Phosphorylation of C-alkenylsubstituted pyrazoles with phosphorus pentachloride

Abstract

The reaction of phosphorus pentachloride with styrenes affords unsaturated organophosphorus compounds in which the phosphorus chloride substituent is attached to the carbon atom of the double bond [1]. NVinylsubstituted azoles are also phosphorylated at the double bond [2–3]. Phosphorylation of С-alkenylazoles with phosphorus pentachloride was not studied until now. The presence in the azole cycles the “pyridine” nitrogen atoms with enhanced nucleophilicity could direct the attack of phosphorus pentachloride to the heterocycle rather than to the double bond of Сvinylazoles to give donor–acceptor complexes. Indeed, the reaction of phosphorus pentachloride with 1-allyl3,5-dimethylpyrazole led to formation of the donor– acceptor complex I. DOI: 10.1134/S1070363209060358