Hydroxybenzotriazole (abbreviated HOBt) is an organic compound that is a derivative of benzotriazole. It is a white crystalline powder, which as a commercial product contains some water (~11.7% wt as the HOBt monohydrate crystal).
H 1591 (OTTO) 1-Hydroxy benzotriazole, hydrate, 98% Cas 123333-53-9 - used for the synthesis of amides from carboxylic acids aside from amino acids. These substrates may not be convertible to the acyl chlorides.