nan Habib-ur-Rehman

Alkaloids from Rhazya stricta

Abstract Chemical investigations of roots and leaves of Rhazya stricta have resulted in the isolation of the new indole alkaloids, 16 R -19,20- E -isositsirikine acetate, leepacine and dihydroeburnamenine, along with six known alkaloids. Among these, (−)-16 R ,21 R - O -methyleburnamine, 2-ethyl-3[2-(3-ethylpiperidino)ethyl]-indole, (20 S )-19,20-dihydrocondylocarpine and N -acetylaspidospermidine have been isolated for the first time from R. stricta . Spectral studies on (+)-21 S -eburnamenine and the glycoalkaloid strictosamide have also been undertaken.

Rhazimanine, an indole alkaloid from fruits of Rhazya stricta

Abstract A new indole alkaloid, rhazimanine, has been isolated from the fruits of Rhazya stricta. It belongs to the Corynanthe group of alkaloids with a cis-quinolizidine system bearing an H-3 in the β-configuration, equatorial to ring ‘D’. The stereochemistry at various asymmetric centres has been established by a series of NOED measurements.

Alkaloids from Alstonia macrophylla

Abstract A new alkaloid, 19-hydroxyvincamajine, has been isolated from the leaves of Alstonia macrophylla . In addition to this, eight other indole alkaloids, alstonerine, alstophylline, macralstonine, anhydromacralstonine, talcarpine, vincamajine, vincorine and cabucraline, were also isolated and identified from the bark and leaves of A. macrophylla of Sri Lanka. The last five alkaloids have been isolated for the first time from this species and the 13 NMR of alstonerine and alstophylline are reported.

Aspidospermidose: a new dihydroindole alkaloid from the leaves of Rhazya stricta

A new dihydroindole alkaloidal glycoside, aspidospermidose, has been isolated from the leaves of Rhazya stricta, and has been assigned structure (1) on the basis of spectral studies.

Leurosinone: a new binary indole alkaloid from Catharanthus roseus

A new binary indole alkaloid, leurosinone, has been isolated from the leaves of Catharanthus roseus, and has been assigned structure (1) on the basis of spectral studies.