Ethyl 7-methyl-3-oxo-5-phenyl-2-(2,4,6-trimeth­oxy­benzyl­idene)-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate

Noor Afshan Banu; V Bheema Raju

doi:10.1107/S1600536812012354

. 2012 Mar 28;68(Pt 4):o1213. doi: 10.1107/S1600536812012354

Ethyl 7-methyl-3-oxo-5-phenyl-2-(2,4,6-trimethoxybenzylidene)-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate

Noor Afshan Banu ^a, V Bheema Raju ^b,^*

PMCID: PMC3344148 PMID: 22606151

Abstract

In the title compound, C₂₆H₂₆N₂O₆S, the benzene ring is positioned axially to the thiazolopyrimidine ring and bisects it with a dihedral angle of 80.94 (7)°. The pyrimidine ring adopts a flattened boat conformation. In the crystal, pairs of bifurcated C—H⋯O hydrogen bonds link the molecules into chains along the c axis.

Related literature

For the pharmacological activity of pyrimidine derivatives, see: Alam et al. (2010 ▶). For a related crystal structure, see: Chen et al. (2012 ▶).

Experimental

Crystal data

C₂₆H₂₆N₂O₆S
M _r = 494.55
Monoclinic,
a = 7.5363 (19) Å
b = 18.178 (5) Å
c = 16.973 (4) Å
β = 94.465 (5)°
V = 2318.1 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.19 mm⁻¹
T = 296 K
0.18 × 0.16 × 0.16 mm

Data collection

Bruker SMART APEX CCD detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.967, T _max = 0.971
13918 measured reflections
5055 independent reflections
3500 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.058
wR(F ²) = 0.168
S = 1.07
5055 reflections
321 parameters
H-atom parameters constrained
Δρ_max = 0.59 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT-Plus (Bruker, 1998 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and CAMERON (Watkin et al., 1996 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812012354/pv2518sup1.cif

e-68-o1213-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812012354/pv2518Isup2.hkl

e-68-o1213-Isup2.hkl^{(242.6KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812012354/pv2518Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C24—H24C⋯O5ⁱ	0.96	2.63	3.537 (3)	158
C25—H25A⋯O5ⁱ	0.96	2.57	3.319 (3)	135

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Symmetry code: (i) Inline graphic .

Acknowledgments

NAB is grateful to KNS Institute of Technology for the encouragement and Rayalaseema University, Kurnool, India, for the data collection facility.

supplementary crystallographic information

Comment

Pyrimidine derivatives are of interest because of their pharmacological properties (Alam et al., 2010). In the title compound (Fig. 1), the central pyrimidine ring with a chiral C5 atom is significantly puckered and adopts conformation as seen earlier (Chen et al., 2012). The atom C5 deviates from the mean plane formed by the atoms N2/C9/N1/C6/C7 by 0.224 (2) Å, indicating that the conformation of the ring is that of a flattened boat. In the molecule, the fused thiazolopyrimidine ring makes a dihedral angle of 80.94 (7)° with the benzene ring (C11–C16). In the crystal, pairs of C—H···O hydrogen bonds are bifurcated linking the molecules into chains along c-axis (Fig. 2 and Table 1).

Experimental

A mixture of 5-phenyl-6-methyl-2-thioxo-1,2,3,4-tetrahydro -pyrimidine-5-carboxylic acid ethyl ester (0.01 mol, 2.76 g), chloroaceticacid (0.01 mol, 0.94 g), 2,4,6-trimethoxy benzaldehyde (0.01 mol, 1.96 g) and sodium acetate (1.5 g) in a mixture of glacial acetic acid and acetic anhydride (25 ml, 1:1) was refluxed for 8–10 h. The reaction mixture was concentrated and the solid thus obtained was filtered and recrystallized from ethyl acetate to get the title compound (78% yield, mp 427–428 K). The compound was recrystallized by slow evaporation of an ethyl acetate-ethanol (3:2) solution, yielding pale yellow single crystals suitable for X-ray diffraction studies.