Process for the manufacture of benzoxazole, benzthiazole and benzimidazole derivatives

Abstract

Process for the manufacture of a heterocyclic compound of the formula I ##STR1## in which Y denotes a --CN, --COOR' or ##STR2## group, in which R' can be an optionally substituted alkyl or aryl radical and R" and R"' independently of one another can have the same meaning as R' or can be hydrogen or, conjointly with the nitrogen atom, can form a heterocyclic 5-membered or 6-membered ring and X denotes a --S-- or --O-- atom or a --NR"-- group and the ring A can carry non-ionic substituents or optionally substituted fused rings, wherein a nitrile of the formula II nc -- ch.sub.2 -- y (ii) is reacted, in organic solvents, with a lower alcohol of the formula III r -- oh (iii) using a molar ratio of nitrile to alcohol of 1:0.9 to 1:1.2, in the presence of an anhydrous strong acid at temperatures of -10.degree. to +40.degree. C to give an imino-ether salt of the formula IV ##STR3## and the resulting imino-ether salt is subjected, without intermediate isolation thereof, to a condensation reaction with an aromatic amine of the formula V ##STR4## using a molar ratio of nitrile to amine of the formula V of 1:0.8 to 1:1.2, at temperatures of 0.degree. to 120.degree. C to give compounds of the formula I, and in the formulae II to V, A, Y and X have the meaning indicated under formula I, R denotes a lower alkyl radical and Z.sup.- denotes an anion of a strong acid.

Dependencies are inferred from the claim text.