Improved Method for the Preparation of Oxadiazoles from Diacyl Hydrazines

Abstract

N-methylimidazole (NMI) is used as the base in the triflic anhydride (Tf₂O)–mediated formation of oxadiazoles from diacyl hydrazines. This reagent is superior to pyridine-derived bases in terms of cost and reaction profile.

Keywords:

• Cyclization
• dehydration
• oxadiazoles

ACKNOWLEDGMENT

Thanks go to Mike Kinns for spectroscopic studies elucidating the structure of compound 5.

Notes

^a Refers to isolated yield of pure material.

^b Compound 3c was a 1:1 mixture of (2S, 4 R)- and (2S, 4S)-diastereomers. Stereochemistry at C-2 was not affected by the reaction.