The activating effects of arylazo groups on a double bond. Preparation and properties of some bis(diaikylamino)arylazoethenes and related compounds

Abstract

The 1,1-dichloro-2-arylazoethenes (1) readily undergo conjugate addition–elimination reactions with amines to give the new azo-olefins (3). The n.m.r. and electronic spectra of these compounds, which are highly coloured crystalline solids, indicate that they are strongly polarised enamines. The azo-olefin (3h) is formed from compound (1a) and thiophenol in sodium hydroxide, but in the presence of sodium carbonate the hydrazone (8a) is formed instead. 4-Chlorophenol gives the analogous hydrazone (8b). Compound (3h) is reduced by thiophenol to the hydrazone (9).