Unsaturated carboxylic acids in the one-pot synthesis of novel derivatives of 3,4-dihydro-2H-thiopyran

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.