Dialkylpropyn-1-yl(or allyl)(3-isopropenylpropyn-2-yl)ammonium bromides under base-catalyzed condition instantly undergo intramolecular cyclization. The cyclization of dialkylpropyn-1-yl(3-isopropenylpropyn-2-yl)ammonium bromides leads to the formation of 2,2-dialkyl-5-methylisoindolinium salts. In case of allyl analogs, instead of the expected 2,2-dialkyl-6-methyl-3a,4-dihydroisoindolinium salts their isomeric forms -2,2-dialkyl-5-methyl-2,6,7,7a-tetrahydro-1H-isoindolium bromides are obtained. In alkaline medium they are transform into the dihydroisoindolinium salts, the cleavage of which in two directions -1,2 and 1,6 leads to the mixture of isomeric dialkyl-1,4-dimethyl-and 2,4-dimethylbenzylamines.Study of the behavior of 2,2-dialkyl-5-methylisoindolinium salts under conditions of water-base cleavage showed, that only spiro[5-methylisoindolyn]morpholinium bromide undergoes 1,2-elimination, forming 5-methylisoindoline 2-vinyl ethyl ester.

6,7,7a-tetrahydro--1H-isoindolium and 2,2-Dialkyl-5-methyl-isoindolinium Bromide. -The treatment of bromides (I) with catalytic amounts of alkali leads selectively to the isoindolinium salts (II). The latter suffer ring opening furnishing amines (III) and (IV) under the action of excess of KOH. A similar water-base cleavage of bromides (VI) is not observed. -(CHUKHAJIAN*, E. H.; NALBANDYAN, M. K.; GEVORKYAN, H. R.; CHUKHAJIAN, E. H.; PANOSYAN, H. A.; AYVAZYAN, A. G.; TAMAZYAN, R.