Novel and Expedient Regioselective Synthesis of 2-Imino-3-methyl-2,3-dihydrothiazoles

Abstract

Cyclization of α-tosyloxyacetophenones 1 and N-methylthiourea 2 in acidic medium affords a novel and expedient method to synthesize 2-imino-3-methyl-2,3-dihydrothiazoles 3 with excellent level of regiocontrol.

Keywords:

• Acidic medium
• 2-imino-3-methyl-2,3-dihydrothiazoles
• N-methylthiourea
• Regioselective synthesis
• α-tosyloxyacetophenones

ACKNOWLEDGMENTS

We thank the Council of Scientific and Industrial Research, New Delhi, for financial assistance and a junior research fellowship to Rajiv Kumar. Thanks are also due to Sophisticated Analytical Instrumentation Facility, Central Drug Research Institute (RSIC, CDRI), Lucknow, India, for providing elemental analysis. We also thank Professor S. P. Singh for helpful suggestions.

Notes

^a Ratio calculated from the ¹H NMR of the crude reaction mixture.

^a Ratio calculated from the ¹H NMR of the crude reaction mixture.

^b Isolated yields.