CATALYSIS BY PHOSPHORUS AND SILICON COMPOUNDS IN THE SYNTHESIS OF OXYNAPHTOIC ACID ANILIDES

Catalysis of the acylation aniline with 3-­hydroxy-2-naphthoic, 1-hydroxy-2-naphthoic, 2-hydroxy-1-naphthoic and 1-hydroxy-4-naphthoic acids by phosphorus P(III) silicon Si(IV) compounds leads to formation anilides corresponding hydroxy­naphthoic under mild conditions (ortho-xylene, 146.5–147 °C) in almost quantitative yield.
 Among trichloride tribromide; phosphorous, 1-hydroxyethyli­de­ne-di­phos­phonic, pyrophosphorous me­ta­phos­phorous acids; trimethyl-, dimethyl- diethylphosphites; phosph(III)azan proved be active catalysts; among – tri­chloro-(methyl)silane, dichloro(ethyl)silane, dichloro­(dimethyl)silane, tetrachlorosilane tet­ra­ethoxysilane are active.
 The catalysts were used an amount only 2% mole. from hydroxynaphthoic acid, which is 15–35 times less than conventional use same as condensing agents synthesis carboxylic acid arylamides. P(V) compounds, thionyl chloride, sulfuryl chloride practically do not exhibit catalytic activity. presence activity capable forming phosphorous reaction mass, does contradict previously proposed mechanism P = O-nucleophilic catalysis for substituted benzoic catalyzed PCl3.
 In general, preparation hydroxybenzoic successfully complements range catalysts, based on Ti(IV) naphthoic (containing no aromatically bonded hydroxy group), allowing create a universal method their synthesis.