NEW MATERIAL:Bis(6-trifluoromethylbenzotriazolo)carbonate of formula I.

USE: An active esterification agent for producing active ester of an amino acid capable of proceeding peptide synthesis in high yield, an agent for introducing a novel carbonate-type of carbamate-type protective group to hydroxyl group (or amino group) and a reagent for the synthesis of an active carbonate compound or active carbamate compound.

PREPARATION: The compound of formula I can be produced by reacting the compound of formula II with the compound of formula III in an organic solvent such as ether. The obtained compound is rapidly reactive with an N-protected amino acid in acetonitrile to form an active ester of an amino acid in high yield. A dipeptide can be produced from the active ester by aminolyzing with another amino acid (protecting carboxylic acid as ester-form) without separating from the former reaction mixture.