2-Oxo-2-polyfluoroalkylethane-1-sulfones and -sulfamides in the Biginelli and ‘retro-Biginelli’ reactions

2-Oxo-2-polyfluoroalkylethane-1-sulfones and -sulfamides react with aryl aldehydes and urea under Biginelli reaction conditions to yield 4-hydroxy-4-polyfluoroalkyl-5-sulfonyl-6-aryl-tetrahydropyrimidinones. The latter compounds on reaction with hexamethylenetetramine (HMTA) under thermal conditions undergo ‘retro-Biginelli’ reaction involving replacement of the 6-aryl substituent of the pyrimidinone cycle with a hydrogen atom donated by HMTA. Hexamethylenetetramine was employed for the first time in place of formaldehyde in the reported one-step Biginelli protocol for the synthesis of fluorinated sulfonyl-containing 6-unsubstituted tetrahydropyrimidinones.