Phosporylation of 1,3-di(N-alkyl)azoles by phosphorus(V) acid chlorides - A route to potential haptens derived from phosphinic acids

Article abstract of DOI:10.1016/0040-4020(95)00797-C

Phosphorylation of N-alkylated imidazoles and benzimidazoles at C-2 by CH₃POCl₂, PhPOCl₂, POCl₃ in pyridine-triethylamine solution is described. The formed heteroaryl-substituted phosphinic or phosphonic acid chlorides were transformed without isolation into the corresponding phosphinic (phosphinic) acids, their salts or amides with moderate yields. This reaction opens a simple way to potential haptens derived from phosphinic acids. These haptens mimic tetrahedral transition state of many reactions and can be used to obtain catalytic antibodies. The functionalized heteroarylsubstituted phosphinic acids which have been used as hapten precursors were obtained by phosphorylation of 1-alkyl-5-nitrobenzimidazole or by usage of a new phosphorylating reagent - (4-trichloromethylphenyl)phosphonic dichloride.