Phosphorus derivatives of amide oximes. Part 1. Synthesis of N2-[bis(dimethylamino)phosphinoyl]amidines, 4,6-disubstituted 2,5-dihydro-1,3,5,2-triazaphosphorine 2-oxides, and 3-dialkylamino-1-dimethylamino-1H-2,1-benzazaphosphole 2-oxides

Abstract

The reactions of tris(dimethylamino)phosphine with amide oximes gave three types of compound, depending on the amide oxime substituents and the temperature: N²-[bis(dimethylamino)phosphinoyl]amidines (1), 4,6-disubstituted 2,5-dihydro-1,3,5,2-triazaphosphorine 2-oxides (2), and 3-dialkylamino-1-dimethylamino-1H-2,1-benzazaphosphole 2-oxides (3). With unsubstituted amide oximes only compounds (1) were formed at room temperature; at 80 °C a 1 : 1 mixture of (1) and (2) was obtained. Compounds (3) were obtained only with N-alkylbenzamide oximes. The formation of compounds (1)–(3) can be explained in terms of an unstable CN–O–P^III intermediate. ³¹P CIDNP effects were observed during the formation of compounds (3), in support of a radical mechanism. ¹H N.m.r. and i.r. data are discussed.