SYNTHESIS OF PHOSPHORUS-CONTAINING HETEROCYCLES FROM 2-AMINONICOTINIC ACID

The reaction of 2-aminonicotinic acid with ethyl chloroformate, followed by alkylation with NaH/MeI and decarboxylation with methylamine, led to N-methyl-2-(methylamino)nicotinamide (3). Treatment of 3 with PCl3 in the presence of triethylamine gave the phosphorinanone 4. Substitution of chlorine in 4 by the dimethylamino-, N,N,N'-trimethylethylenediamino-, or bis(2-chloroethyl)amino group furnished 5-7. Hydrolysis of 4 with small amounts of water formed the phosphoryl derivative 8 as the hydrochloride. The spirophosphoranes 9 and 10 were produced by reaction of 5 with hexafluoroacetone and tetrachloro-o-benzoquinone, respectively. In order to evaluate its coordination ability, the N,N,N'-trimethylethylenediamino-substituted diazaphosphorinanone 6 was allowed to react with the tetracarbonyl norbornadiene derivatives of chromium(0) and molybdenum(0). The cis-substituted tetracarbonyl complexes 12 and 13 were formed. In the reaction of 7 with dichloro(1,5-cyclooctadiene)platinum(II) the cis-disubstituted complex 15 was formed. A comparison of benzo- and pyrido-annulated phosphorinanones was made, and their differences were discussed. In the case of the compounds 2, 7, and 9 single-crystal X-ray structure analyes were performed. In 9 the heterocycle C and N atoms are coplanar (the phosphorus Lies 60 pm outside the plane); P and N(2) are displaced in 7 to the same side of the plane of the remaining four atoms.