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Synthesis, NMR characterization and ab initio 6‐31G* study of 1‐aryl‐2,3‐dialkyl‐1,4,5,6‐tetrahydropyrimidinium salts
Author(s) -
Niemevz Fernando,
Link Natalia P.,
Perillo Isabel A.,
Orelli Liliana R.
Publication year - 2005
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570420410
Subject(s) - chemistry , protonation , carbon 13 nmr , amidine , aryl , ab initio , computational chemistry , nmr spectra database , proton nmr , alkylation , spectral line , medicinal chemistry , organic chemistry , catalysis , ion , alkyl , physics , astronomy
We describe the synthesis of a series of 1‐aryl‐2,3‐dialkyl‐1,4,5,6‐tetrahydropyrimidinium salts 1 , by alkylation of the corresponding 1,4,5,6‐tetrahydropyrimidines 2 . We analyze the changes in the 1 H and 13 C NMR spectra of compounds 2 induced by protonation and quaternization. The results of an ab initio theoretical study on amidine 2a , and the cations resulting from its protonation ( 2aH + ) and quaternization ( la + ) are presented. A qualitative correlation was found between 13 C NMR and theoretical data in the case of protonation. The influence of the substitution patterns in the 1 H and 13 C NMR spectra of compounds 1 is also discussed.