Synthesis and some reactions of naphth[1,2‐ d ]oxazole‐5‐sulfonic acids

Naphth[1,2‐ d ]oxazole‐5‐sulfonic acid ( 1 ) has been prepared by the fusion of 4‐amino‐3‐hydroxynaphthalene‐1‐sulfonic acid with formamide. Interaction of 1 with a number of arenesulfonyl chlorides, aryloxyacetyl chlorides, 1‐naphthyloxyacetyl chloride, and chloroacetyl chloride gave 2‐(arylsulfonyl)‐, 2‐(aryloxyacetyl)‐, 2‐(1‐naphthyloxyacetyl)‐ and 2‐(chloroacetyl)naphth[1,2‐ d ]oxaxole‐5‐sulfonic acids ( 2, 3, 4 and 5 ), respectively. The corresponding sulfonyl chloride of 2 was condensed with amines giving the expected 2‐(arylsulfonyl)‐naphth[1,2‐ d ]oxazole‐5‐sulfonamides ( 6 ). Interaction of 5 with hydrazine gave 2‐hydrazinoacetyl and disubstituted hydrazine derivatives 7 and 8 . Condensation of 7 with aromatic aldehydes yielded substituted hydrazonoacetyl derivatives 9 . Two moles of 5 react with one mole of hydroquinone in dry acetone in the presence of anhydrous potassium carbonate and potassium iodide gave 1,4‐bis[5‐sulfonaphth[1,2‐ d ]oxazol‐2‐ylcarbonyl‐methoxy]benzene ( 10 ).