3-1-BENZOXAZIN-4-ONES, 3,1-BENZOTHIAZIN-4-ONES AND N-ARYLCYANOTHIOFORMAMIDES

Anthranilic acid and 4,5-dichloro-1,2,3-dithiazolium chloride 1 give t he delicate dithiazoloimino carboxylic acid 8 which on mild thermolysi s gives 2-cyano-3,1-benzoxazin-4-one 6 and with triphenylphosphine giv es 2-cyano-3,1-benzothiazin-4-one 7, both quantitatively; in general N -aryliminodithiazoles 2 with triphenylphosphine give the corresponding cyanothioformanilides 3, providing a route to these compounds from an ilines in two mild steps.