Cyclization of dialkylpropyn-1-yl(allyl)(3-isopropenylpropyn-2-yl)ammonium bromides and water-base cleavage of 2,2-dialkyl-5-methyl-2,6,7,7a-tetrahydro-1h-isoindolium and 2,2-dialkyl-5-methylisoindolinium bromides

• Published in: Journal of heterocyclic chemistry 2008-05, Vol.45 (3), p.687-692
• Main Authors: Chukhajian, Emma H., Nalbandyan, Martiros K., Gevorkyan, Hasmik R., Chukhajian, Eliza H., Panosyan, Henrik A., Ayvazyan, Armen G., Tamazyan, Rafael A.
• Format: Article
• Language: English
• ISSN: 0022-152X; 1943-5193
• DOI: 10.1002/jhet.5570450309

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‐dimethylbenzyl‐amines. 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.