1-Hydroxybenzotriazole monohydrate

1-Hydroxybenzotriazole monohydrate, commonly abbreviated as HOBt or HOBt hydrate (CAS 80029-43-2, EC 806-689-1), is a heterocyclic compound used as a coupling reagent auxiliary in synthetic chemistry. It carries no assigned E-code and is commercially recognised under the abbreviations HOBT and HOBT H2O.

HOBt monohydrate functions primarily as a racemisation suppressant and activation catalyst in peptide bond formation. By reacting with activated carboxylic acid intermediates to form stable, reactive esters, it accelerates amide coupling while minimising epimerisation of chiral amino acid residues. This mechanism makes it a standard reagent in solid-phase and solution-phase peptide synthesis.

The compound is supplied as a powder to crystalline solid and is subject to REACH registration requirements for European commerce. Procurement teams should confirm purity grade specifications aligned with pharmaceutical manufacturing standards. Packaging formats vary by supplier and order volume; buyers should request a current safety data sheet and certificate of analysis.