1-(4-Chloro­phen­yl)-4,4,6-trimethyl-3,4-dihydro­pyrimidine-2(1H)-thione

Aamer Saeed; Michael Bolte

doi:10.1107/S1600536810001777

. 2010 Jan 23;66(Pt 2):o440. doi: 10.1107/S1600536810001777

1-(4-Chlorophenyl)-4,4,6-trimethyl-3,4-dihydropyrimidine-2(1H)-thione

Aamer Saeed ^a,^*, Michael Bolte ^b

PMCID: PMC2979773 PMID: 21579855

Abstract

The dihydropyrimidine ring of the title compound, C₁₃H₁₅ClN₂S, adopts an envelope conformation with five almost coplanar atoms (r.m.s. deviation = 0.054 Å) and the C atom bearing the two methyl substituents deviating from this plane by 0.441 (2) Å. The best plane through the five almost coplanar atoms forms a dihedral angle of 89.56 (5)° with the benzene ring. The crystal packing is characterized by centrosymmetric dimers connected by pairs of N—H⋯S hydrogen bonds.

Related literature

For details of the biological activity of pyrimidine-2-thiones, see: Alam et al. (2005 ▶); Sriram et al. (2006 ▶); Leite et al. (2006 ▶); Kappe (2000 ▶); Rovnyak et al. (1995 ▶); Swamy et al. (2005 ▶). For a related structure, see: Yamin et al. (2005 ▶).

Experimental

Crystal data

C₁₃H₁₅ClN₂S
M _r = 266.78
Monoclinic,
a = 20.6710 (18) Å
b = 10.8343 (10) Å
c = 14.8619 (13) Å
β = 126.026 (5)°
V = 2691.9 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.42 mm⁻¹
T = 173 K
0.37 × 0.29 × 0.26 mm

Data collection

Stoe IPDS II two-circle diffractometer
Absorption correction: multi-scan (MULABS; Spek, 2009 ▶; Blessing, 1995 ▶) T _min = 0.861, T _max = 0.899
7624 measured reflections
2512 independent reflections
2134 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.093
S = 1.02
2512 reflections
161 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810001777/zq2028sup1.cif

e-66-0o440-sup1.cif^{(17.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810001777/zq2028Isup2.hkl

e-66-0o440-Isup2.hkl^{(123.5KB, hkl)}

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
N3—H1⋯S1ⁱ	0.83 (2)	2.59 (2)	3.4054 (16)	169.1 (17)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors gratefully acknowledge a research grant from the Higher Education Commission of Pakistan under project No. 20-Miscel/R&D/00/3834.

supplementary crystallographic information

Comment

The title compound belongs to a novel and rare class of dihydropyrimidine-2-thiones. Their synthesis has been attracting widespread attention due to diverse pharmacological activities such as antibacterial (Alam et al., 2005), antitumour (Swamy et al., 2005), antioxidative (Sriram et al., 2006), analgesic and anti-inflammatory properties (Leite et al., 2006; Kappe, 2000). In addition, these compounds act as antihypertensive agents as well as calcium channel blockers and neuropeptide Y antagonists (Rovnyak et al., 1995). The formation of the closely related 4,4,6-trimethyl-1-phenyl-3,4-dihydropyrimidine-2(1H)-thione as a side product during the reaction of cinnamoyl isothiocyanate and aniline to afford the corresponding thiourea derivative has been reported (Yamin et al., 2005) The title compound was prepared by the reaction of 4-chloroaniline with 4-methylpent-3-en-2-one in presence of potassium thiocyanate in acetone.

The dihydropyrimidine ring of the title compound adopts an envelope conformation with five almost coplanar atoms (r.m.s. deviation 0.054 Å) and the carbon atom bearing the two methyl substituents deviating from this plane by 0.441 (2) Å. The best plane through the six ring atoms forms a dihedral angle of 89.42 (5)° with the phenyl ring. The crystal packing is characterized by centrosymmetric dimers connected by N—H···S hydrogen bonds.

Experimental

Potassium thiocyanate (5.4 mmol) was added to a stirred mixture of 4-methylpent-3-en-2-one (5.4 mmol), 4-chloroaniline (5.4 mmol) in dry acetone. The reaction mixture was refluxed for 3 hours. On completion of the reaction, the reaction mixture was cooled to room temperature and poured into ice-water. The precipitated compound was recrystallized from methanol to afford the title dihydropyrimidine-2-thione (62%). Recrystallization from methanol afforded the title compound as colourless crystals: Anal. calcd. for C₁₃H₁₅N₂S: C, 58.53; H, 5.67; N, 10.50; S, 12.02%; found: C, 58.49; H, 5.72; N, 10.61; S, 12.14%;%.