Synthesis and characterization of 4,5-dihydro-1H-pyrazolo[3,4b][1,4]azaphosphinines

Abstract

1,3,3-Trimethyl-2-(1-R-3-methyl-5-pyrazolyliminoethylidene)indolines were shown to undergo phosphorylation with phosphorus(III) halides at the two nucleophilic carbon centers to give fused 1,4-azaphosphinine ring systems. Chemical properties of the synthesized compounds were characterized. For some representative compounds, detailed NMR spectroscopic investigations were performed, including the determination of 31P, 1H and 31P, 13C coupling constants. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 391–398, 1999