SYNTHESIS AND CRYSTAL STRUCTURE ANALYSIS OF TWO THIAZOLO[3,2– a]PYRIMIDINE DERIVATIVES
H. Nagarajaiah1, M.I.A. Khazi2, A.Y. Khan2, N. Fathima1, I.A.M. Khazi2, N.S. Begum1
1Bangalore University, Bangalore-560001, India
2Karnatak University, Dharwad-580003, India
Keywords: thiazolo[3,2–a]pyrimidine derivative, crystal structure, C–H…O and C–H…Ï€ weak interactions
Abstract
Synthesis of 5R*–(3–methoxy–phenyl)–3,7–dimethyl–5H–thiazolo[3,2–a]pyrimidine–2,6–dicarboxylic acid diethyl ester (2a) and 3,7–dimethyl–5S*–thiophen–2–yl–5H–thiazolo[3,2–a]pyrimidine–2,6–dicarboxylic acid diethyl ester (2b) are achieved by the cyclocondensation of 3,4–dihydropyrimidine–2–thione derivative with a-haloester. Preliminary analysis was done spectroscopically by means of 1H NMR spectra, mass spectra and elemental analyses. Further the structures were confirmed by X-ray crystal structure analysis. The two molecules are not identical in configuration. In both the compounds the central pyrimidine ring adopts a conformation which is best described as an intermediate between a boat and screw boat form. The crystal structure is stabilized by intermolecular C–H…O and C–H…π weak interactions.
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