The structural determination of five new coumarins: murralonginol isovalerate (1 b), isomurralonginol isovalerate (2b), murrangatin isovalerate (6b), minumicrolin isovalerate (7b), chloculol (4a), and a new indole alkaloid, paniculol (1 8), is described.The relative configurations hitherto reported for the a-glycol moieties in murrangatin (erythro) and minumicrolin (threo) have been revised to threo for compound (6a) and erythro for compound (7a), respectively on the basis of NOE experiments performed on the acetonides (6e) and (7e). Furthermore, the absolute configuration of (-)-murrangatin (6a) has been shown to be [R, R] by analysis of the CD spectrum of tetrahydromurrangatin dibenzoate (1 6b). The reaction of phebalosin ( 8) with hydrochloric acid has also been re-examined.We have systematically studied the chemical constituents of Rutaceous plants.' Furukawa has reported on the chemical composition of the leaves of Murraya paniculata (L.) Jack,lb collected in the Iriomote Islands, Okinawa, Japan, and on leaves of M . exotica L."," cultivated at Higashiyama Zoo and Botanical Garden, Nagoya, Japan.M. paniculata (L.) Jack., and M . exotica L., grow in Southern Asia as shrubs. The M . exotica plant had hitherto been considered to be identical with M . paniculata.2 However, recent investigations have led to the proposal that this species be reinstated as a distinct taxon. Moreover, both plants have been used as indigenous drugs in India. In these circumstances, the study of the chemical composition of M . paniculata is of some interest.Many research groups 3,5-7 have found that M . paniculata contains several kinds of coumarins and indole alkaloids. In this report, we describe the structural elucidation of five new coumarins: murralonginol isovalerate (lb), isomurralonginol isovalerate (2b), chloculol (4a), murrangatin isovalerate (6b), minumicrolin isovalerate (7b), and a new indole alkaloid, paniculol (18), derived from the root bark of M . paniculata collected at Ishigaki Island, Okinawa, in May.Furthermore, we report on a revision of the reported relative configurations of the a-glycol systems from (-)-murrangatin (erythro) and (+)-minumicrolin (threo) to threo for compound (6a) and erythro for compound (7a) basis of NOE experiments performed on their acetonides [compounds (6) and (7e)I. That the absolute configuration of (-)-murrangatin (6a) is [R, R ] was confirmed by analysis of the C D spectrum of tetrahydromurrangatin dibenzoate (16b), and a re-examination of the behaviour of phebalosin (8) on treatment with hydrochloric acid is described.
