Highly Selective Alkylation of 5‐Amino‐1‐methyl‐1 H ‐1,2,4‐triazole with 1‐(1‐Chloroalkyl)pyridinium Chlorides under Formation of Novel Geminal Bis(heteroarylium) Salts: A Combined Experimental/MO‐Theoretical Study

1‐[(5‐Amino‐1‐methyl‐1 H ‐1,2,4‐triazol‐4‐ylium)(alkyl/aryl)‐methyl]pyridinium dichlorides 3a–h [geminal bis(heteroarylium) salts] were synthesized in high yield from 5‐amino‐1‐methyl‐1 H ‐1,2,4‐triazole ( 6a ) and the 1‐[(alkyl/aryl)chloromethyl]pyridinium chlorides 1a–h under mild, neutral conditions. Analogous reactions of 1a and 1d with the isomeric 3‐amino‐1‐methyl‐1 H ‐1,2,4‐triazole ( 6b ), carried out to support the spectroscopic analysis of the alkylation products 3a–h , likewise show exclusive alkylation at the N‐4 atom of the 1 H ‐1,2,4‐triazole ring with formation of the isomeric 1‐[(3‐amino‐1‐methyl‐1 H ‐1,2,4‐triazol‐4‐ylium)arylmethyl]pyridinium dichlorides 4a and 4d , respectively. Semiempirical MO and ab initio methods have been applied to predict the relative energies of isomers of 6 , the activation barriers of the reaction of electrophiles with 6 , and the relative energies of some product salts.