Urea Derivatives from Pentadiplandra brazzeana

Four urea derivatives were isolated from the roots of Pentadiplandra brazzeana, and their structures were elucidated by spectroscopic techniques. N-Benzyl-N'-(4-methoxybenzyl)urea (1) is a new compound, although N,N'-di-(4-methoxybenzyl)urea (2), N,N'-dibenzylurea (3), and p-methoxythiobenzaldehyde (4) are reported from a natural source for the first time.