New aspects in the base-promoted cyclisation of o-vinylbenzohydrazonyl chlorides
Abstract
Treatment of the title hydrazonyl chlorides with sodium azide, sodium cyanide, and sodium acetate in benzene–water (hexadecyltributylphosphonium bromide as phase-transfer catalyst, temperature 25–40 °C) gave 5-azido-, 5-cyano-, and 5-hydroxy-4,5-dihydro-1H-1,2-benzodiazepines; the related fully unsaturated 1H-1,2-benzodiazepines were also formed.