Butadiene sulphone chemistry. Part III. Condensation reactions of butadiene sulphone
2,5-Dihydrothiophen dioxide reacts with aliphatic ketones to give di-condensation products [e.g., (II)] and monosubstitution products [e.g., (III) and (IV)] with a carbinol group either at the 5- or at the 4-position. The structures are confirmed by physical means and independent syntheses of the hydrogenated carbinols. From aromatic aldehydes the di-condensation products only are obtained. Acrylonitrile reacts with 2,5-dihydrothiophen dioxide to give the tetra-cyanoethylated product (V), which readily eliminates sulphur dioxide to give a diene (VI). A new way of removing sulphur dioxide from (II) by heating with aqueous hydrazine gives a dihydrazinodiene (VII) with evolution of hydrogen sulphide.