Siddiqui, Zeba N

Zaman, Asif

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Indian Journal of ChemistryVol. 37B, October 1998, pp. 1081 - 1082Chemical constituents ofDesmodium sequaxZeba N Siddiqui" & AsifZamanDepartment of Chemistry, Aligarh Muslim University,Aligarh 202 002, IndiaReceived 16 April 1996; accepted (revised)14 August 1997The chloroform extract of the air dried stem-wood ofDesmodium seq~ax on column chromatographyyields sixcompounds which have been characterized as karanjin 1,lanceolatin-B 2, pongapin 3, 5'-methoxypongapin 5,kanujin 6 and glabra-II 4.Desmodium sequax (leguminaceae) has been foundto be medicinally important I. Much work onDesmodium species has been reported by Ghosalet al.' They isolated a number of indole alkaloidsfrom it. Flavonoids and pterocarpanes have alsobeen reported':". In the present investigation effortswere directed towards separation of a number ofphenolic compounds which appeared on TLCplates of the extract as fluorescent spots. The crudeextract was subjected to coloumn chromatographyand karanjin, lanceolatin-B, pongapin, 5'-methoxypongapin, kanujin and glabra-II wereisolated and characterized.Experimental SectionExtraction and isolation of the compounds.The air dried stem-wood (12 kg) was defatted andextracted with chloroform. The chloroform extractafter removal of the solvent under reduced pressuregave a brownish black gummy residue (40 g). Thecrude material was subjected to the coloumnchromatography using chloroform-petroleum ethermixture as eluent gave the following compounds.Karanjin 1. It was obtained using chloroformpetroleum-ether (50:50, v/v) as eluent, andcrystallized from benzene-petroleum ether to yieldtransparent white -rectangular crystals' (500 mg),mp 160°C; IR (Nujol): 1635, 1625, 1605, 1570,1525, 1410, 1340, 1285, 1225, 1160, 1040, 950,760 ern"; MS: mlz 292 (~., 70%), 291 (100),273NoteRRc (0-(VI) R _ Oe"3 , R,-R2-0-o(1) II-Oe"3; R,.1I2 -R3-"(2) R - R,_RZ-R3 -" 0-(3) R -oe"3; R,-R2 - <0-(0-(4) R _H; R,-R.2- , Rl = Oe"l0-0-(5) R.oe"3, 11,- II"z = ( , "l =OCH30-(10), 263 (12), 176 (5), 160 (52), 145 (17), 132(20), 105 (16), 89 (15), 77 (30); IH NMR (CDCh):83.9 (3H, s, O-CH3, 3). 7.14 (IH, d, J=2 Hz, -0-CH=CH-), 7.75 (1H, d, J=2 Hz, -O-CH=CH-),7.4-8.1 (6H, m, Ar-H), 8.2 (1H, d, J=8.5 Hz, H-5).Lanceolatin-B 2. Elution of the column withchloroform petroleum ether (50:50,· v/v) gave afraction which on evaporation yielded an orangeyellow mass (4.0 g). The residue was furtherchromatographed over silica gel using benzene-ethyl acetate (98:2, v/v) as eluent. Appropriatefractions were combined and evaporated to give asolid which on crystallization from benzeneyielded cream colored needles" (75 mg), mp 138-40°C; IR (KBr): 1655, 1620, 1585, 1540, 1462,1420, 1375, 1270, 1152, 1080,862 em"; MS: mlz262 (M+·, 100%), 234 (100), 205 (14), 176 (24),161 (100), 160 (100),132 (100),117 (80),105(25), 104 (86), 102 (49), 77 (46); IHNMR(CDCh): 86.89 (1H, s, H-3), 7.22 (1H, d, J=1.84Hz, -OCH=CH-), 7.78 (IH, d, J=1.83 Hz,-OCH=CH-), 7.55-7.59 (4H, m, Ar-H), 7.95-7.99(2H, m, Ar-H), 8.17 (1H, d,J=9.16 Hz, H-5).Pongapin 3. It was obtained from a mixture ofchloroform-petroleum ether (50:50, v/v), andcrystallized from benzene-petroleum ether to yieldoff-white granules" (100 mg), mp 192-200°C; IR(KBr): 1640, 1625, 1600, 1570, 1500, 1450, 1415,1375, 1330, 1290, 1260, 1215, 1045, 760 em";MS: mlz 336 (M+-, 84%),335 (100),321 (12),3181082 INDIAN J CHEM, SEC.B,OCTOBER 1998(14), 307 (21), 293 (27), 161 (25), 160 (44), 146(48), 77 (32); IH NMR (CDCh): 03.90 (3H, S,OCH3, 3), 6.1 (2H, s, -O-CH2-O-), 7.20 (1H, d,J=2 Hz, -OCH-CH-), 7.75 (IH, s, J=2 Hz,-OCH=CH-), 7.0 (1H, d, J=8.5 Hz, H-5'), 7.67-7.85 (2H, m, H-2', H-6'), 7.5 (lH, d, J=8.5 Hz,H-6), 8.2 (lH, d, J=8.5 Hz, H-5).5'-Methoxypongapin 5. It was also eluted withchloroform-petroleum ether (50:50, v/v), andcrystallized from benzene-petroleum ether toafford white granules'' (150 mg), mp 178-80°C; IR(KBr): 1625, 1600, 1570, 1525, 1505,.1495, 1445,1415, 1380, 1315, 1285, 1040, 1020, 765 ern";MS: m1z 366 (~', 100%),365 (58), 351 (33),326(57),325 (58),175 (16),160 (17), 77 (5); IHNMR(CDCh): 03.90 (3H, s, OCH~, 3), 4.0 (3H, S,OCH3, 5'), 6.10 (2H, s, -OCH2-O), 7.18 (1H, d,J=2 Hz, -OCH=CH-), 7.78 (1H, d, J=2 Hz,-OCH=CH-), 7.38 (lH, d, H-2'), 7.54 (1H, d,H-6'), 7.50 (IH, d, J=8 Hi, H-6), 8.2 (lH, d, J=8Hz, H-5).Kanujin 6. It was obtained from chloroform-petroleum ether (60:40, v/v) eluates, andcrystallized from benzene-petroleum ether aswhitefeatery solid9 (100 mg), mp 204-206°C; IR (KBr):1640, 1620, 1505, 1450, 1395, 1260, 1210, 1130,1055, 1015, 830 em"; MS: m1z 356 (~', 67%),341 (37),325 (24), 311 (15), 176 (5),162 (7),150(20), 63 (30); IR NMR (CDCh): 03.88-3.98 (9H,broad, s, OCR3), 6.07 (2H, s, -OCR~), 8.16(IR, d, H-5), 6.95 (lR, dd;H-6), 6.88 (IH, d, H-8),7.30 (lH, d, H-2'), 7.44 (lH, d, H-6').GJ~-':-ra-1!4. It was obtained from a mixture ofchloroform-petroleum ether (75:25, v/v), andcrystallized from benzene to yiel~ brownish yellowflakes'" (62 mg), mp 256-60°C; IR (KBr): 1630,1585, 1505, 1452, 1435, 1400, 1380, 1352, 1325,1215, 1172, 1100, 1045 ern"; MS: mlz 336 (M",100%), 176 (80), 160 (24), 131 (13), 77 (14);IH NMR (CDCh): 0 4.0 (3H, s, OCH3), 6.10 (2H,s, -OCH2-O-), 6.76 (1H, s, H-3), 7.18 (IR, d,-OCH=CH), 7.75 (1H, d, -O-CH=CH), 7.15 (2H,m, R-2', H-6'), 7.54. (lR, d, J=9.16 Hz, H-6), 8.2(1H, d, J=8.54 Hz, H-5).AcknowledgementFinancial support from CSIR, New Delhi ISgratefully acknowledged.References1 Chopra R N, Nayar S L & Chopra I C, Glossary of IndianMedicinal Plants (CSIR, New Delhi) 1956, p. 94.2 Ghosal S & Mukherjee B, J Org Chem, 31, 1966, 2284.3 Veno A, Ikeya Y, Fukushima S, Noro T, Morinaga K &Kuwano H, Chem Pharm Bull, 26,1978,2411.4 Purushothaman K K, Kishore V M, Narayanaswami V &Connolly J D, J Chem Soc (C), 1971, 2420.S Aneja R, Khanna R N & Seshadri T R, J Chem Soc, 1963,163.6 Rangaswami S & Shastri V B, Curr Sci, 24,1955, 12.7 Row L R, Aust J Scient Res, AS, 1952, 754.8 Garg G P, Sharma N N & Khanna R N, Indian J Chem,16B, 1978,658.9 Malik S B, Seshadri T R & Sharma P, Indian J Chem,14B, 1976,229.10 Mittal 0 P & Seshadri T R, J Chem Soc, 1956, 2176.

Chemical constituents of Desmodium sequax

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Chemical constituents of Desmodium sequax

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