Reactions of 1,2-dimethyl-3-arylsulfonyl-4,5-dihydro-3H-imidazol-1-ium iodides with bifunctional nucleophiles

The reaction of imidazolium salts, represented by 1,2-dimethyl-3-arylsulfon yl-4,5-dihydro-3H-imidazol- 1-ium iodides (1 - 6), with two types of bifunc tional nucleophiles: ortho-substituted anilines and ethylenediamine was stu died. Their reactions with 1,2-phenylenediamine, 2-aminophenol, and 2-amino thiophenol resulted in exclusively one-carbon unit transfer products: 2-met hylbenzoxazole (7), 2-methylbenzimidole (8), and 2-methylbenzothiazole (9) respectively, which mimics the one-carbon unit transfer reaction of N(5), N (10)-methenyltetrahydrofolate coenzyme. The reaction of imidazolium (3, 4, and 6)with ethylenediamine exclusively produced the bis-adducts of two equi valents of imidazolium iodides with one equivalent of ethylenediamine: N-me thyl-N-(2-arylsulfonylamino) ethyl-N'- [2-(N'-2-arylsulfonylaminoethyl-N'-m ethyl)ethylideneamino]ethylacetamidine bishydroiodides (10 - 12) respective ly. These different behaviors were explained with addition reaction mechani sm.