1,2-Benzisoxazol-3-yl Diphenyl Phosphate: A New, Reactive Activating Agent for the Synthesis of Amides, Esters, and Peptides via Condensation

Article abstract of DOI:10.1021/jo00206a006

A new activating agent for condensations, 1,2-benzisoxazol-3-yl diphenyl phosphate (1), was readily prepared in high yield by the reaction of 1,2-benzisoxazol-3-ol (2) with diphenyl phosphorochloridate (3) in the presence of triethylamine in benzene.The reaction of the carboxylic acids with the amines in the presence of 1 was investigated by two procedures, a two-step method and a one-step procedure.Both methods gave the corresponding amides and esters in high yields under mild conditions, but the one-step procedure was found to be superior to the two-step procedure because of its simplicity and speed.Furthermore, the activating agent 1 was shown to be a useful peptide forming reagent.