Piperonal prepn. - by reacting (1,2)-methylene-di:oxy-benzene with a (N)-alkyl-formanilide and a condensing agent

摘要

Prepn. of piperonal of formula (III) useful as flavour for deodorants or raw material for pharmaceuticals or agricultural chemicals comprises reacting 1,2-methylenedioxybenzene of formula (II) with an N-alkylformanilide of formula (I) and, as a condensing agent, P oxychloride, phosgene, etc. (R is 1-4C alkyl group) Piperonal can be obtd. at high yield and high selectivity. The by-produced monoalkylaniline (IV) can easily be recovered and is reacted with formic acid to prepare the N-alkylformanilide (I).