Condensation of carboxylic acids 1 and 5 with unprotected α-amino acids 2 via activation by ethyl chloroformate and triethylamine proceeded effectively to afford the corresponding amides in 50–99% yields. Tripeptide 7c was obtained in 42% yield from the dipeptide 6c in a similar manner.
A convenient protocol for the condensation of carboxylic acids with unprotected α‐amino acids via activation by ethyl chloroformate and triethylamine is presented.
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