Reactions of heterocyclic polycarbonyl compounds with trialkyl phosphites

Abstract

The reaction of isoquinolinetriones with trialkyl phosphites was investigated and the course of this reaction was monitored by $^{31}P$ NMR spectroscopy. Major products here obtained appeared to be trialkyl phosphate and a condensation dimer, 1,3 (2H,4H)-isoquinolinedion-4-ylidene derivative, formed by the elimination of oxygen of starting material. As a consequence of this investigation it was likely that a mechanism involving carbene intermediate followed by the formation of trialkoxy-phosphorane was reasonable for the formation of trialkyl phosphate and 1,3(2H,4H)-isoquinolinedion-4-ylidene derivative. The reaction of 1,3 (2H,4H)-isoquinolinedion-4-ylidene derivatives with trialkyl phosphites in the presence of water afforded reduction products shown to be 1,3 (2H,4H)-isoquinolinedion-4-yl derivatives by the spectral data and X-ray crystallography. The mass spectra of a series of isoquinolinetriones at 70 eV were obtained and the similarities and differences of their characteristic fragmentations were investigated.