One‐Pot Synthesis of (5‐Aminopyrazol‐4‐yl)‐phoshonic Acid Derivatives from 1‐Aryl‐5‐arylcarboxamidopyrazoles Through Pyrazolo[4,3‐c][1,5,2]oxazaphosphinines.

Abstract

4,3-c][1,5,2]oxazaphosphinines. -Substrates (I) and (XVII) react with PBr3 or Ph-PCl2 to yield a new heterocyclic system, i.e. the pyrazolooxaphosphinimines (II), (IV) and (XVIII). Their reaction with nucleophiles or electrophiles is studied. -(VOLOCHNYUK*, D. M.; PUSHECHNIKOV, A. O.; KROTKO, D. G.; KOYDAN, G. N.; MARCHENKO, A. P.; CHERNEGA, A. N.; PINCHUK, A. M.; TOLMACHEV, A. A.; Synthesis 2003, 6, 906-914; Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, Ukraine; Eng.) -Mais 35-104