Efficient Method for Thioacetalization of Carbonyl Compounds in the Presence of a Catalytic Amount of Benzyltriphenylphosphonium Tribromide (BTPTB) under Solvent-Free Conditions

Abstract

A variety of carbonyl compounds have been successfully converted to the corresponding thioacetal derivatives in good to excellent yields on reaction of carbonyl compounds with 1,2-ethanedithiole, 1,3-propanedithiol, and ethylthiol in the presence of a catalytic amount of benzyltriphenylphosphonium tribromide (BTPTB) under solvent-free conditions. Some of the major advantages of this method are mild reaction conditions, high efficiency, and the compatibility with other reported methods. In addition, no bromination occurs at the double bond or α to the keto position or even in the aromatic ring under these experimental conditions.

Keywords:

• Carbonyl compounds
• solvent-free
• thioacetalization

ACKNOWLEDGMENTS

We gratefully acknowledge the funding support received for this project from the Isfahan University of Technology (IUT), I.R. Iran (A. R. H.), and Grants GM 033138, MH 065503, and NS 033650 (A. E. R.) from the National Institutes of Health, USA. Further financial support from Center of Excellency in Sensor Research (IUT) is gratefully acknowledged.

Notes

^a Confirmed by comparison with authentic samples (TLC, GC, IR, and ¹H NMR).

^b Yield of isolated pure product after purification.

^a Confirmed by comparison with authentic samples (TLC, GC, IR, and NMR).

^b Molar ratio of 1:4 (1:1).

^b Yield of isolated pure product after purification.