Structure and transformation of products of the reactions of 2,2″-thiodi-isobutyrophenone with hydrazine

Abstract

The novel course of the reaction of the title dioxo-sulphide (II) with hydrazine is described. In absence of acid none of the expected dihydrothiadiazepine (Ia) could be detected; the major product, a monohydrazone (IV), being accompanied by other products including 2,2,4,4-tetramethyl-1,5-diphenyl-8-oxa-3-thia-6,7-diazabicyclo[3.2.1]octane (III) whose structure was elucidated by spectroscopic and X-ray crystallographic methods: compound (III) crystallises in the triclinic space group P with a= 9·911, b= 15·297, c= 6·257 Å, α= 103·02°, β= 106·15°, γ= 81·17°, Z= 2, and the structure was refined to a final R value of 7·7% for 2055 independent reflections. The thiadiazepine (Ia) could, however, be obtained by treatment of a crude reaction mixture in pyridine with strong mineral acid, or by dehydration of (III) with acetic acid. The reaction of (III) with molecular oxygen gives, depending on temperature, either the ozonide (VI) or the epoxide (VII) in good yield.