Molecular structure and conformational analysis of two 2-oxo(thioxo)- 1,2,3,4-tetrahydropyrimidine-5-esters

Hamid Reza Memarian, Mahnaz Ranjbar, Hassan Sabzyan, Mohammad Hossein Habibi, Takayoshi Suzuki

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

X-ray crystal structure analysis and quantum chemical calculations based on density functional theory (DFT) were used for structural and electronic characterizations of two 1,2,3,4-tetrahydropyrimidine derivatives (THPMs), namely, ethyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5- carboxylate (1) and methyl 4-(4-bromophenyl)-1,6-dimethyl-2-oxo-1,2,3,4- tetrahydropyrimidine-5-carboxylate (2). The results of these studies revealed that the heterocyclic ring adopts a quasi-boat conformation, in which the 4-aryl group occupies the pseudo-axial position. The occurrence of the C 4-stereocenter in the heterocyclic ring causes the formation of both R- and S-enantiomers. X-ray diffraction technique indicates that both compounds exist as a racemic mixture in the crystal structure and the enantiomers are orientated to each other via hydrogen bonding between N3-H as donor and the C2=S or C2=O groups as acceptor species, in each layer under formation of an enantio-syndio packing. Most computational bond lengths and angles are well in agreement with experimental data, and support the pseudo-axial orientation of the C4-aryl substitution.

Original languageEnglish
Pages (from-to)196-201
Number of pages6
JournalJournal of Molecular Structure
Volume1048
DOIs
Publication statusPublished - Jan 1 2013

Keywords

  • 2-Oxo(thioxo)-1,2,3,4-
  • Conformational analysis
  • DFT study
  • Tetrahydropyrimidines
  • X-ray study

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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