Reactions with asymmetric diarylethanes and diarylethylenes. Part XIII. Rearrangements of 1,1-dihalogeno-2,2-diarylethanes and the corresponding 1-halogenoethylenes in boiling ethylene glycol, alone or in the presence of sodium 2-hydroxyethoxide

Abstract

1,1-Dihalogeno-2,2-di-p-tolylethane in boiling ethylene glycol (98%) gave the corresponding 1-halogenoethylene, the corresponding stilbene, the cyclic acetal 1,1-ethylenedioxy-2,2-di-p-tolylethane, 4,4′-dimethyldeoxybenzoin, di-p-tolylacetaldehyde, and 4,4′-dimethylbenzophenone. The last three compounds are also formed when a solution of the acetal in acidified ethylene glycol (98%) is boiled. The 1-halogenoethylene gave the deoxybenzoin and a trace of 1,1-di-p-tolylethylene in boiling ethylene glycol. 1,1-Dichloro-2,2-bis-p-bromophenyl-(or 2,2-bis-p-chlorophenyl)-ethane underwent partial dehydrochlorination.

1,1-Dihalogeno-2,2-di-p-tolylethane, and the corresponding 1-halogenoethylene, with sodium 2-hydroxyethoxide in boiling ethylene glycol (98%) gave di-p-tolylacetylene and traces of the cyclic acetal and ditolylacetic acid. 1,1-Dichloro-2,2-bis-p-bromo-(or 2,2-bis-p-chloro)-phenylethane, and the 1-chloroethylene gave the cyclic acetal, 1,1-bis-p-chlorophenyl-2-(2-hydroxyethoxy)ethylene, bis-p-chlorophenylacetic acid, and bis-p-chlorophenylmethane. The 1-bromoethylene gave in addition a trace of bis-p-bromo-(or chloro)-phenylacetylene.