The Action of Carbon Disulfide and Sulfur on Enamines, Ketimines, and CH Acids

Abstract

Abstract The reaction of sulfur, carbon disulfide, and enamines at room temperature leads mainly or exclusively to 3H‐1,2‐dithiole‐3‐thiones; these are occasionally accompanied by 2H‐1,3‐dithiole‐2‐thiones, which can also be prepared by a modified procedure. Many enamines react with sulfur at room temperature to form thioamides. At about 50°C, enamines of acetophenone give 2‐benzylidene‐4‐phenyl‐2H‐1,3‐dithiol. The action of isothiocyanates and sulfur on enamines leads to the formation of thiazolidine‐2‐thiones. 2H‐Thiopyran‐2‐thiones can be prepaAred from enamines or dienamines with carbon disulfide at room temperature. The reaction of ketimines (Schiff bases) with carbon disulfide and sulfur yields 3H‐1,2‐dithiole‐3‐thiones or isothiazoline‐5‐thiones. The reaction of alkynes with sulfur and carbon disulfide leads to 2H‐1,3‐dithiole‐2‐thiones. Nitriles containing active methylene groups react with carbon disulfide and sulfur to form 5‐amino‐3H‐1,2‐dithiole‐3‐thiones. When isothiocyanates are used instead of CS 2 , the reaction leads to δ 4 ‐4‐amino‐thiazoline‐2‐thiones.