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Bromination of 3,4-dihydro-2H-thiopyran derivatives leads to bromo-substituted 3,4-dihydro-2H-thiopyrans or 4H-thiopyrans, depending on the reaction conditions and the structure of the starting heterocycles.

The reactions of α,β-unsaturated ketones and Lawesson’s reagent with maleic, itaconic, or 5-norbornene-2,3-dicarboxylic acid led to the corresponding 3,4-dihydro-2H-thiopyran anhydrides. As a result of the reaction of methacrylic acid, Lawesson’s reagent, and chalcone, 4-methyl-1,8-diphenyl-2,6-dithiabicyclo[2.2.2]octan-3-one is formed. The selectivity of the acylation of amines using the synthesized anhydrides was studied.

Heterocyclization of toluic acid amidoximes with acetic or propionic anhydrides affords 5-alkyl-3-tolyl-1,2,4-oxadiazoles, whose air oxidation in the same vessel gives (5-alkyl-1,2,4-oxadiazol-3-yl)benzoic acids.