Of the many important compounds of phosphorous, phosphorous oxychloride (PO
Cl3) finds tremendous use in organic synthesis. Among the overwhelming majo
rity of reactions of this reagent are Vilsmeier - Haack reaction, Bischeler
-Napieralski reaction, Regiospecific dehydration reaction, formation of het
erocycles such as benzoxazoles, quinazolines, beta-lactams, imidazoles and
many others. It also finds use in the synthesis of aminoacid amides, esters
, lactones, phosphorylation of nucleosides, decarbonylation of alpha-aminoa
cids and peptides.