A Straightforward Synthesis Of 5-Sulfonamidomethyl Substituted 4,7-Dihydroazolo[1,5-A]Pyrimidines

4,7-Dihydroazolo[1,5-a]pyrimidin-5-ylmethanesulfonamides are side-products of the three-component Biginelli-like reaction of aminoazoles, aldehydes andN,N-dialkyl-2-ketomethanesulfonamides. Herein, we report a straightforward synthesis of 5-sulfonamidomethyl substituted 4,7-dihydroazolo[1,5-a]pyrimidines by a two-component condensation of aminoazoles andN,N-dialkyl(cinnamoyl)methanesulfonamides in DMF at reflux. The startingN,N-dialkyl-2-ketomethanesulfonamides can be obtained by either lithiation ofN,N-dialkylmethanesulfonamides and reaction with aldehydes followed by oxidation of the resulting alcohols or by Claisen condensation ofN,N-dialkylmethanesulfonamides with the corresponding esters. The chemical structures of all synthesized compounds are supported by(1)H and(13)C NMR-spectroscopy, mass spectrometry and elemental analysis.