Selective Bromination of Dehydroacetic Acid with N-Bromosuccinimide

Abstract

Bromination of dehydroacetic acid has been carried out with N-bromosuccinimide under various conditions. The reactions led to selective bromination, thereby offering efficient synthesis of 3β-bromodehydroacetic acid (3), 3β,5-dibromodehydroacetic acid (4), 3β,3β-dibromodehydroacetic acid (5), and 3β,3β,5-tribromodehydroacetic acid (6).

GRAPHICAL ABSTRACT

Keywords:

• 3-Acetyl-4-hydroxy-6-methyl-2H-pyran-2-one
• α-bromo ketones
• dehydroacetic acid
• α,α-dibromoketones
• microwave irradiation
• N-bromosuccinimide

ACKNOWLEDGMENT

We are thankful to the Council of Scientific and Industrial Research, New Delhi, for the award of a junior research fellowship to Poonam Lohan to carry out this work.

Notes

^a Yields of isolated products with regard to NBS.

^a Condition (i), NBS/CH₃CN/p-TsOH; condition (ii), NBS/p-TsOH/conventional heating; and condition (iii), NBS/p-TsOH/microwave irradiation.

^b Yields of isolated products w.r.t NBS.