5H-imidazo[2',1':4,3]imidazo[1,5a]pyridin-6-ium salts and processes for their production

A process for the preparation of a compound having the structure ##STR10## wherein X is H, halogen or methyl;

• Y and Z are each hydrogen, halogen, C.sub.1 -C.sub.6 alkyl hydroxyloweralkyl C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.4 alkylthio, phenoxy, C.sub.1 -C.sub.4 haloalkyl, nitro, cyano, C.sub.1 -C.sub.4 alkylamino, diloweralkylamino or C.sub.1 -C.sub.4 alkylsulfonyl group, or phenyl optionally substituted with one C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen, difluoromethoxy, trifluoromethoxy, 1,1,2,2-tetrafluoroethoxy, C.sub.3 -C.sub.8 straight or branched alkenyloxy optionally substituted with one to three halogens, or C.sub.3 -C.sub.8 straight or branched alkynyloxy optionally substituted with one to three halogens;
• and when taken together Y and Z may form a ring represented by --(CH.sub.2).sub.n --, where n is an integer of 3 or 4, or --(CH).sub.4 --;
• R.sub.1 is C.sub.1 -C.sub.4 alkyl;
• R.sub.2 is C.sub.1 -C.sub.4 alkyl or C.sub.3 --C.sub.6 cycloalkyl;
• and when R.sub.1 and R.sub.2 are taken together with the carbon to which they are attached they may represent C.sub.3 -C.sub.6 cycloalkyl optionally substituted with methyl;
• R.sub.3 is H or lower alkyl optionally substituted by phenyl;
• R.sub.4 and R.sub.5 are each C.sub.1 -C.sub.4 alkyl or phenyl, or when taken together may form a piperidine or pyrrolidine ring;
• and when R.sub.1 and R.sub.2 are not the same the optical isomers thereof;
• comprising the steps of (1) reacting an imidazolin-2-yl pyridine or quinolinecarboxylic acid ester or a carbamoyl pyridine or quinolinecarboxylic acid ester with an approximately equimolar amount of a Vilsmeir reagent, said Vilsmeir reagent comprising a formamide, having the structure R.sub.4 R.sub.5 NCHO wherein R.sub.4 and R.sub.5 are as described above, reacted with phosgene, thionylchloride or POCl.sub.3, and (2) optionally treating the resulting product of step (1) with alcoholic base, followed by (3) acidification and (4) isolation of the product.