RING TRANSFORMATIONS OF HETEROCYCLIC-COMPOUNDS .14. RING TRANSFORMATIONS OF PYRYLIUM AND THIOPYRYLIUM SALTS WITH ANHYDROBASES DERIVED FROM 1H-BENZIMIDAZOLIUM AND BENZOTHIAZOLIUM SALTS - AN EASY ACCESS TO 2-(2,4,6-TRIARYLPHENYL) 1H-BENZIMIDAZOLIUM AND BENZOTHIAZOLIUM DERIVATIVES

The preparation of former unknown 2-(2,4,6-triarylphenyl) substituted 1H-benzimidazolium perchlorates 7 and benzothiazolium perchlorates 8 f rom 2-methyl substituted derivatives 5/6 by a 2,6-[C-5+C] ring transfo rmation of 2,4,6-triarylpyrylium and 2,4,6-triarylthiopyrylium salts 1 /9 in the presence of an appropriate base (7: sodium ethoxide, 8: sodi um acetate) is reported. Spectroscopic data of the transformation prod ucts and their mode of formation via anhydrobases of the salts 5/6 are discussed.