A Convenient Synthesis of Amides with 2-Halo-2,3-dihydro-1,3,4,2-oxadiazaphospholes as New Condensing Agents

Abstract

Various amides, including some with bulky substituents, are prepared in good yields from free carboxylic acids and amines under mild conditions by a one-step method using new condensing agents 2-halo-2,3-dihydro-1,3,4,2-oxadiazaphospholes, especially 5-methyl-2-chloro-3-phenyl-2,3-dihydro-1,3,4,2-oxadiazaphosphole.

A New Method for Transcarbamation and Amidation from Benzyl Carbamate

“…an acyl chloride that is then allowed to react with amine in presence of metal 13 or tertiary amine 14 . Attempts have also been made to prepare amide directly from acid using acid activator such as dialkylphosphochloriate 15 , phosphorous-complex 16 , benzoxazole-sulfur dimer 17 , EDC/HOBT 18 . Amides are directly prepared from alcohol 19 , nitrile 20 , oximes 21 , alkane 22 , alkyne 23 , boric acid 24 and thioamide 25 .…”