?ATALYTIC METHOD FOR THE SYNTHESIS OF 3-HYDROXY-2-NAPHTOIC ACID ANILIDE

Arylamides of 3-hydroxy-2-naphthoic acid are widely used in the production organic azo pigments, as medicines and pesticides.
 Titanium tetrachloride, tetrabutoxytitanium polybutoxytitanates, previously for synthesis most important them., anilide by boiling latter aniline (184 °C), proved to be ineffective catalysts carrying out this reaction ortho-xylene.
 The study reasons inhibition catalysis showed that it can associated with interaction Ti(4+) hydroxy group acid, its oxidation, accompanied a decrease effective charge titanium.
 Taking into account inhibition, search new anilide, known literature data on oxidizing ability (according values rate constant k) respect phenoxyl radicals number Lewis acids, including titanium were used:
 SbCl5>TiCl4 >SnCl4>PCl5>AlCl3
 k, l·mol-1·sec-1 105 157 156 42 18.
 This made possible choose phosphorus trichloride an catalyst. It is shown compound, amount only 2% mole. from allows ortho-xylene (145 under relatively mild conditions, compared °?), obtain (by aniline) good quality practically quantitative yield.
 Antimony trifluoride also has similar pro­perties catalyst, at level efficiency trichloride.
 act agent should, apparently, always taken during catalytic amidation aromatic oxycarboxylic acids elevated temperatures.