Darstellung von phosphorhaltigen Heterocyclen aus 2‐Aminonicotinsäure

Synthesis of Phosphorus‐Containing Heterocycles from 2‐Aminonicotinic Acid The reaction of 2‐aminonicotinic acid with ethyl chloroformate, followed by alkylation with NaH/Mel and decarboxylation with methylamine, led to N ‐methyl‐2‐(methylamino)nicotinamide ( 3 ). Treatment of 3 with PCl 3 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 singlecrystal 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.