CAS Registry Number

CAS 26725-51-9 — 4-Hydroxybenzotriazole

4-Hydroxybenzotriazole (4-HOBt) is a versatile heterocyclic compound widely used as a coupling reagent in peptide synthesis and organic chemistry to improve reaction efficiency. It enhances amide bond formation in carbodiimide-mediated reactions, reducing side effects. This white to off-white crystalline solid has a CAS number of 26725-51-9, a molecular formula of C6H5N3O, and a molecular weight of 135.12 g/mol. It is stable at ambient storage conditions and carries no signal word for hazard classification. Molekula supplies 4-Hydroxybenzotriazole from research to bulk quantities with full documentation and ISO 9001:2015 traceability.