A new C6-C3 compound from Cassia grandis.

A new compound trans-3-methoxy-4,5-methylene-dioxycinnamaldehyde (1) has been isolated from the aerial parts of Cassia grandis (Caesalpiniaceae) along with the known compounds aloe emodin, centaureidin, catechin, myristicin, 2,4-dihydroxybenzaldehyde, 3,4,5-trimethoxybenzaldehyde, 2,4,6-trimethoxybenzaldehyde, and beta-sitosterol. The structure of 1 was determined by spectral methods.