Synthese von 4-Benzylthio- und 4-(Arylthio)-1,3-oxazol-5(2H)-onen

Article abstract of DOI:10.1002/hlca.19870700518

Following a known procedure, 4-(benzylthio)-1,3-oxazol-5(2H)-one (4a) was synthesized starting from sodium cyanodithioformate (1) and cyclohexanone (Scheme 1).The structure of the intermediate 4-(benzylthio)-1,3-thiazol-5(2H)-one (3a) was established by X-ray crystallography.An alternative route was developed for the synthesis of 4-(arylthio)-1,3-oxazol-5(2H)-ones which are not accessible by the former reaction.Treatment of ethy cyanoformate (5) with a thiophenol in the presence of catalytic amounts of Et2NH and TiCl4, followed by addition of a ketone anf BF3*Et2O in a one-pot-reaction, gave 4f-i in low-toair yields (Scheme 3).Both synthetic pathways - complementary as for benzyl-S aryl-S derivatives seem to be limited with respect to variation of substituents of the ketone.