Neolignans and a lignan from Piper clarkii
1995
Prasad, A.K. | Tyagi, O.D. | Wengel, J. | Boll, P.M. | Olsen, C.E. | Bisht, K.S. | Singh, A. | Sarangi, A. | Kumar, R. | Jain, S.C.
Four new compounds, a lignan and three neolignans, together with one known neolignan have been isolated from the leaves and stems of Piper clarkii. Their structures were established on the basis of 1H, 13C and 1H-1H COSY NMR, NOE and mass spectral data and CD curves. The novel lignan was identified as (2S,5S)-diveratryl(3R,4S)-dimethyltetrahydrofuran. The structures of the new neolignans were established as (7R,8R,1'S)-delta 8'-1'-methoxy-3,4-methylenedioxy-1',6'-dihydro-6'-oxo-7.0.4',8.3' lignan [2R,3R,5S)-2-(1,3-benzodioxol-5-yl)-3,5-dihydro-5 methoxy-3-methyl-5-(2-propenyl)-6(2H)-benzofuranone], (7S,8S, 3'R)-delta 8'-3,3',4-trimethoxy-3',6'-dihydro-6'-oxo 7.0.4',8.3'-lignan [2S,3S,3aR)2-(3,4-dimethoxyphenyl) 3,3a-dihydro-3a-methoxy-3-methyl-5(2-propenyl)-6(2H) benzofuranone] and rel(7S,8S,1'R, 3'R)-delta 8'-5'-methoxy-3,4-methylenedioxy-1',2', 3',4'-tetrahydro-2',4'4-dioxo-7.3',8.1'-lignan [(7S,6S, 5R,1R)7-(1,3-benzodioxol-5-yl)-3-methoxy-6-methyl 5-(2-propenyl)bicyclo[3.2.1]oct-3-ene-2,8-dione]. The known neolignan has been identified as denudatin B.
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