HOBt (1-Hydroxybenzotriazole; CAS 2592-95-2) is an organic benzotriazole derivative extensively utilized in peptide chemistry. Structurally, it is characterized as a crystalline powder typically containing bound water molecules (approximately 11.7% by weight). Functionally, HOBt serves as a racemization inhibitor during peptide coupling, minimizing epimerization of stereocenters. In peptide synthesis, it participates in the generation of reactive ester intermediates, such as N-hydroxysuccinimide esters. These activated esters react under mild conditions with amino groups, facilitating efficient amide bond formation. Additionally, HOBt enables preparation of amide analogues from carboxylic acids not readily convertible into acyl chlorides, thus expanding synthesis options for antibiotic derivatives and related bioactive molecules.

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