H. Matschiner et al., REACTION OF ARYLMETHYLKETONES WITH SULFUR , SECONDARY-AMINES AND SULFUR-DIOXIDE, Phosphorus, sulfur and silicon and the related elements, 84(1-4), 1993, pp. 223-230
The acetophenones 2 react with different sulfurdioxide-secondary amine
adducts 1 and sulfur to yield the red-coloured zwitterionic 2-iminio-
dithioacetates 3. Enamines can be proved to be intermediates in this r
eaction. Thus enamines 5 and other derivatives such as acetophenone an
il, acetophenone diethyl acetal and diphenacyl sulfide also give 3, In
the absence of 1, 3a react with hydrogen sulfide to form the thioamid
e of phenylacetic acid 8.