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Pyrrolizidine alkaloids from Senecio kaschkarovii
Phytochemistry, Vol. 31, No. 10, pp. 3671-3672, Printed in Great Britain.
PYRROLIZIDINE
1992
003 1 9422/92 $5.00 + 0.00 Q 1992 Pergamon Press Ltd
ALKALOIDS
DONG-LIANG
CHENG,*
FROM SENECZO KASCHKAROVII JIN-KUI
NIU
and E. RoEDERt
Institute of Organic Chemistry, Lanzhou University National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, People’s Republic of China; TInstitute fur Pharmazeutische Chemie, Universitat Bonn, D-5300 Bonn 1, F.R.G. (Received in revised form 26 February 1992) Key Word Index-Senecio kaschkarovii; Compositae; pyrrolizidine alkaloids; triangularine; neotriangularine; 7senecioyl-9-sarracinoyl retronecine; neosarracine.
Abstract-Four neotriangularine,
pyrrolizidine alkaloids were isolated from Senecio kaschkarovii and identified as triangularine, 7-senecioyl-9-sarracinoyl retronecine and neosarracine, of which the last was a new one.
INTRODUCTION
Pyrrolizidine alkaloids are widespread in the genus Seneand carcinogenic effects of this genus. Recently we investigated the chemical constituents of Senecio kaschkarovii C. Winkl. growing in Zhang County, Gansu Province of China, which had not been studied previously. Four pyrrolizidine alkaloids, of which one was new, were isolated and their structures were identified by spectroscopic methods.
cio. They are responsible for the heptatotoxic
BFSUL’l%AND
DISCUSSION
The crude alkaloids were obtained from methanolic extracts after normal procedures [l-3]. They were separated by silica gel column chromatography and preparative TLC to give four pyrrolizidine alkaloids, l-4. Mass spectra and elemental analyses gave the formulae C,,H,,O,N for 1-3, and C,sH,,OSN for 4. The ‘HNMR and 13CNMR data of alkaloids l-3 were completely consistent with those reported [4-73 previously for triangularine (l), neotriangularine (2) and 7senecioyl-9-sarracinoyl retronecine (3), respectively; the EI-mass spectra supported the results inferred above C7, 81. Comparison of the ‘H NMR and “CNMR data of alkaloid 4 with those reported for sarracine [4, S], showed that the only difference between the two was in the nature of the acid ester at C-9. Thus, alkaloid 4 was determined to be 7-[(Z)-2-methylbut-2-enoyl]-9-[(E)-hydroxymethylbut-2-enoyl]-platynecine, namely neosarracine. The acid [(E)-2-hydroxymethyl-2-butenoic neosarracinic acid] positioned at C-9 in neosarracine was different from the sarracinic acid C(Z)-2-hydroxymethyl-2-butenoic acid] ester only in the configurations; they can be easily differentiated from their markedly different ‘HNMR signals, mainly in the chemical shifts of the vinyl proton (H-17), the methyl proton (H-18) and the hydroxymethyl proton (H-19) [4]. The chemical shift of H-17 in neosarracinic acid ester was downfield from that in sarracinic
acid ester with shift differences of 0.5 ppm or greater, because of the deshielding effect of the carbonyl group at C-16 on H-17. The signal of the hydroxymethyl proton was 0.11 ppm downfield from that in sarracinic acid ester, and the signal of the methyl 0.15 ppm upfield because of the same reason. The chemical shifts of 6.97, 1.92 and 4.35 ppm, observed for alkaloid 4 for H-17, H-18, H-19 respectively, corresponded with those of 6.95, 1.90 and 4.33 ppm, respectively, for H-17, H-18 and H-19 reported for neotriangularine [4], and differed considerably from those of 6.38,2.05 and 4.22 ppm for H-17, H-18 and H-19, respectively, reported for sarracine [6]. Assignments of ’ 3C NMR signals further established the structure inferred from the ‘H NMR data of alkaloid 4. The 13CNMR chemical shifts of alkaloid 4 were in close agreement with values reported for sarracine [S], except for the acid ester at C-9. The main difference was in the signals for the methyl and hydroxymethyl carbons (C18 and C-19). The chemical shifts of these carbon atoms in neosarracinic acid ester were 8 ppm and 1 ppm upfield, respectively, from those in sarracinic acid ester because of the reason mentioned above. The chemical shifts of 14.3 and 56.6 ppm for C-19 and C-18, obtained for alkaloid 4, corresponded with those of 14.2 and 56.7 ppm for C-19 and C-18 in neotriangularine [4], but differed considerably from those of 15.7 and 64.9 ppm for C-19 and C-18 in the sarracinic acid ester reported for sarracine [S]. The EI-mass spectrum of alkaloid 4 had a typical fragmentation pattern in the mass range between m/z 139 and 82, characteristic of platynecine or its isomeric forms. In addition, other peaks were essentially consistent with those reported previously for sarracine. The observation of weak peaks at m/z 237 resulting from C-9-O cleavage and the loss of the peaks at m/z 221 (C-7-O cleavage) and nr/z 238 (C-9-O cleavage) establishes that the neosarracinic acid is definitely positioned at C-9 and the angelic acid at C-7. Thus, we concluded that alkaloid 4 is a new natural product, namely neosarracine. EXPERIMENTAL
General. EIMS were measured at 70 eV (180”). ‘H NMR and
*Author to whom correspondence should be addressed.
“CNMR 3671
spectra were obtained at 400 MHz and 100 MHz,
Short Reports
3672
R’
R2
H
Me
: triangularine
Me
H
: neotriangulorine
1
3 2
respectively; samples (10 mg) were dissolved in 0.4 ml CDCI, and values are in ppm with TMS as int. standard. Extraction and isolation. Plant material was collected from Zhang County, Gansu province, P.R. China and was identified by Prof. Ru-Neng Zhao, Dept of Pharmacy, Lanzhou Medical College. Air-dried and powdered material (8.5 kg) was extracted x 3 with hot EtOH and then filtered. The comb. filtrates were then coned under red. pres. The coned residue was dissolved x 3 in 2% HCI (pH ca 2-3), and the mixt. extracted x 5 with an equal vol. of CHzCl,. The aq. phase was adjusted to pH ca 9-10 with coned NH,OH and extracted x 5 with an equal vol. of CHzCl,. Evapn of the CHzCl, extracts gave ca 10 g of an oil, the crude alkaloids. The total crude alkaloids were chromatographed on a silica gel column (200-300 mesh, 500 g) with CHzCIz-MeOH gradients, to give four frs. Frs I-IV gave alkaloids 1-4, respectively, after further CC and prep. TLC. Alkaloid 1. Oil. [xl;‘= f6.0 (EtOH; c 1.10). IR v!$!; cm-‘: 3388 (OH), 1735 (satd ester), 1718 (unsatd ester), 1600 (C=C). Elemental analysis: calcd for C,,H,sO,N, C:64.48; H:7.46. Found C:64.70; 64.31, H:7.72; 7.58. EIMS m/z (rel. int.): 55 (90), 80 (35), 83 (lOO), 93 (40) 94 (40), 119 (25), 120 (30), 136 (55), 138 (65), 154 (6), 220 (14). 237 (30), 335 (2). ‘H NMR: 1.80 (3H, s, H14), 1.97 (3H, d, 5=6.8 Hz, H-13), 2.05 (3H, d, 5=7.3 Hz, H-18) 1.80-2.10 (2H, m, H-6), 2.90 (lH, m, H-5,), 3.68 (2H, m, H-3, and H-53, 3.95 (lH, m, H-3,), 4.23 (2H, s, H-19), 4.58 (lH, m, H-8), 4.67 (lH, d, J= 14 Hz, H-9u), 4.84 (lH, d, J= 14 Hz, H-9d), 5.05 (lH, br s, H-7), 5.80 (lH, m, H-2), 6.17 (lH, 4. 5=7.0 Hz, H-12), 6.39 (lH, 4, J=7.1 Hz, H-17). Alkaloid 2. Oil. [G(]:’ = + 3.2 (EtOH; c 0.5). IR v:t; cm-‘: 3322 (OH), 1740 (satd ester), 1718 (unsatd ester), 1610 (C=C). Elemental analysis: calcd for C,,H,,O,N, C:64.48, H: 7.46. Found C: 64.79; 64.30, H: 7.81; 7.40. EIMS m/z (rel. int.): 55 (45), 80 (28), 83 (75), 93 (100) 94 (61), 119 (29), 120 (44) 136 (92), 137 (lo), 219 (6), 220 (14), 237 (11) 335 (1). ‘H NMR: 1.83 (3H, s, H14), 1.99 (3H, d, 5=7.0 Hz, H-18) 2.04 (3H, d, 5=6.8 Hz, H-13), 2.30(2H,m,H-6),2.46(1H,m,H-5sk3.11 (lH,m,H-3&,3.80(1H, br s, H-5,), 3.83 (lH, br s, H-3,), 4.35 (2H, s, H-19), 4.59 (lH, d, J = 14 HZ, H-9u), 4.78 (lH, d, J= 14 Hz, H-9d), 4.80 (lH, m, H-8), 5.27(1H,brs,H-7),5.89(1H,brs,H-2),6.21(1H,q,J=7.6Hz,H12), 6.90 (lH, m, H-17). ‘sCNMR: 14.4 (C-18), 15.9 (C-14), 20.3 (C-13), 33.9 (C-6), 53.9 (C-5), 56.1 (C-19) 59.6 (C-9), 60.8 (C-3), 71.8 (C-7), 76.7 (C-8), 123.9(C-2), 126.2(C-Ilk 131.6(C-16). 133.2 (C-l), 141.7 (C-12) 142.7 (C-17), 165.6 (C-15). 166.7 (C-10). Alkaloid 3. Oil. [a];‘= + 50.5 (EtOH; c 1.0). IR YE; cm-i: 3399 (OH), 1730 (satd ester), 1716 (unsatd ester), 1620 (C=C). Elemental analysis: calcd for C 1s H 250 5N, C: 64.48, H:7.46. Found C: 65.00; 64.82, H: 7.80; 7.52. EIMS m/z (rel. int.): 80 (25), 83 (100) 93 (55), 94 (50) 119 (20). 120 (25). 136 (60) 220 (12) 219
R’
R2
Me
H
: neosarracine
H
Me
: sarracine
4
5
(5), 235 (3), 236 (3), 237 (lo), 335 (2). ‘HNMR: 1.90 (3H, d, J =l.OHz, H-13), 2.06 (3H, d, J=7.2Hz, H-18), 2.14 (3H, d, J = 1.0 Hz, H-14), 2.17 (2H, m, H-6), 2.74 (lH, m, H-5,), 3.45 (lH, m, H-5,) 3.48 (lH, m, H-3,). 4.08 (lH, d, .I= 15 Hz, H-3,) 4.22 (2H, s, H-19), 4.60 (lH, m, H-8), 4.70 (lH, d, J= 15.4 Hz, H-9u), 4.82(1H, d, J=15.1 Hz, H-9d), 5.44(1H, t like, H-7), 5.6O(lH, t like, H-11) 5.80 (lH, s, H-2), 6.38 (lH, 4, 3=7.3 Hz, H-17). “C NMR: 15.8 (C-18), 20.4 (C-14). 27.5 (C-13), 34.3 (C-6), 53.4 (C-5). 60.2 (C-9), 61.8 (C-3), 65.6 (C-19), 72.5 (C-7), 75.5 (C-8), 115.5 (C-11), 126.6 (C-2), 131.8 (C-16). 133.7 (C-l), 141.7 (C-17) 158.5 (C-12), 165.5 (C-15), 166.7 (C-10). Alkaloid 4. Oil. [a]:‘= +60.5 (EtOH; c 0.5). IR ~2: cm-‘: 3356 (OH), 1717 (ester), 1650 (C=C). Elemental analysis: calcd for C,sHz,O,N, C:64.09, H:8.01. Found C:64.30; 64.00, H: 8.10: 7.80. EIMS m/z (rel. int.): 55 (lOO), 82 (51), 83 (60), 94 (7), 95 (19). 97 (8), 122 (30), 138 (53). 222 (6), 237 (6), 337 (0.5). ‘HNMR: 1.92 (3H, d, 5=7.0 Hz, H-18), 1.93 (3H, d, J= 1.0 Hz, H-14) 2.02 (3H, d, J=7.0 Hz, H-13), 180-2.15 (4H, m, H-2 and H-6), 2.84 (2H, m, H-l and H-3,). 2.93 (lH, m, H-5,), 3.38 (lH, m, H-3,) 3.57 (lH, m, H-5,). 3.88 (lH, m, H-8), 4.28 (lH, 4, J =7.0 Hz,H-9u),4.35(2H,s, H-19),4.41 (lH,q,J=7.1 Hz,H-9d), 5.44 (lH, br s, H-7), 6.16 (lH, q, J=6.9 Hz, H-12), 6.97 (lH, q. J =7.5 Hz, H-17). ‘aCNMR: 14.3 (C-18), 15.9 (C-14), 20.8 (C-13), 28.7 (C-2), 34.8 (C-6), 40.0 (C-4), 53.5 (C-5), 54.6 (C-3), 56.6 (C-19), 63.2 (C-9), 68.9 (C-7), 74.7 (C-8), 126.6 (C-11). 131.8 (C-16) 140.7 (C-12), 140.8 (C-17), 166.4 (C-15). 166.7 (C-10). Acknowledgements This work was supported by the foundation of the Natural Science of China. We thank the Analytic Center, Lanzhou University, for their enthusiastic help and for elemental analysis.
REFERENCES
1. Bull, L. B., Culvenor, C. C. J. and Dick. A. T. (1968) The Pyrrolizidine Alkaloids. North-Holland, Amsterdam. 2. Mattocks, A. R. (1986) Chemistry and Toxicology ofPyrrolizidine Alkaloids, p. 24. Academic Press, London. 3. Rizk, A.-F. M. (1991) Naturally Occurring Pyrrolizidine Alkaloids. CRC Press, Boca Raton. 4. Roitman, J. N. (1983) Aust. .I. Chem. 36, 1203. 5. Rueger, H. and Benn, M. H. (1983) Can. J. Chem. 61,2526. 6. Roby, M. R. and Stermitz, F. R. (1984) J. Nat. Prod. 47, 846. 7. Roeder, E., Wiedenfeld, H. and Britz-Kirstgen, R. (1984) Phytochemistry 23, 1761. 8. Roeder, E., Wiedenfeld, H. and Schraut, R. (1984) Phytochemistry 23, 2125.
PYRROLIZIDINE
1992
003 1 9422/92 $5.00 + 0.00 Q 1992 Pergamon Press Ltd
ALKALOIDS
DONG-LIANG
CHENG,*
FROM SENECZO KASCHKAROVII JIN-KUI
NIU
and E. RoEDERt
Institute of Organic Chemistry, Lanzhou University National Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, People’s Republic of China; TInstitute fur Pharmazeutische Chemie, Universitat Bonn, D-5300 Bonn 1, F.R.G. (Received in revised form 26 February 1992) Key Word Index-Senecio kaschkarovii; Compositae; pyrrolizidine alkaloids; triangularine; neotriangularine; 7senecioyl-9-sarracinoyl retronecine; neosarracine.
Abstract-Four neotriangularine,
pyrrolizidine alkaloids were isolated from Senecio kaschkarovii and identified as triangularine, 7-senecioyl-9-sarracinoyl retronecine and neosarracine, of which the last was a new one.
INTRODUCTION
Pyrrolizidine alkaloids are widespread in the genus Seneand carcinogenic effects of this genus. Recently we investigated the chemical constituents of Senecio kaschkarovii C. Winkl. growing in Zhang County, Gansu Province of China, which had not been studied previously. Four pyrrolizidine alkaloids, of which one was new, were isolated and their structures were identified by spectroscopic methods.
cio. They are responsible for the heptatotoxic
BFSUL’l%AND
DISCUSSION
The crude alkaloids were obtained from methanolic extracts after normal procedures [l-3]. They were separated by silica gel column chromatography and preparative TLC to give four pyrrolizidine alkaloids, l-4. Mass spectra and elemental analyses gave the formulae C,,H,,O,N for 1-3, and C,sH,,OSN for 4. The ‘HNMR and 13CNMR data of alkaloids l-3 were completely consistent with those reported [4-73 previously for triangularine (l), neotriangularine (2) and 7senecioyl-9-sarracinoyl retronecine (3), respectively; the EI-mass spectra supported the results inferred above C7, 81. Comparison of the ‘H NMR and “CNMR data of alkaloid 4 with those reported for sarracine [4, S], showed that the only difference between the two was in the nature of the acid ester at C-9. Thus, alkaloid 4 was determined to be 7-[(Z)-2-methylbut-2-enoyl]-9-[(E)-hydroxymethylbut-2-enoyl]-platynecine, namely neosarracine. The acid [(E)-2-hydroxymethyl-2-butenoic neosarracinic acid] positioned at C-9 in neosarracine was different from the sarracinic acid C(Z)-2-hydroxymethyl-2-butenoic acid] ester only in the configurations; they can be easily differentiated from their markedly different ‘HNMR signals, mainly in the chemical shifts of the vinyl proton (H-17), the methyl proton (H-18) and the hydroxymethyl proton (H-19) [4]. The chemical shift of H-17 in neosarracinic acid ester was downfield from that in sarracinic
acid ester with shift differences of 0.5 ppm or greater, because of the deshielding effect of the carbonyl group at C-16 on H-17. The signal of the hydroxymethyl proton was 0.11 ppm downfield from that in sarracinic acid ester, and the signal of the methyl 0.15 ppm upfield because of the same reason. The chemical shifts of 6.97, 1.92 and 4.35 ppm, observed for alkaloid 4 for H-17, H-18, H-19 respectively, corresponded with those of 6.95, 1.90 and 4.33 ppm, respectively, for H-17, H-18 and H-19 reported for neotriangularine [4], and differed considerably from those of 6.38,2.05 and 4.22 ppm for H-17, H-18 and H-19, respectively, reported for sarracine [6]. Assignments of ’ 3C NMR signals further established the structure inferred from the ‘H NMR data of alkaloid 4. The 13CNMR chemical shifts of alkaloid 4 were in close agreement with values reported for sarracine [S], except for the acid ester at C-9. The main difference was in the signals for the methyl and hydroxymethyl carbons (C18 and C-19). The chemical shifts of these carbon atoms in neosarracinic acid ester were 8 ppm and 1 ppm upfield, respectively, from those in sarracinic acid ester because of the reason mentioned above. The chemical shifts of 14.3 and 56.6 ppm for C-19 and C-18, obtained for alkaloid 4, corresponded with those of 14.2 and 56.7 ppm for C-19 and C-18 in neotriangularine [4], but differed considerably from those of 15.7 and 64.9 ppm for C-19 and C-18 in the sarracinic acid ester reported for sarracine [S]. The EI-mass spectrum of alkaloid 4 had a typical fragmentation pattern in the mass range between m/z 139 and 82, characteristic of platynecine or its isomeric forms. In addition, other peaks were essentially consistent with those reported previously for sarracine. The observation of weak peaks at m/z 237 resulting from C-9-O cleavage and the loss of the peaks at m/z 221 (C-7-O cleavage) and nr/z 238 (C-9-O cleavage) establishes that the neosarracinic acid is definitely positioned at C-9 and the angelic acid at C-7. Thus, we concluded that alkaloid 4 is a new natural product, namely neosarracine. EXPERIMENTAL
General. EIMS were measured at 70 eV (180”). ‘H NMR and
*Author to whom correspondence should be addressed.
“CNMR 3671
spectra were obtained at 400 MHz and 100 MHz,
Short Reports
3672
R’
R2
H
Me
: triangularine
Me
H
: neotriangulorine
1
3 2
respectively; samples (10 mg) were dissolved in 0.4 ml CDCI, and values are in ppm with TMS as int. standard. Extraction and isolation. Plant material was collected from Zhang County, Gansu province, P.R. China and was identified by Prof. Ru-Neng Zhao, Dept of Pharmacy, Lanzhou Medical College. Air-dried and powdered material (8.5 kg) was extracted x 3 with hot EtOH and then filtered. The comb. filtrates were then coned under red. pres. The coned residue was dissolved x 3 in 2% HCI (pH ca 2-3), and the mixt. extracted x 5 with an equal vol. of CHzCl,. The aq. phase was adjusted to pH ca 9-10 with coned NH,OH and extracted x 5 with an equal vol. of CHzCl,. Evapn of the CHzCl, extracts gave ca 10 g of an oil, the crude alkaloids. The total crude alkaloids were chromatographed on a silica gel column (200-300 mesh, 500 g) with CHzCIz-MeOH gradients, to give four frs. Frs I-IV gave alkaloids 1-4, respectively, after further CC and prep. TLC. Alkaloid 1. Oil. [xl;‘= f6.0 (EtOH; c 1.10). IR v!$!; cm-‘: 3388 (OH), 1735 (satd ester), 1718 (unsatd ester), 1600 (C=C). Elemental analysis: calcd for C,,H,sO,N, C:64.48; H:7.46. Found C:64.70; 64.31, H:7.72; 7.58. EIMS m/z (rel. int.): 55 (90), 80 (35), 83 (lOO), 93 (40) 94 (40), 119 (25), 120 (30), 136 (55), 138 (65), 154 (6), 220 (14). 237 (30), 335 (2). ‘H NMR: 1.80 (3H, s, H14), 1.97 (3H, d, 5=6.8 Hz, H-13), 2.05 (3H, d, 5=7.3 Hz, H-18) 1.80-2.10 (2H, m, H-6), 2.90 (lH, m, H-5,), 3.68 (2H, m, H-3, and H-53, 3.95 (lH, m, H-3,), 4.23 (2H, s, H-19), 4.58 (lH, m, H-8), 4.67 (lH, d, J= 14 Hz, H-9u), 4.84 (lH, d, J= 14 Hz, H-9d), 5.05 (lH, br s, H-7), 5.80 (lH, m, H-2), 6.17 (lH, 4. 5=7.0 Hz, H-12), 6.39 (lH, 4, J=7.1 Hz, H-17). Alkaloid 2. Oil. [G(]:’ = + 3.2 (EtOH; c 0.5). IR v:t; cm-‘: 3322 (OH), 1740 (satd ester), 1718 (unsatd ester), 1610 (C=C). Elemental analysis: calcd for C,,H,,O,N, C:64.48, H: 7.46. Found C: 64.79; 64.30, H: 7.81; 7.40. EIMS m/z (rel. int.): 55 (45), 80 (28), 83 (75), 93 (100) 94 (61), 119 (29), 120 (44) 136 (92), 137 (lo), 219 (6), 220 (14), 237 (11) 335 (1). ‘H NMR: 1.83 (3H, s, H14), 1.99 (3H, d, 5=7.0 Hz, H-18) 2.04 (3H, d, 5=6.8 Hz, H-13), 2.30(2H,m,H-6),2.46(1H,m,H-5sk3.11 (lH,m,H-3&,3.80(1H, br s, H-5,), 3.83 (lH, br s, H-3,), 4.35 (2H, s, H-19), 4.59 (lH, d, J = 14 HZ, H-9u), 4.78 (lH, d, J= 14 Hz, H-9d), 4.80 (lH, m, H-8), 5.27(1H,brs,H-7),5.89(1H,brs,H-2),6.21(1H,q,J=7.6Hz,H12), 6.90 (lH, m, H-17). ‘sCNMR: 14.4 (C-18), 15.9 (C-14), 20.3 (C-13), 33.9 (C-6), 53.9 (C-5), 56.1 (C-19) 59.6 (C-9), 60.8 (C-3), 71.8 (C-7), 76.7 (C-8), 123.9(C-2), 126.2(C-Ilk 131.6(C-16). 133.2 (C-l), 141.7 (C-12) 142.7 (C-17), 165.6 (C-15). 166.7 (C-10). Alkaloid 3. Oil. [a];‘= + 50.5 (EtOH; c 1.0). IR YE; cm-i: 3399 (OH), 1730 (satd ester), 1716 (unsatd ester), 1620 (C=C). Elemental analysis: calcd for C 1s H 250 5N, C: 64.48, H:7.46. Found C: 65.00; 64.82, H: 7.80; 7.52. EIMS m/z (rel. int.): 80 (25), 83 (100) 93 (55), 94 (50) 119 (20). 120 (25). 136 (60) 220 (12) 219
R’
R2
Me
H
: neosarracine
H
Me
: sarracine
4
5
(5), 235 (3), 236 (3), 237 (lo), 335 (2). ‘HNMR: 1.90 (3H, d, J =l.OHz, H-13), 2.06 (3H, d, J=7.2Hz, H-18), 2.14 (3H, d, J = 1.0 Hz, H-14), 2.17 (2H, m, H-6), 2.74 (lH, m, H-5,), 3.45 (lH, m, H-5,) 3.48 (lH, m, H-3,). 4.08 (lH, d, .I= 15 Hz, H-3,) 4.22 (2H, s, H-19), 4.60 (lH, m, H-8), 4.70 (lH, d, J= 15.4 Hz, H-9u), 4.82(1H, d, J=15.1 Hz, H-9d), 5.44(1H, t like, H-7), 5.6O(lH, t like, H-11) 5.80 (lH, s, H-2), 6.38 (lH, 4, 3=7.3 Hz, H-17). “C NMR: 15.8 (C-18), 20.4 (C-14). 27.5 (C-13), 34.3 (C-6), 53.4 (C-5). 60.2 (C-9), 61.8 (C-3), 65.6 (C-19), 72.5 (C-7), 75.5 (C-8), 115.5 (C-11), 126.6 (C-2), 131.8 (C-16). 133.7 (C-l), 141.7 (C-17) 158.5 (C-12), 165.5 (C-15), 166.7 (C-10). Alkaloid 4. Oil. [a]:‘= +60.5 (EtOH; c 0.5). IR ~2: cm-‘: 3356 (OH), 1717 (ester), 1650 (C=C). Elemental analysis: calcd for C,sHz,O,N, C:64.09, H:8.01. Found C:64.30; 64.00, H: 8.10: 7.80. EIMS m/z (rel. int.): 55 (lOO), 82 (51), 83 (60), 94 (7), 95 (19). 97 (8), 122 (30), 138 (53). 222 (6), 237 (6), 337 (0.5). ‘HNMR: 1.92 (3H, d, 5=7.0 Hz, H-18), 1.93 (3H, d, J= 1.0 Hz, H-14) 2.02 (3H, d, J=7.0 Hz, H-13), 180-2.15 (4H, m, H-2 and H-6), 2.84 (2H, m, H-l and H-3,). 2.93 (lH, m, H-5,), 3.38 (lH, m, H-3,) 3.57 (lH, m, H-5,). 3.88 (lH, m, H-8), 4.28 (lH, 4, J =7.0 Hz,H-9u),4.35(2H,s, H-19),4.41 (lH,q,J=7.1 Hz,H-9d), 5.44 (lH, br s, H-7), 6.16 (lH, q, J=6.9 Hz, H-12), 6.97 (lH, q. J =7.5 Hz, H-17). ‘aCNMR: 14.3 (C-18), 15.9 (C-14), 20.8 (C-13), 28.7 (C-2), 34.8 (C-6), 40.0 (C-4), 53.5 (C-5), 54.6 (C-3), 56.6 (C-19), 63.2 (C-9), 68.9 (C-7), 74.7 (C-8), 126.6 (C-11). 131.8 (C-16) 140.7 (C-12), 140.8 (C-17), 166.4 (C-15). 166.7 (C-10). Acknowledgements This work was supported by the foundation of the Natural Science of China. We thank the Analytic Center, Lanzhou University, for their enthusiastic help and for elemental analysis.
REFERENCES
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