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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
Author(s) -
Anders Ernst,
Wermann Kurt,
Wiedel Bernd,
Eynde JeanJacques Vanden
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970417
Subject(s) - chemistry , pyridinium , geminal , alkylation , medicinal chemistry , electrophile , alkyl , aryl , yield (engineering) , organic chemistry , catalysis , materials science , metallurgy
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.