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Lignans, γ-lactones and propiophenones of Virola surinamensis
Pergamon
Phvtochemistry, VoI. 43, No. 5, pp. 1089-1092. 1996
PII: S0031-9422(96)00408-6
Copyright (~) 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0031-9422/96 $15.00 + 0.00
LIGNANS, y-LACTONES AND PROPIOPHENONES OF VIROLA SURINAMENSIS NORBERTO PEPORINELOPES, EMA ESTER DE ALMEIDABLUMENTHAL,*ALBERTOJOS~ CAVALHEIRO,MASSUOJORGE KATOt and MASSAYOSHIYOSH1DA Instituto de Quimica, Universidade de S~o Paulo, C.E 26077, 05599-970, Silo Paulo, Brazil; *Instituto Butantan, Secretaria de Estado de Satide, C.E 65, S~o Paulo, Brazil (Received in revised form 7 May 1996)
Key Word I n d e x - - V i r o l a surinamensis; Myristicaceae; lignans; 7-1actones; propiophenones.
Abstract--The leaves and seeds of Virola surinamensis contain 17 lignans: fragansins A2 and D2, galbacin, galbelgin, 5-methoxygalbelgin, grandisin, verrucosin, aristolignan, austrobailignan, calopeptin, veraguensin, 5methoxyveraguensin, nectandrin B, galbulin and galcatin; three propiophenone derivatives; two y-lactones: juruenolide C and juruenolide D. Three lignans, one y-lactone and one propiophenone are new natural products. Copyright © 1996 Elsevier Science Ltd
INTRODUCTION The occurrence of arylpropanoids, lignans and neolignans in leaves of the Amazonian tree Virola surinamensis (Myristicaceae) has been previously reported [1-3]. The neolignans virolin and surinamensin isolated from leaves showed activity against penetration of cercaria of Schistosoma mansoni [2]. More recently, investigation carried out on leaves from seedling and micropropagated plants revealed a composition based on the occurrence of juruenolide C [4]. Re-examination of apolar extracts from leaves and seeds for bioactive neolignans afforded two y-lactones, three propiophenone derivatives and 17 lignans. The isolation and structural determination of these compounds are the objectives of this paper.
RESULTS AND DISCUSSION
The chlorophyll-free dichloromethane fraction [5] from leaves of V. surinamensis, submitted to flash chromatography and subsequent fractionation by prep. TLC, yielded galbacin (lb) [1], galbelgin (lc) [6], le, lf, grandisin (lg) [7], verrucosin (2a) [8], veraguensin (2e) [1], 2f and 7 [9]. The methanol fraction of hexane extract from seeds, submitted to CC followed by prep. TLC or prep. HPLC, gave fragansins A2 (la) and D2 (ld) [10], aristolignan (2b) [11], austrobailignan (2c) [12], calopeptin (2d) [13], nectandrin B (3) [14], 4a [15], 4b, 4c [15], juruenolide C (5a) [4], 5b, galbulin (6a) [16] and galcatin (6b) [16], besides lb, lc, lf, 2a and 2e.
#Author to whom correspondence should be addressed.
The compounds l a - l d , lg, 2a-2e, 3, 4a, 4e, 5a, 6a-6b and 7, previously isolated, were identified by comparison to reported spectroscopic data. The 'H NMR spectra of le and I f showed absorptions of oxybenzylic protons H-7 and H-7' (6 4.61-+0.01, d, J = 9.1_+0.1 Hz), and methyl protons H-9 (6 1.06 d, J = 5.9 Hz) and H-9' (6 1.03 d, J = 6.1 Hz) related to a tetrahydrofuran moiety. These chemical shifts and the signal of optical rotations indicated that these lignans possess the same configurations as ( - ) galbelgin [17]. In the aromatic region of the ~H NMR spectrum of le, the singlet at t3 6.60 can be assigned to H-2 and H-6 of the 3,4,5-trimethoxyphenyl group while a multiplet at 6.84 t3 (3H) associated with signal at 5.9 (2H) can be assigned to the absorption of the 3,4-methylenedioxyphenyl protons. Therefore the structure (7S,8S,7'S,8'S) - 3,4,5 - trimethoxy - 3',4' methylenedioxy - 7,7' - epoxylignan can be depicted for compound le. Compound I f differs from le only in the pattern of one aromatic ring: in I f the veratryl group replaced by piperonyl group of le. Compound 2f presents the same constitution of lf, but has the same configuration of veraguensin 2e [1]. The differential NOE spectra of 2f showed enhancement of signals for H-7 and H-7' when the aromatics protons at 6 6.73 (H-2, H-6) and at 6 6.85 (H-2', H-3', H-5') were irradiated respectively. These observations indicated the trans configuration between the 3,4,5-trimethoxyphenyl group and the methyl group. Thus compounds I f and 2f are respectively (7S,8S,7'S,8'S) and (7S,8S,7'R,8'S)3,4,5,3 ',4' -pentamethoxy -7,7' -epoxylignan. Compound 4b showed a molecular ion at m / z 224 and a base peak at 195 in its mass spectrum, carbonyl absorption at 1681 cm ~ in its IR spectrum, and trimethoxyphenyl and propionyl groups in ~H NMR
1089
1090
N.P. LOPESet al. 9
9' . , d I'
RI"
k2
~2
~
~R4
fd 1
2
H
OCH20
H
R s OMe hOMe
c OMe
OMe
H
OMe
OMe
H
e OCH20
H
d OMe
OH
H
OMe
OM.e
OMe
OH OMe
OMe OMe OMe
OMe OMe OMe
OCH20 OMe OMe
OMe
OMe OMe
H H OMe
H H
OMe OMe
• OMe tOMe g OlVle
d OCH20 • OMe O/de f OMe
OMe
OMe
OlVIe OMe
R • OMe
R' OH
b OCH20
R~ H
R3 OMe
R" OH
R5 H
RI OH OH
OMe
R2 H H
R3 OMe OMe
R4 OH OMe
3
O ~tt
~
1!
~
........ 2
......O H
R t 2
4 R
,,, OMe b OMe © OM©
RI OMe OMe OH
5 R2
a n----5
H
bn---q
OMe H
spectrum. These data defined the structure as 3,4,5trimethoxypropiophenone for compound 4b. The 1H NMR spectra of 5b and juruenolide C [4] are closely comparable. The difference between these two butenolides consists of the length of the methylene chain, as shown from the mass spectrum giving molecular ions at m / z 362 vs m / z 334 in jurenolide C. The absence of surinamensin and virolin observed in many analyses carried out on leaves collected at Combtl Island, suggest that these compounds do not belong to the normal constitution of secondary metabolites of V. surinamensis, or have been detected in one particular individual growing under special circumstances. The
reasons for such differences should be further investigated. V. surinamensis contains tetrahydrofuran lignans with di- or tri-oxygenated aromatic rings, and in leaves it was observed that lignans with two dioxygenated ring predominated (66%) over the di/tri or tri/tri oxygenated pattern (34%).
EXPERIMENTAL General. Prep. TLC was carried out on Si gel PF-254 (Merck) and CC on Si gel 60H (0.005-0.045 mm)
Lignans, 7-1actones and propiophenones of Virola surinamensis
1091
( OH
'7
6 R R1 • O1~ O/d_~ b O(2I-I~O
(Merck). Mp without corrections were obtained on electrothermal equipment. Optical rotations were measured on Polamat A-Carl Zeiss. The ~H NMR (200 MHz) and ~3C NMR (50 MHz) spectra were recorded on Bruker-AC 200 in CDC13 with TMS as int. standard. El-MS was obtained at 70 eV on HP 5988-A. Plant material. Leaves and seeds of V. surinamensis (Rol.) Warb. were collected in July 1990 at Combtl Island, near Bel~m, Pardi State, Brazil. Isolation o f constituents. Air-dried and powdered leaves (100 g) were extracted with CH2C12 at room temp. The extract (7.15 g) suspended in 200 ml of MeOH-HzO (7:3) soln was filtered on Celite. The filtered soln was extracted with hexane (3 × 50 ml) followed by CH2C12 (3 × 75 ml). The CH2C12 extract (3.3 g) was submitted to flash CC (165 g) eluted with hexane-EtOAc at increasing polarities and gave 8 pooled frs. The following frs submitted to prep. TLC (silica gel) yielded the indicated compounds: Fr. B, galbacin l b (35 mg), Fr. C, l e (4 mg), Fr. D, 2f (18 mg) and 7 (15 mg), Fr. E, veraguensin 2e (80 mg) and grandisin l g (30 mg), Fr. F, verrucosin 2b (25 mg) and galbelgin l c (70 mg), and Fr. G, I f (32 mg). Seeds (teguments and kernels) (183 g) were dried, milled and extracted with hexane in a Soxhlet apparatus. The concentrated extract (91.2 g) was suspended in MeOH and kept overnight at 0 °. The lipid material was removed by filtration and the filtrate concd in vacuo to yield 13.2 g. This extract was submitted to partition between hexane/MeOH-H20 (10%). The MeOH layer was concd under vacuum to yield 1.8 g which was submitted to flash CC (silica-gel, hexaneEtOAc 8:2) furnishing frs I (663 mg), J (418 mg) and K (348 mg). Fr. I submitted to prep. TLC (silica-gel, hexane-EtOAc) gave galcatin 6b (1.5 mg) and galbacin l b (31.5 mg). Fr. J was submitted to prep. TLC (silica gel, hexane-EtOAc), followed by prep. HPLC (RP-8 column, 10 /xm, 250 × 4.6 mm column, MeOH-H20 57:43), Si-60 column (hexane-CH:C12-HOAc
50.0:49.5:0.5) and finally recrystallization in MeOH to afford galbulin (6a, 71 mg), calopeptin (2d, 5 mg), austrobailignan (2e, 3 mg), 4a (15 mb), 4b (3 mg) and 4c (8 mg). Fr. K was submitted to prep. TLC (silica gel, hexane-EtOAc) and recrystallization in Me2COhexane to yield 2e (42.5 mg), le (7.5 mg) and If (12 mg). Part of Fr. J (20 mg) was submitted to HPLC (RP-8, 10 /~m, 250 × 4.6 mm column, MeOH-HzO 55:45 to 85:15 in 20 min) to afford l a and 2a (0.8 mg), l d and 2b (3.2 mg), I f (0.5 mg), 3 (0.7 mg), 5a (3.5 mg) and 5b (0.3 mg). (7S,8S,7'S,8'S) - 3,4,5 Trimethoxy 3',4' methylenedioxy - 7,7' - epoxylignan (le). Yellow oil. [or]D-10.0 ° (c 0.02; CHC13). IR //max cm : 2945, 2918, 2842, 1590, 1508, 1465, 1248, 1240, 1125, 1040. 1H NMR (200 MHz, CDC13): 6 1.03 (3H, d, J = 5 . 7 Hz, H-9), 1.05 (3H, d, J=4.6, H-9'), 1.78 (2H, m, H-8, H-8'), 3.87 (6H, s, OMe), 3.82 (3H, s, OMe), 4.60 (2H, br d, J=9.0, H-7, H-7'), 5.90 (2H, s, OCH20), 6.60 (2H, s, H-2, H-6), 6.84 (3H, m, H-2', H-5', H-6'). ~3C NMR (50 MHz, CDCI3): 8 13.7 (C-9), 14.0 (C-9'), 50.9 (C-8), 51.2 (C-8'), 56.1 (OMe), 60.3 (OMe), 88.3 (C-7), 88.4 (C-7'), 100.9 (OCH20), 103.0 (C-2, C-6), 106.5 (C-2'), 107.9 (C-5'), 119.4 (C-6'), 136.4 (C-I'), 137.9 (C-I, C-4), 153.2 (C-3, C-5). MS m / z (rel. int): 386 [M] + (3), 236 (26), 224 (10), 208 (100), 196 (6), 190 (56), 178 (11), 176 (6), 162 (16), 150 (14). (7S,8S,7'S,8'S) - 3,4,5,3',4' - Pentarnethoxy - 7,7' epoxylignan (If). Oil. [a] D - 12.6° (c 0.15; CHCI3). IR Vmax cm : 2958, 2837, 1592, 1514, 1462, 1266, 1236, 1127, 1028. ~H NMR (200 MHz, CDCI3): 6 1.03 (3H, d, J=6.2, H-9), 1.06 (3H, d, J=5.9, H-9'), 1.77 (2H, m, H-8, H-8'), 3.81, 3.85, 3.86, 3.89 and 3.92 (s, 5 OMe), 4.62 (2H, d, J=9.1, H-7, H-7'), 6.60 (2H, s, H-2, H-6), 6.82 (IH, d, J=8.1, H-5'), 6.91 (1H, dd, J = l . 6 , 8.1, H-6'), 6.93 (1H, d, J = l . 6 , H-2'). 13C NMR (50 MHz, CDCI3): 8 13.8 (C-9), 14.0 (C-9'), 50.9 (C-8), 51.0 (C-8'), 55.9, 56.1, 60.8 (50Me), 88.3 (C-7), 88.4 (C-7'), 103.0 (C-2, C-6), 109.1 (C-5'), film
film
-- 1
-- 1
1092
N. E LopEset al.
110.8 (C-2'), 118.6 (C-6'), 134.8 (C-I'), 137.3 (C-4), 138.1 (C-I), 148.5 (C-4'), 149.1 (C-3'), 153.2 (C-3, C-5). MS m / z (rel. int.): 402 [M] ÷ (23), 236 (34), 224 (12), 221 (32), 208 (100), 206 (50), 196 (5), 195 (12), 194 (35), 191 (45), 178 (22), 166 (6), 165 (18). (7S,8S,7'R,8'S) - 3' ,4' Dimethoxy 3,4 methylenedioxy - 7,7' - epoxylignan (2d). Oil. 13C NMR (50 MHz, CDC13): 8 14.9 and 15.1 (C-9, C-9'), 45.9 (C-8), 48.3 (C-8'), 55.8 (20Me), 83.0 (C-7'), 87.4 (C-7), 101.0 (OCH20), 106.9 (C-2), 108.1 (C-5), 110.3 (C-2'), 110.7 (C-5'), 119.2 (C-6'), 120.1 (C-6), 133.7 (C-I'), 134.8 (C-I), 147.1 (C-4), 147.8 (C-3), 148.0 (C-4'), 148.6 (C-3'). (7S,8S,7'R,8'S) - 3,4,5,3',4' - Pentamethoxy-7,7' epoxylignan (2f). Yellow oil. [C~]D+16.0° (C 0.15; film CHCI3). IR /Jmax cm 1 2944, 2920, 1590, 1505, 1461, 1262, 1235, 1129.1H NMR (200 MHz, CDC13): t~ 0.65 (3H, d, J=6.9, H-9'), 1.09 (3H, d, J=6.5, H-9), 1.72 (IH, m, H-8), 2.23 (1H, m, H-8'), 3.84 (6H, s, OMe), 3.87 (3H, s, OMe), 3.88 (6H, s, OMe), 4.40 (IH, d, J=9.1, H-7), 5.13 (1H, d, J=8.6, H-7'), 6.73 (2H, s, H-2, H-6), 6.85(3H, m, H-2', H-5', H-6'). 13C NMR (50 MHz, CDC13): t~ 14.9 (C-9'), 15.2 (C-9), 45.9 (C-8'), 48.0 (C-8), 55.7 (OMe), 55.8 (OMe), 56.0 (OMe), 60.8 (OMe), 83.0 (C-7'), 88.3 (C-7), 103.3 (C-2, C-6), 110.3 (C-2'), 110.6 (C-5'), 119.2 (C-6'), 133.6 (C-I), 136.4 (C-I'), 137.4 (C-4), 148.5 (C-3'), 148.0 (C-3'), 153.2 (C-3, C-5). MS m / z (rel. int.): 402 [M] ÷ (31), 236 (98), 224 (13), 222 (12), 208 (45), 206 (100), 196 (15), 194 (20), 192 (11), 178 (20), 166 (21). 3,4,5-Trimethoxypropiophenone (4b). Yellow oil. IR film -- I Vmax cm : 1681, 1587, 1506, 1462, 1355, 1317, 1163, 1128, 865. ~H NMR (200 mHz, CDC13): t~ 1.21 (3H, t, J=7.2, H-9), 2.95 (2H, q, J=7.2, H-8), 3.90 (9H, s, OMe), 7.21 (2H, s, H-2, H-6). 13C NMR (50 MHz, CDCl3): t~ 8.4 (C-9), 31.6 (C-8), 56.3 (20Me), 60.9 (OMe), 105.5 (C-2, C-6), 153.0 (C-3, C-5), 199.6 (C-7). MS m / z (rel. int.): 224 [M] + (35), 195 (100), 167 (7), 152 (9), 137 (7), 122 (6). (2S*,3R*,4S*) - Hydroxy - methyl - 2 - [(9"piperonyl) - n - nonyl] - butanolide (Sb). IH NMR (200 MHz, CDC13): t5 2.59 (IH, dt, J=5.5, 9.0, H-2), 4.18 (IH, br d, J--5.5, H-3), 4.51 (1H, br q, J=6.5, H-4), 1.34 (3H, d, J=6.5, Me-4), 1.68 (2H, m, H-I'), 1.4 (14H, m, H-2'), H-3', H-4', H-5', H-6', H-7', H-8'),
2.52 (2H, t, J=7.8, H-9'), 6.66 (1H, d, J = 1.3, H-2"), 6.72 (1H, d, J=7.8, H-5"), 6.61 (1H, dd, J = 1.3 and 7.8, H-6"), 5.90 (2H, s, OCH20). MS m / z (rel. int.): 362 [M] ÷ (28), 290 (2), 246 (5), 212 (2), 207 (2), 149 (3), 148 (6), 136 (29), 135 (100), 105 (5), 99 (2), 91 (6), 77 (12), 57 (15). REFERENCES
1. Barata, L. E. S. and Baker, P. M. (1973) Cienc. Cult. (Suppl.) 25, 169. 2. Barata, L. E. S., Baker, E M., Gottlieb, O. R. and Rtiveda, E. A. (1978) Phytochemistry 17, 783. 3. Barata, L. E. S. and Panlo, M. Q. (1982) Cienc. Cult. (Suppl.) 33, 445. 4. Lopes, N. P., Franqa, S. C., Pereira, A. M. S., Maia, G. S., Kato, M. J., Cavalheiro, A. J., Gottlieb, O. R. and Yoshida, M. (1994) Phytochemistry 35, 1469. 5. Fernandes, A. M. A. P., Barata L. E. S. and Ferri, P. H. (1993) Phytochemistry 32, 1567. 6. Sumathykutty, M. A. and Rao, J. M. (1991) Phytochemistry 30, 2075. 7. Barbosa-Filho, J. M., Silva, M. S., Yoshida, M. and Gottlieb, O. R. (1989) Phytochemistry 28, 2209. 8. Dias, A. F., Giesbrecht, A. M. and Gottlieb, O. R. (1982) Phytochemistry 21, 1137. 9. Pinto, M. M. M., Kijjoa, A. Mondranondra, I. Guti6rrez, A. B. and Herz, W. (1990) Phytochemistry 29, 1985. 10. Hattori, M., Hada, S., Kawata, Y., Tezuka, Y., Kikuchi, T. and Namba, T. (1987) Chem. Pharm. Bull. 35, 3315. 11. Urztla, A., Freyer, A. J. and Shama, M. (1987) Phytochemistry 26, 1509. 12. Hada, S., Hattori, M., Tezuka, Y., Kikuchi, T. and Namba, T. (1988) Phytochemistry 27, 563. 13. Doskotch, R. W. and Flom, M. S. (1972) Tetrahedron 28, 4711. 14. Le Quesne, P. W., Larrahondo, J. E. and Raffauf, R. R. (1980) J. Nat. Prod. 43, 353. 15. Zdero, C., Jakupovic, J. and Bohlmann, F. (1990) Phytochemistry 29, 1231. 16. Hughes, G. K. and Ritchie, E. (1954) Aust. J. Chem. 7, 104. 17. Birch, A. J., Milligan, B., Smith, E. and Speak, E N. (1958) J. Chem. Soc., 4471.
Phvtochemistry, VoI. 43, No. 5, pp. 1089-1092. 1996
PII: S0031-9422(96)00408-6
Copyright (~) 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0031-9422/96 $15.00 + 0.00
LIGNANS, y-LACTONES AND PROPIOPHENONES OF VIROLA SURINAMENSIS NORBERTO PEPORINELOPES, EMA ESTER DE ALMEIDABLUMENTHAL,*ALBERTOJOS~ CAVALHEIRO,MASSUOJORGE KATOt and MASSAYOSHIYOSH1DA Instituto de Quimica, Universidade de S~o Paulo, C.E 26077, 05599-970, Silo Paulo, Brazil; *Instituto Butantan, Secretaria de Estado de Satide, C.E 65, S~o Paulo, Brazil (Received in revised form 7 May 1996)
Key Word I n d e x - - V i r o l a surinamensis; Myristicaceae; lignans; 7-1actones; propiophenones.
Abstract--The leaves and seeds of Virola surinamensis contain 17 lignans: fragansins A2 and D2, galbacin, galbelgin, 5-methoxygalbelgin, grandisin, verrucosin, aristolignan, austrobailignan, calopeptin, veraguensin, 5methoxyveraguensin, nectandrin B, galbulin and galcatin; three propiophenone derivatives; two y-lactones: juruenolide C and juruenolide D. Three lignans, one y-lactone and one propiophenone are new natural products. Copyright © 1996 Elsevier Science Ltd
INTRODUCTION The occurrence of arylpropanoids, lignans and neolignans in leaves of the Amazonian tree Virola surinamensis (Myristicaceae) has been previously reported [1-3]. The neolignans virolin and surinamensin isolated from leaves showed activity against penetration of cercaria of Schistosoma mansoni [2]. More recently, investigation carried out on leaves from seedling and micropropagated plants revealed a composition based on the occurrence of juruenolide C [4]. Re-examination of apolar extracts from leaves and seeds for bioactive neolignans afforded two y-lactones, three propiophenone derivatives and 17 lignans. The isolation and structural determination of these compounds are the objectives of this paper.
RESULTS AND DISCUSSION
The chlorophyll-free dichloromethane fraction [5] from leaves of V. surinamensis, submitted to flash chromatography and subsequent fractionation by prep. TLC, yielded galbacin (lb) [1], galbelgin (lc) [6], le, lf, grandisin (lg) [7], verrucosin (2a) [8], veraguensin (2e) [1], 2f and 7 [9]. The methanol fraction of hexane extract from seeds, submitted to CC followed by prep. TLC or prep. HPLC, gave fragansins A2 (la) and D2 (ld) [10], aristolignan (2b) [11], austrobailignan (2c) [12], calopeptin (2d) [13], nectandrin B (3) [14], 4a [15], 4b, 4c [15], juruenolide C (5a) [4], 5b, galbulin (6a) [16] and galcatin (6b) [16], besides lb, lc, lf, 2a and 2e.
#Author to whom correspondence should be addressed.
The compounds l a - l d , lg, 2a-2e, 3, 4a, 4e, 5a, 6a-6b and 7, previously isolated, were identified by comparison to reported spectroscopic data. The 'H NMR spectra of le and I f showed absorptions of oxybenzylic protons H-7 and H-7' (6 4.61-+0.01, d, J = 9.1_+0.1 Hz), and methyl protons H-9 (6 1.06 d, J = 5.9 Hz) and H-9' (6 1.03 d, J = 6.1 Hz) related to a tetrahydrofuran moiety. These chemical shifts and the signal of optical rotations indicated that these lignans possess the same configurations as ( - ) galbelgin [17]. In the aromatic region of the ~H NMR spectrum of le, the singlet at t3 6.60 can be assigned to H-2 and H-6 of the 3,4,5-trimethoxyphenyl group while a multiplet at 6.84 t3 (3H) associated with signal at 5.9 (2H) can be assigned to the absorption of the 3,4-methylenedioxyphenyl protons. Therefore the structure (7S,8S,7'S,8'S) - 3,4,5 - trimethoxy - 3',4' methylenedioxy - 7,7' - epoxylignan can be depicted for compound le. Compound I f differs from le only in the pattern of one aromatic ring: in I f the veratryl group replaced by piperonyl group of le. Compound 2f presents the same constitution of lf, but has the same configuration of veraguensin 2e [1]. The differential NOE spectra of 2f showed enhancement of signals for H-7 and H-7' when the aromatics protons at 6 6.73 (H-2, H-6) and at 6 6.85 (H-2', H-3', H-5') were irradiated respectively. These observations indicated the trans configuration between the 3,4,5-trimethoxyphenyl group and the methyl group. Thus compounds I f and 2f are respectively (7S,8S,7'S,8'S) and (7S,8S,7'R,8'S)3,4,5,3 ',4' -pentamethoxy -7,7' -epoxylignan. Compound 4b showed a molecular ion at m / z 224 and a base peak at 195 in its mass spectrum, carbonyl absorption at 1681 cm ~ in its IR spectrum, and trimethoxyphenyl and propionyl groups in ~H NMR
1089
1090
N.P. LOPESet al. 9
9' . , d I'
RI"
k2
~2
~
~R4
fd 1
2
H
OCH20
H
R s OMe hOMe
c OMe
OMe
H
OMe
OMe
H
e OCH20
H
d OMe
OH
H
OMe
OM.e
OMe
OH OMe
OMe OMe OMe
OMe OMe OMe
OCH20 OMe OMe
OMe
OMe OMe
H H OMe
H H
OMe OMe
• OMe tOMe g OlVle
d OCH20 • OMe O/de f OMe
OMe
OMe
OlVIe OMe
R • OMe
R' OH
b OCH20
R~ H
R3 OMe
R" OH
R5 H
RI OH OH
OMe
R2 H H
R3 OMe OMe
R4 OH OMe
3
O ~tt
~
1!
~
........ 2
......O H
R t 2
4 R
,,, OMe b OMe © OM©
RI OMe OMe OH
5 R2
a n----5
H
bn---q
OMe H
spectrum. These data defined the structure as 3,4,5trimethoxypropiophenone for compound 4b. The 1H NMR spectra of 5b and juruenolide C [4] are closely comparable. The difference between these two butenolides consists of the length of the methylene chain, as shown from the mass spectrum giving molecular ions at m / z 362 vs m / z 334 in jurenolide C. The absence of surinamensin and virolin observed in many analyses carried out on leaves collected at Combtl Island, suggest that these compounds do not belong to the normal constitution of secondary metabolites of V. surinamensis, or have been detected in one particular individual growing under special circumstances. The
reasons for such differences should be further investigated. V. surinamensis contains tetrahydrofuran lignans with di- or tri-oxygenated aromatic rings, and in leaves it was observed that lignans with two dioxygenated ring predominated (66%) over the di/tri or tri/tri oxygenated pattern (34%).
EXPERIMENTAL General. Prep. TLC was carried out on Si gel PF-254 (Merck) and CC on Si gel 60H (0.005-0.045 mm)
Lignans, 7-1actones and propiophenones of Virola surinamensis
1091
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6 R R1 • O1~ O/d_~ b O(2I-I~O
(Merck). Mp without corrections were obtained on electrothermal equipment. Optical rotations were measured on Polamat A-Carl Zeiss. The ~H NMR (200 MHz) and ~3C NMR (50 MHz) spectra were recorded on Bruker-AC 200 in CDC13 with TMS as int. standard. El-MS was obtained at 70 eV on HP 5988-A. Plant material. Leaves and seeds of V. surinamensis (Rol.) Warb. were collected in July 1990 at Combtl Island, near Bel~m, Pardi State, Brazil. Isolation o f constituents. Air-dried and powdered leaves (100 g) were extracted with CH2C12 at room temp. The extract (7.15 g) suspended in 200 ml of MeOH-HzO (7:3) soln was filtered on Celite. The filtered soln was extracted with hexane (3 × 50 ml) followed by CH2C12 (3 × 75 ml). The CH2C12 extract (3.3 g) was submitted to flash CC (165 g) eluted with hexane-EtOAc at increasing polarities and gave 8 pooled frs. The following frs submitted to prep. TLC (silica gel) yielded the indicated compounds: Fr. B, galbacin l b (35 mg), Fr. C, l e (4 mg), Fr. D, 2f (18 mg) and 7 (15 mg), Fr. E, veraguensin 2e (80 mg) and grandisin l g (30 mg), Fr. F, verrucosin 2b (25 mg) and galbelgin l c (70 mg), and Fr. G, I f (32 mg). Seeds (teguments and kernels) (183 g) were dried, milled and extracted with hexane in a Soxhlet apparatus. The concentrated extract (91.2 g) was suspended in MeOH and kept overnight at 0 °. The lipid material was removed by filtration and the filtrate concd in vacuo to yield 13.2 g. This extract was submitted to partition between hexane/MeOH-H20 (10%). The MeOH layer was concd under vacuum to yield 1.8 g which was submitted to flash CC (silica-gel, hexaneEtOAc 8:2) furnishing frs I (663 mg), J (418 mg) and K (348 mg). Fr. I submitted to prep. TLC (silica-gel, hexane-EtOAc) gave galcatin 6b (1.5 mg) and galbacin l b (31.5 mg). Fr. J was submitted to prep. TLC (silica gel, hexane-EtOAc), followed by prep. HPLC (RP-8 column, 10 /xm, 250 × 4.6 mm column, MeOH-H20 57:43), Si-60 column (hexane-CH:C12-HOAc
50.0:49.5:0.5) and finally recrystallization in MeOH to afford galbulin (6a, 71 mg), calopeptin (2d, 5 mg), austrobailignan (2e, 3 mg), 4a (15 mb), 4b (3 mg) and 4c (8 mg). Fr. K was submitted to prep. TLC (silica gel, hexane-EtOAc) and recrystallization in Me2COhexane to yield 2e (42.5 mg), le (7.5 mg) and If (12 mg). Part of Fr. J (20 mg) was submitted to HPLC (RP-8, 10 /~m, 250 × 4.6 mm column, MeOH-HzO 55:45 to 85:15 in 20 min) to afford l a and 2a (0.8 mg), l d and 2b (3.2 mg), I f (0.5 mg), 3 (0.7 mg), 5a (3.5 mg) and 5b (0.3 mg). (7S,8S,7'S,8'S) - 3,4,5 Trimethoxy 3',4' methylenedioxy - 7,7' - epoxylignan (le). Yellow oil. [or]D-10.0 ° (c 0.02; CHC13). IR //max cm : 2945, 2918, 2842, 1590, 1508, 1465, 1248, 1240, 1125, 1040. 1H NMR (200 MHz, CDC13): 6 1.03 (3H, d, J = 5 . 7 Hz, H-9), 1.05 (3H, d, J=4.6, H-9'), 1.78 (2H, m, H-8, H-8'), 3.87 (6H, s, OMe), 3.82 (3H, s, OMe), 4.60 (2H, br d, J=9.0, H-7, H-7'), 5.90 (2H, s, OCH20), 6.60 (2H, s, H-2, H-6), 6.84 (3H, m, H-2', H-5', H-6'). ~3C NMR (50 MHz, CDCI3): 8 13.7 (C-9), 14.0 (C-9'), 50.9 (C-8), 51.2 (C-8'), 56.1 (OMe), 60.3 (OMe), 88.3 (C-7), 88.4 (C-7'), 100.9 (OCH20), 103.0 (C-2, C-6), 106.5 (C-2'), 107.9 (C-5'), 119.4 (C-6'), 136.4 (C-I'), 137.9 (C-I, C-4), 153.2 (C-3, C-5). MS m / z (rel. int): 386 [M] + (3), 236 (26), 224 (10), 208 (100), 196 (6), 190 (56), 178 (11), 176 (6), 162 (16), 150 (14). (7S,8S,7'S,8'S) - 3,4,5,3',4' - Pentarnethoxy - 7,7' epoxylignan (If). Oil. [a] D - 12.6° (c 0.15; CHCI3). IR Vmax cm : 2958, 2837, 1592, 1514, 1462, 1266, 1236, 1127, 1028. ~H NMR (200 MHz, CDCI3): 6 1.03 (3H, d, J=6.2, H-9), 1.06 (3H, d, J=5.9, H-9'), 1.77 (2H, m, H-8, H-8'), 3.81, 3.85, 3.86, 3.89 and 3.92 (s, 5 OMe), 4.62 (2H, d, J=9.1, H-7, H-7'), 6.60 (2H, s, H-2, H-6), 6.82 (IH, d, J=8.1, H-5'), 6.91 (1H, dd, J = l . 6 , 8.1, H-6'), 6.93 (1H, d, J = l . 6 , H-2'). 13C NMR (50 MHz, CDCI3): 8 13.8 (C-9), 14.0 (C-9'), 50.9 (C-8), 51.0 (C-8'), 55.9, 56.1, 60.8 (50Me), 88.3 (C-7), 88.4 (C-7'), 103.0 (C-2, C-6), 109.1 (C-5'), film
film
-- 1
-- 1
1092
N. E LopEset al.
110.8 (C-2'), 118.6 (C-6'), 134.8 (C-I'), 137.3 (C-4), 138.1 (C-I), 148.5 (C-4'), 149.1 (C-3'), 153.2 (C-3, C-5). MS m / z (rel. int.): 402 [M] ÷ (23), 236 (34), 224 (12), 221 (32), 208 (100), 206 (50), 196 (5), 195 (12), 194 (35), 191 (45), 178 (22), 166 (6), 165 (18). (7S,8S,7'R,8'S) - 3' ,4' Dimethoxy 3,4 methylenedioxy - 7,7' - epoxylignan (2d). Oil. 13C NMR (50 MHz, CDC13): 8 14.9 and 15.1 (C-9, C-9'), 45.9 (C-8), 48.3 (C-8'), 55.8 (20Me), 83.0 (C-7'), 87.4 (C-7), 101.0 (OCH20), 106.9 (C-2), 108.1 (C-5), 110.3 (C-2'), 110.7 (C-5'), 119.2 (C-6'), 120.1 (C-6), 133.7 (C-I'), 134.8 (C-I), 147.1 (C-4), 147.8 (C-3), 148.0 (C-4'), 148.6 (C-3'). (7S,8S,7'R,8'S) - 3,4,5,3',4' - Pentamethoxy-7,7' epoxylignan (2f). Yellow oil. [C~]D+16.0° (C 0.15; film CHCI3). IR /Jmax cm 1 2944, 2920, 1590, 1505, 1461, 1262, 1235, 1129.1H NMR (200 MHz, CDC13): t~ 0.65 (3H, d, J=6.9, H-9'), 1.09 (3H, d, J=6.5, H-9), 1.72 (IH, m, H-8), 2.23 (1H, m, H-8'), 3.84 (6H, s, OMe), 3.87 (3H, s, OMe), 3.88 (6H, s, OMe), 4.40 (IH, d, J=9.1, H-7), 5.13 (1H, d, J=8.6, H-7'), 6.73 (2H, s, H-2, H-6), 6.85(3H, m, H-2', H-5', H-6'). 13C NMR (50 MHz, CDC13): t~ 14.9 (C-9'), 15.2 (C-9), 45.9 (C-8'), 48.0 (C-8), 55.7 (OMe), 55.8 (OMe), 56.0 (OMe), 60.8 (OMe), 83.0 (C-7'), 88.3 (C-7), 103.3 (C-2, C-6), 110.3 (C-2'), 110.6 (C-5'), 119.2 (C-6'), 133.6 (C-I), 136.4 (C-I'), 137.4 (C-4), 148.5 (C-3'), 148.0 (C-3'), 153.2 (C-3, C-5). MS m / z (rel. int.): 402 [M] ÷ (31), 236 (98), 224 (13), 222 (12), 208 (45), 206 (100), 196 (15), 194 (20), 192 (11), 178 (20), 166 (21). 3,4,5-Trimethoxypropiophenone (4b). Yellow oil. IR film -- I Vmax cm : 1681, 1587, 1506, 1462, 1355, 1317, 1163, 1128, 865. ~H NMR (200 mHz, CDC13): t~ 1.21 (3H, t, J=7.2, H-9), 2.95 (2H, q, J=7.2, H-8), 3.90 (9H, s, OMe), 7.21 (2H, s, H-2, H-6). 13C NMR (50 MHz, CDCl3): t~ 8.4 (C-9), 31.6 (C-8), 56.3 (20Me), 60.9 (OMe), 105.5 (C-2, C-6), 153.0 (C-3, C-5), 199.6 (C-7). MS m / z (rel. int.): 224 [M] + (35), 195 (100), 167 (7), 152 (9), 137 (7), 122 (6). (2S*,3R*,4S*) - Hydroxy - methyl - 2 - [(9"piperonyl) - n - nonyl] - butanolide (Sb). IH NMR (200 MHz, CDC13): t5 2.59 (IH, dt, J=5.5, 9.0, H-2), 4.18 (IH, br d, J--5.5, H-3), 4.51 (1H, br q, J=6.5, H-4), 1.34 (3H, d, J=6.5, Me-4), 1.68 (2H, m, H-I'), 1.4 (14H, m, H-2'), H-3', H-4', H-5', H-6', H-7', H-8'),
2.52 (2H, t, J=7.8, H-9'), 6.66 (1H, d, J = 1.3, H-2"), 6.72 (1H, d, J=7.8, H-5"), 6.61 (1H, dd, J = 1.3 and 7.8, H-6"), 5.90 (2H, s, OCH20). MS m / z (rel. int.): 362 [M] ÷ (28), 290 (2), 246 (5), 212 (2), 207 (2), 149 (3), 148 (6), 136 (29), 135 (100), 105 (5), 99 (2), 91 (6), 77 (12), 57 (15). REFERENCES
1. Barata, L. E. S. and Baker, P. M. (1973) Cienc. Cult. (Suppl.) 25, 169. 2. Barata, L. E. S., Baker, E M., Gottlieb, O. R. and Rtiveda, E. A. (1978) Phytochemistry 17, 783. 3. Barata, L. E. S. and Panlo, M. Q. (1982) Cienc. Cult. (Suppl.) 33, 445. 4. Lopes, N. P., Franqa, S. C., Pereira, A. M. S., Maia, G. S., Kato, M. J., Cavalheiro, A. J., Gottlieb, O. R. and Yoshida, M. (1994) Phytochemistry 35, 1469. 5. Fernandes, A. M. A. P., Barata L. E. S. and Ferri, P. H. (1993) Phytochemistry 32, 1567. 6. Sumathykutty, M. A. and Rao, J. M. (1991) Phytochemistry 30, 2075. 7. Barbosa-Filho, J. M., Silva, M. S., Yoshida, M. and Gottlieb, O. R. (1989) Phytochemistry 28, 2209. 8. Dias, A. F., Giesbrecht, A. M. and Gottlieb, O. R. (1982) Phytochemistry 21, 1137. 9. Pinto, M. M. M., Kijjoa, A. Mondranondra, I. Guti6rrez, A. B. and Herz, W. (1990) Phytochemistry 29, 1985. 10. Hattori, M., Hada, S., Kawata, Y., Tezuka, Y., Kikuchi, T. and Namba, T. (1987) Chem. Pharm. Bull. 35, 3315. 11. Urztla, A., Freyer, A. J. and Shama, M. (1987) Phytochemistry 26, 1509. 12. Hada, S., Hattori, M., Tezuka, Y., Kikuchi, T. and Namba, T. (1988) Phytochemistry 27, 563. 13. Doskotch, R. W. and Flom, M. S. (1972) Tetrahedron 28, 4711. 14. Le Quesne, P. W., Larrahondo, J. E. and Raffauf, R. R. (1980) J. Nat. Prod. 43, 353. 15. Zdero, C., Jakupovic, J. and Bohlmann, F. (1990) Phytochemistry 29, 1231. 16. Hughes, G. K. and Ritchie, E. (1954) Aust. J. Chem. 7, 104. 17. Birch, A. J., Milligan, B., Smith, E. and Speak, E N. (1958) J. Chem. Soc., 4471.