Beitr�ge zur Chemie der Enaminoketone, 15. Mitt.: Die Dreikomponentensynthese von Hydrazinomethylenchromandionen und eine reduktive N-N-Bindungsspaltung von Phenylhydrazin
摘要:
The three-component reaction of 4-hydroxycoumarin, ethylorthoformiate, and different substituted hydrazines is described. p-Nitrophenylhydrazine, hydrazides and phenylsemicarbazide lead to the expected hydrazinomethylene-chromandiones 2a-f. Reaction of 4-hydroxycoumarin, ethylorthoformiate, and phenylhydrazine or p-tolyl-hydrazine does not yield 2, but the anilino-methylene-chromandiones 6a-b. This indicates a reductive N-N bond cleavage to aniline and ammonia under mild conditions.