Process for the manufacture of aliphatically or cyclo-aliphatically substituted 1,2,4-trithiolanes

摘要

Aliphatic or cycloaliphatic substituted 1,2,4- trithiolanes are prepared by reacting an aliphatic aldehyde containing 2 or more carbon atoms or an aliphatic or cycloaliphatic ketone with sulphur and hydrogen sulphide in the presence of ammonia or an amine at low temperatures, preferably in the range 0 DEG C.-10 DEG C. The reaction takes place as follows when butanone is used as starting material FORM:0898574/IV (b)/1 Preferably hydrogen sulphide is introduced at 0 DEG C. into a mixture of 2 moles of the aldehyde or ketone and 1-2 moles of amine, and 1 gm/atom of sulphur is then added gradually. When ammonia is used it is preferred for equal volumes of ammonia and hydrogen sulphide to be first introduced into the aldehyde or ketone. The trithiolanes when treated with an amine decompose to give imines, hydrogen sulphide and sulphur. Examples are given of the preparation of (a) 3,3,5,5-tetraethyl-1,2,4-trithiolane from diethyl ketone; (b) 3,5-dimethyl-3,5-di-n-propyl-1,2,4-trithiolane from methyl propyl ketone; (c) bis - 3,3,5,5 - pentamethylene - 1,2,4 - trithiolane from cyclo-hexanone; (d) 3,3,5,5-tetramethyl-1,2,4-trithiolane from acetone; and (e) 3,5-di-n-propyl-1,2,4-trithiolane from butyraldehyde. In the preparation of 3,3,5,5-tetramethyl-1,2,4-trithiolane some duplo-di-thio-acetone of formula FORM:0898574/IV (b)/2 is also formed.