13.1 Hz, J113, = 3.0Hz, 1H, H14a), 2.78—2.95 (m, 3H, 2 x H-5, H-6a), 3.94(s, 3H, OCH3), 5.94(s, 2H, OCH2O), 6.64 (s, 1H, H-4), 6.65 (s, 1H, H-i), 6.97 (d, J= 8.0 Hz, 1H, H-12), 7.13 (d,J= 8.0Hz, 1H, H-il).
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Abstract
458 Planta Med. 57(1991)
GusanlungB (2) Yellow needles, m.p. 224—226 °C; [a]1: — 348° (C 0.54, CHC13); UVAmax(EtOH)nm (log ): 228 (4.25), 260 (3.81), 296
(3.88), 320 (3.36); JR Vmax (KBr) cm1: 1636, 1570, 1475, 1416, 1265, 1230, 1035; 1H-NMR (CDC13) h: 2.74 (dd, J1 15.3 Hz, 13.2 Hz, 1H, H-1313), 2.98(dd, J1 i = 15.3 Hz, J131 = 3.2 Hz, 1H, H-13a), 2.80—2.96 (m, 3H, 2 x H-5, H-6a), 3.87, 3.99 = 13.2 Hz, = 3.2 Hz, (s, 3H each, 2 x OCH3), 4.68 (dd, Jll,
Ji =
1H, H-14a), 4.95 (m, 1H, H-6f3), 5.93 (s, 2H, OCH2O), 6.64 (s, 1H, H-
Jin-Sheng Zhang and Zhong-Liang Chen
phenolic groups must be located at C-i0 and C-9, respectively. If the protons with the AB pattern in the 1H-NMR spectrum were located at C-9 and C-b, the chemical shift of H-9 would be at more downfield because of the deshielding effect due to the presence of the carbonyl group at C-8 (8). However, no such evidence was observed.
0 .—i
4)
4), 6.65 (s, 1H, H-i), 6.91 (d, J 8.1 Hz, 1H, H-12), 6.98 (d, J = 8.1 Hz, 1H, H-li); 13C-NMR: see Table 1; ElMS m/z: 353 (Mt), 176,
174, 149, 135, 120; HRMS: 353.1271, calcd. for C20H19N05:
Il2i
353.1263.
la R ° COCH3
The molecular formula of gusanlung A, gusanlung A showed phenolic hydroxy (3300 cm-1), carbonyl (1635 cm1), and aromatic (1570, 1483 cm) bands. The absorption at 1635 cm suggested that 1 contained a
lactam carbonyl group, supported by the signal at ó = 161.4 ppm. In ElMS, a base peak showed at m/z 176, and this is a characteristic fragment produced by retro-DielsAlder cleavage of ring C in the tetrahydroprotoberberinetype alkaloids (5, 6). This fragment also suggested that the methylenedioxy group is located in the isoquinoline moiety. The ElMS gave a series of fragments corresponding to those
formed by the cleavage of tetrahydroprotoberberine-type alkaloids (5, 6). Hence, gusanlung A should be an 8-oxotetrahydroprotoberberine-type alkaloid. Moreover, its IJV spectrum was similar to that of this class alkaloids (7). The 1H-NMR spectrum of 1 exibited a threespin system by double irradiation experiments and 2D-1HNMR. In this system, each of the three protons appeared as
double doublets at O = 2.62 (J= 15.3, 13.3 Hz), 3.13 (J= 15.3, 3.1 Hz), and 4.68 ppm(J= 13.3, 3.1 Hz). The signal at 6 = 4.68 ppm was assigned to H-14a (8). In the molecular model of gusanlung A, H-14a has a 180° dihedral angle with H-13f3 and 45° angle with H-13a, indicating that signals at 6 = 2.62 and 3.13 ppmmustbe H-i3fiand H-13a, according to their i-values. In addition, 1H-NMR of compound I showed a one proton multiplet at 6 = 4.71 ppm due to H-
6f3 (8), and a three proton multiplet between 2.73— 2.81 ppm which was attributed to H-5 and H-6a, a methoxy singlet at 6 = 3.76 ppm, two proton singlets at 6 = 5.98 and 5.99 ppm due to the methylenedioxy group, two aromatic proton singlets at 6 = 6.80 and 6.97 ppm, two aromatic proton doublets with anAB pattern at 6 = 6.86 ppm(J= 8.1 Hz) and 6.99 ppm (J = 8.1 Hz). In order to elucidate the positions of the substitutions, an NOE difference study of the compound was carried out. A 1.89% enhancement of signals at 6 = 2.73—2.81 ppm, due to H-5, was observed on irradiation of the signal at 6.80 ppm, indicating that the signal at 6 = 6.80 ppm should be H-4. Irradiation of the signal at 6.96 ppm caused a 4.7% enhancement of the signal at 6 = 4.68 ppm (H-14a), implying that the signal at 6 = 6.96 ppm must be H-i. Similarly, a 3.6% NOE enhance-
ment of the signal at 6.99 ppm, a doublet of doublets with an AB pattern, appeared on irradiation of the methoxy singlet at 6= 3.76 ppm, showing that signals at 6.99 and 6.86 ppm should be H-il and H- 12, respectively. So, the methoxy and
2 R°CH3 Table 1 '3C-NMR spectra of gusanlung A and B (1 and 2). Carbon
GusanlungA
GusanlungB
1
106.1(d)
106.0(d)
2 3 4
145.9a(S) 147.7a(s)
146.6a(s)
4a 5 6
29.0 (t)
8 8a
9 10
107.8(d) l29.1b(5)
37.8(t) 161.4(s) 1223b(5) 149.7a(s)
11 12
145.7°(s) 118.9(d) 122.1(d)
12a
128.21(5)
13 14
37.7(t)
OCH3
54.4(d) 129.3'(s) 60.5(q)
OCH2O
100.5(t)
14a
146.7a(s) 108.5(d) 1286b(5) 29.8 (t) 39.1 (t)
162.5(s) 123.5(s)
153.0(s) 150.1(s) 115.4(d) 121.9(d) 1287b(5) 38.2(t) 55.2(d) 130.8b(5)
61.5(q), 56.2(q)
101.0(t)
Chemical shifts in ppm downfield from TMS, gusanlung A in DMSO-d5 and gusanlung B in CDCI3. ,b The assignments may be interchanged In any vertical column.
The proposed structure 1 was confirmed by its 13CNMR analysis (Table 1) and acetate derivatization. The 13C-NMR spectrum showed three methylene peaks at 6 = 29.0, 37.8, and 37.7 ppm due to C-5, C-6, and C-i3, respectively. Other distinctive signals included a methine (6 = 54.4 ppm), a methoxy (6 = 60.5 ppm), a methylenedioxy (6 = 100.5 ppm), a carbonyl (6 = i6i.4ppm) group, and 12 aromatic carbon atoms. Compound 1 was acetylated with acetic anhydride-pyridine to give the acetate Ia, establishing the presence of one phenolic hydroxy group.
Gusanlung B, C20H19NO5 (M, mlz found
353.1271; calcd 353.1263), has similar spectroscopic characteristics to those of compound 1. Its IR spectrum showed a carbonyl group at 1635 cm and no absorption band for a hydroxy group. The 'H-NMR spectrum of 2 was very similar to that of compound I with the exception of more one methoxy singlet than compound 1, and the signal of the methylenedioxy group appeared as a singlet. This alkaloid has a nearly same 13C-NMR spectrum pattern (Table 1) as that of 1. It showed two methoxy signals at 6 = 56.2 and 61.5 ppm, alactam carbonyl signal at 6 = 162.5 ppm, and a
Downloaded by: University of British Columbia. Copyrighted material.
C19H17N05, was derived from the ElMS (M 339), elemental analysis, and 13C-NMR data. In the JR absorption spectrum,
OCH3
1 R°H
Results and Discussion
Two New 8-Oxotetrahydroprotoberberine Alkaloids, GusanlungA and B. from Acangelisia gusanlung
Acknowledgements _______________________________________
References 1 2
We wish to thank Professor J. L. McLaughlin (Purdue University) for his grammatical correction in preparing this article. 6
8
Kunii, T., Kagei. K.. Kawakami, Y., Nagai, Y., Nezu, Y., Sato, 1. (1985) Chem. Pharm. Bull. 33, 479. Garcia, L. M., Jewers, K., Manchanda, A. H., Martnod. P.. Nabney. J., Robinson, F. V. (1970) Phytochemistry 9, 663. Verpoorte, R., Siwon, J., Van Essen, G. F. A., Tieken, M., Baerheim Svendsen, A. (1982) J. Nat. Prod. 45, 582. Zhang, J. S., Yu, H. G., Lin, L. Z., Chen, Z. L., Xu, R. S., Deng, S. S. (1988) Acta Chimica Sinica 46, 595. Chen, C. Y., Maclean, D. B. (1968) Can. J. Chem. 46, 2501. Yu, C. K., Maclean, D. B., Rodrigo, R. G. A., Manske, R. H. F. (1970) Can. J. Chem. 48, 3673. Lenz, G. R. (1974)J. Org. Chem. 39, 2849. Marsden, R., Maclean, B. D. (1984) Can. J. Chem. 62, 1397.
Downloaded by: University of British Columbia. Copyrighted material.
methylenedioxy peak at 6 = 100.9 ppm. These data are in agreement with structure 2.
Planta Med. 57(1991) 459
Two New 8-Oxotetrahydroprotoberberine Alkaloids, Gusanlung A and B, from Acangelisia gusanlung and Zhong-Liang Chen1 Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 319 Yue-Yang Road, Shanghai 200031, People's Republic of China 2 Address for correspondence fin-S heng Zhang
1.2
1
Received: June 27, 1990
Two new 8 -oxotetrahydroprotoberberine alkaloids, gusanlung A (1) and B (2), together with known
isoquinoline alkaloids, berberine and jatrorrhizine,
The plants of A. gusanlung were collected in the Hainan Province of China in November 1987, and authenticated by Prof. Y. Zhong. A voucher specimen has been deposited in the herbarium of our institute.
Extraction and isolation
were isolated from the Chinese medicinal plant
The dried and ground stems of A. gusanlung
Acangelisia gusanlung H. S. Lo (Menispermaceae). Their structures were elucidated mainly by spectro-
(20 kg) were refluxed with 95% EtOH. The extract was concentrated to dryness under reduced pressure below 60 °C. The residue
scopic analysis.
Key words Acangelisia gusanlung, Menispermaceae, 8-oxotetrahydroprotoberberine alkaloids.
Introduction Acangelisia gusanlung H. S. Lo (Menispermaceae) is used in the Chinese traditional medicine as an anti-inflammatory, an antipyretic, and for detoxication in southern China. No chemical studies on its constituents have been published so far. During chemical studies on the same genus, Toshinobu et al. (1) have isolated four new furanoditerpenes from A. flava, Garcia et al. (2) reported
the separation of three quaternary alkaloids from A. loureirii, and later Verpoorte et al. (3) reported the presence of six quaternary alkaloids and three tertiary alkaloids in A. flava. As a result of a search for new bioactive compo-
nents from A. gusanlung, two new 8-oxotetrahydroprotoberberine-type alkaloids, gusanlung A (1) and B (2), together with the known alkaloids, berberine and jatrorrhizine, were isolated from this plant. This is first report of 8-oxoprotoberberine-type alkaloids from the Acangelisia genus.
Materials and Methods Melting points were measured on a Kofler hot stage microscope and were uncorrected, UV spectra were recorded on a Shimadzu UV-250 apparatus. Optical rotations were taken on
a Perkin-Elmer model 241 polarimeter, JR spectra on a PerkinElmer 599B as KBr pellets, mass spectra on a MAT-711 or M-80 mass spectrometer. 'H-NMR and 13C-NMR spectra were recorded in DMSO-d6 or CDC13 on a Bruker-400 and AC-100 spectrometer. Silica gel 200—300 mesh and silica gel H for column chromatography, and silica gel GF-254 for TLC were produced by Qindao Haiyang Chemical Factory, China.
was partitioned between EtOAc and H20 (1 : 1, v/v). The EtOAc solution was evaporated to dryness and the solid was treated by the usual method (4) to yield crude alkaloids. 30 g of the crude alkaloids were chromatographed over a column (4.5 x 110cm) of silica gel (1.2kg) using a EtOAc/EtOH gradient as the eluent in 200-ml fractions. The fractions were combined based on the TLC profiles. The residue (1.5 g) from fractions 28—31 was rechromatographed on a silica gel H column (2.5 x 70cm) eluted with chloroform-methanol (80:4, v/v) to yield gusanlung A (30mg). The residue (1.7g) from fractions 20—23 was subjected to thin layer chromatography on a
preparative scale (0.5mm thickness) using chloroform-acetone (84 : 4, v/v) as solvent to yield gusanlung B (40 mg).
GusanlungA (1) Yellow needles, m.p. 260—262°C; la1: —395.5° (c 0.27, CHC13); UV max (EtOH) nm (log e): 226 (4.25), 260 (sh) (3.80), 296(3.83), 320(3.28); JR Vmax (KBr) cm: 3300, 1635. 1620, 1570, 1483, 1412, 1290, 1030; 1H-NMR (DMSO-d6) ô: 2.62 (dd, = 15.3 Hz, J1 = 13.3 Hz, 1H, H-13/3), 2.73—2.81 (m, 3H, 2 x H-5, H-6a), 3.13 (dd, Jib, i = 15.3 Hz, J1, = 3.1 Hz, 1H, H13a), 4.68 (dd, Jl = 13.3 Hz, Jii = 3.1 Hz, 1H,H-14a), 4.71 (m, 1H, H-6), 3.76 (s, 3H, OCH3), 5.98, 5.99 (s, 1H each, OCH2O), 6.80 (s, 1H, H-4), 6.96 (s, 1H, H-i), 6.86 (d, J= 8.1 Hz, 1H, H-12), 6.99(d, J= 8.1 Hz, 1H, H-il); 13C-NMR: see Table 1; EJMSm/z: 339 (M), 176. 174, 149, 135; Anal. calcd for C19H17NO5: C 67.47, H 5.13, N 4.34%; Found: C 67.31, H 5.01, N 4.13%.
Acetyl compound (Ia) of I 6mg of compound 1 were treated with acetic anhydride (0.6 ml) and pyridine (2 drops) at room temperature overnight. The reaction mixture was treated in the usual manner to
give the acetylgusanlung A (Ia) (5mg), m.p. 195—196°C; [a]6: —377°(cO.082, CHC13); IRv,jKBr)cm1: 1760,1645,1480,1210, 1040; ElMS m/z: 381 (M), 339, 321, 176, 174, 149, 135; 'H-NMR (CDC13) ô: 2.34 (s, 3H, OCOCH3), 2.73 (dd, J11 = 15.6 Hz, J11 = 13.1 Hz, 1H, H-13/3), 3.04 (dd, J11 15.6 Hz, = 3.0 Hz, lH, H-13a), 4.74 (dd, J1i = 13.1 Hz, J113, = 3.0Hz, 1H, H14a), 2.78—2.95 (m, 3H, 2 x H-5, H-6a), 3.94(s, 3H, OCH3), 5.94(s, 2H, OCH2O), 6.64 (s, 1H, H-4), 6.65 (s, 1H, H-i), 6.97 (d, J= 8.0 Hz, 1H, H-12), 7.13 (d,J= 8.0Hz, 1H, H-il).
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Abstract
458 Planta Med. 57(1991)
GusanlungB (2) Yellow needles, m.p. 224—226 °C; [a]1: — 348° (C 0.54, CHC13); UVAmax(EtOH)nm (log ): 228 (4.25), 260 (3.81), 296
(3.88), 320 (3.36); JR Vmax (KBr) cm1: 1636, 1570, 1475, 1416, 1265, 1230, 1035; 1H-NMR (CDC13) h: 2.74 (dd, J1 15.3 Hz, 13.2 Hz, 1H, H-1313), 2.98(dd, J1 i = 15.3 Hz, J131 = 3.2 Hz, 1H, H-13a), 2.80—2.96 (m, 3H, 2 x H-5, H-6a), 3.87, 3.99 = 13.2 Hz, = 3.2 Hz, (s, 3H each, 2 x OCH3), 4.68 (dd, Jll,
Ji =
1H, H-14a), 4.95 (m, 1H, H-6f3), 5.93 (s, 2H, OCH2O), 6.64 (s, 1H, H-
Jin-Sheng Zhang and Zhong-Liang Chen
phenolic groups must be located at C-i0 and C-9, respectively. If the protons with the AB pattern in the 1H-NMR spectrum were located at C-9 and C-b, the chemical shift of H-9 would be at more downfield because of the deshielding effect due to the presence of the carbonyl group at C-8 (8). However, no such evidence was observed.
0 .—i
4)
4), 6.65 (s, 1H, H-i), 6.91 (d, J 8.1 Hz, 1H, H-12), 6.98 (d, J = 8.1 Hz, 1H, H-li); 13C-NMR: see Table 1; ElMS m/z: 353 (Mt), 176,
174, 149, 135, 120; HRMS: 353.1271, calcd. for C20H19N05:
Il2i
353.1263.
la R ° COCH3
The molecular formula of gusanlung A, gusanlung A showed phenolic hydroxy (3300 cm-1), carbonyl (1635 cm1), and aromatic (1570, 1483 cm) bands. The absorption at 1635 cm suggested that 1 contained a
lactam carbonyl group, supported by the signal at ó = 161.4 ppm. In ElMS, a base peak showed at m/z 176, and this is a characteristic fragment produced by retro-DielsAlder cleavage of ring C in the tetrahydroprotoberberinetype alkaloids (5, 6). This fragment also suggested that the methylenedioxy group is located in the isoquinoline moiety. The ElMS gave a series of fragments corresponding to those
formed by the cleavage of tetrahydroprotoberberine-type alkaloids (5, 6). Hence, gusanlung A should be an 8-oxotetrahydroprotoberberine-type alkaloid. Moreover, its IJV spectrum was similar to that of this class alkaloids (7). The 1H-NMR spectrum of 1 exibited a threespin system by double irradiation experiments and 2D-1HNMR. In this system, each of the three protons appeared as
double doublets at O = 2.62 (J= 15.3, 13.3 Hz), 3.13 (J= 15.3, 3.1 Hz), and 4.68 ppm(J= 13.3, 3.1 Hz). The signal at 6 = 4.68 ppm was assigned to H-14a (8). In the molecular model of gusanlung A, H-14a has a 180° dihedral angle with H-13f3 and 45° angle with H-13a, indicating that signals at 6 = 2.62 and 3.13 ppmmustbe H-i3fiand H-13a, according to their i-values. In addition, 1H-NMR of compound I showed a one proton multiplet at 6 = 4.71 ppm due to H-
6f3 (8), and a three proton multiplet between 2.73— 2.81 ppm which was attributed to H-5 and H-6a, a methoxy singlet at 6 = 3.76 ppm, two proton singlets at 6 = 5.98 and 5.99 ppm due to the methylenedioxy group, two aromatic proton singlets at 6 = 6.80 and 6.97 ppm, two aromatic proton doublets with anAB pattern at 6 = 6.86 ppm(J= 8.1 Hz) and 6.99 ppm (J = 8.1 Hz). In order to elucidate the positions of the substitutions, an NOE difference study of the compound was carried out. A 1.89% enhancement of signals at 6 = 2.73—2.81 ppm, due to H-5, was observed on irradiation of the signal at 6.80 ppm, indicating that the signal at 6 = 6.80 ppm should be H-4. Irradiation of the signal at 6.96 ppm caused a 4.7% enhancement of the signal at 6 = 4.68 ppm (H-14a), implying that the signal at 6 = 6.96 ppm must be H-i. Similarly, a 3.6% NOE enhance-
ment of the signal at 6.99 ppm, a doublet of doublets with an AB pattern, appeared on irradiation of the methoxy singlet at 6= 3.76 ppm, showing that signals at 6.99 and 6.86 ppm should be H-il and H- 12, respectively. So, the methoxy and
2 R°CH3 Table 1 '3C-NMR spectra of gusanlung A and B (1 and 2). Carbon
GusanlungA
GusanlungB
1
106.1(d)
106.0(d)
2 3 4
145.9a(S) 147.7a(s)
146.6a(s)
4a 5 6
29.0 (t)
8 8a
9 10
107.8(d) l29.1b(5)
37.8(t) 161.4(s) 1223b(5) 149.7a(s)
11 12
145.7°(s) 118.9(d) 122.1(d)
12a
128.21(5)
13 14
37.7(t)
OCH3
54.4(d) 129.3'(s) 60.5(q)
OCH2O
100.5(t)
14a
146.7a(s) 108.5(d) 1286b(5) 29.8 (t) 39.1 (t)
162.5(s) 123.5(s)
153.0(s) 150.1(s) 115.4(d) 121.9(d) 1287b(5) 38.2(t) 55.2(d) 130.8b(5)
61.5(q), 56.2(q)
101.0(t)
Chemical shifts in ppm downfield from TMS, gusanlung A in DMSO-d5 and gusanlung B in CDCI3. ,b The assignments may be interchanged In any vertical column.
The proposed structure 1 was confirmed by its 13CNMR analysis (Table 1) and acetate derivatization. The 13C-NMR spectrum showed three methylene peaks at 6 = 29.0, 37.8, and 37.7 ppm due to C-5, C-6, and C-i3, respectively. Other distinctive signals included a methine (6 = 54.4 ppm), a methoxy (6 = 60.5 ppm), a methylenedioxy (6 = 100.5 ppm), a carbonyl (6 = i6i.4ppm) group, and 12 aromatic carbon atoms. Compound 1 was acetylated with acetic anhydride-pyridine to give the acetate Ia, establishing the presence of one phenolic hydroxy group.
Gusanlung B, C20H19NO5 (M, mlz found
353.1271; calcd 353.1263), has similar spectroscopic characteristics to those of compound 1. Its IR spectrum showed a carbonyl group at 1635 cm and no absorption band for a hydroxy group. The 'H-NMR spectrum of 2 was very similar to that of compound I with the exception of more one methoxy singlet than compound 1, and the signal of the methylenedioxy group appeared as a singlet. This alkaloid has a nearly same 13C-NMR spectrum pattern (Table 1) as that of 1. It showed two methoxy signals at 6 = 56.2 and 61.5 ppm, alactam carbonyl signal at 6 = 162.5 ppm, and a
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C19H17N05, was derived from the ElMS (M 339), elemental analysis, and 13C-NMR data. In the JR absorption spectrum,
OCH3
1 R°H
Results and Discussion
Two New 8-Oxotetrahydroprotoberberine Alkaloids, GusanlungA and B. from Acangelisia gusanlung
Acknowledgements _______________________________________
References 1 2
We wish to thank Professor J. L. McLaughlin (Purdue University) for his grammatical correction in preparing this article. 6
8
Kunii, T., Kagei. K.. Kawakami, Y., Nagai, Y., Nezu, Y., Sato, 1. (1985) Chem. Pharm. Bull. 33, 479. Garcia, L. M., Jewers, K., Manchanda, A. H., Martnod. P.. Nabney. J., Robinson, F. V. (1970) Phytochemistry 9, 663. Verpoorte, R., Siwon, J., Van Essen, G. F. A., Tieken, M., Baerheim Svendsen, A. (1982) J. Nat. Prod. 45, 582. Zhang, J. S., Yu, H. G., Lin, L. Z., Chen, Z. L., Xu, R. S., Deng, S. S. (1988) Acta Chimica Sinica 46, 595. Chen, C. Y., Maclean, D. B. (1968) Can. J. Chem. 46, 2501. Yu, C. K., Maclean, D. B., Rodrigo, R. G. A., Manske, R. H. F. (1970) Can. J. Chem. 48, 3673. Lenz, G. R. (1974)J. Org. Chem. 39, 2849. Marsden, R., Maclean, B. D. (1984) Can. J. Chem. 62, 1397.
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methylenedioxy peak at 6 = 100.9 ppm. These data are in agreement with structure 2.
Planta Med. 57(1991) 459
