Diethyl 4-(2,4-dichloro­phen­yl)-2,6-dimethyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate

P Palakshi Reddy; V Vijayakumar; J Suresh; T Narasimhamurthy; P L Nilantha Lakshman

doi:10.1107/S1600536810001066

. 2010 Jan 16;66(Pt 2):o363. doi: 10.1107/S1600536810001066

Diethyl 4-(2,4-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate

P Palakshi Reddy ^a, V Vijayakumar ^a, J Suresh ^b, T Narasimhamurthy ^c, P L Nilantha Lakshman ^d,^*

PMCID: PMC2979797 PMID: 21579787

Abstract

In the title compound, C₁₉H₂₁Cl₂NO₄, the dihydropyridine ring adopts a flattened boat conformation. The dichlorophenyl ring is oriented almost perpendicular to the planar part of the dihydropyridine ring [dihedral angle = 89.1 (1)°]. An intramolecular C—H⋯O hydrogen bond is observed. In the crystal structure, molecules are linked into chains along the b axis by N—H⋯O hydrogen bonds

Related literature

The dihydropyridine hetrocyclic ring is a common feature of various bioactive compounds such as vasodilator, antiatherosclerotic, antitumor, geroprotective, heptaprotective and antidiabetic agents, see: Salehi & Guo (2004 ▶). For ring puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₉H₂₁Cl₂NO₄
M _r = 398.27
Monoclinic,
a = 15.928 (7) Å
b = 12.266 (6) Å
c = 10.042 (5) Å
β = 103.962 (7)°
V = 1903.8 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 293 K
0.19 × 0.16 × 0.12 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.933, T _max = 0.937
20317 measured reflections
4491 independent reflections
3230 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.061
wR(F ²) = 0.168
S = 1.04
4491 reflections
243 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.56 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810001066/ci5001sup1.cif

e-66-0o363-sup1.cif^{(18.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810001066/ci5001Isup2.hkl

e-66-0o363-Isup2.hkl^{(215.6KB, 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
N1—H1⋯O1ⁱ	0.85 (4)	2.46 (4)	3.298 (4)	169 (3)
C7—H7C⋯O2	0.96	2.14	2.764 (5)	122

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the use of the CCD facility at the Indian Institute of Science, Bangalore, set up under the IRHPA–DST programme.

supplementary crystallographic information

Comment

1,4-Dihydropyridines are identified as an important class of drugs for a longwhile. The dihydropyridine hetrocyclic ring is a common feature of various bioactive compounds such as vasodilator, antiatherosclerotic, antitumor, geroprotective, heptaprotective and antidiabetic agents (Salehi & Guo, 2004).

The molecular structure of the title compound, with the adopted atomic numbering scheme is shown in Fig. 1. The dihydropyridine ring adopts a flattened boat conformation, with atoms N1 and C4 slightly displaced out of the C2/C3/C5/C6 plane by 0.088 (4) and 0.188 (4) Å, respectively. The puckering parameters (Cremer & Pople, 1975) are: q₂ = 0.158 (3) Å, q₃ = -0.039 (3) Å and φ₂ = 3(1)°. The C—C and C—N bond distances of the pyridine ring agree well with expected values. The 2,4-dichlorophenyl ring at C4 is oriented at an angle of 89.1 (1)° with respect to the C2/C3/C5/C6 plane. This near perpendicular orientation of the chlorophenyl ring to the dihydropyridine ring can be ascribed to the greater steric hinderance with the two ethylcarboxylate groups at C3 and C5. Both ethylcarboxylate side chains adopt same orientation with respect to the dihydropyridine ring. An intramolecular C7—H7C···O2 hydrogen bond is observed.

In the crystal structure, the molecules are linked into chains along the b axis by N—H···O hydrogen bonds (Table 1).

Experimental

Diethyl 2,6-dimethyl-1,4-dihydro-4-2(2,6-dichlorophenyl)-3,5- pyridinedicarboxylate is prepared according to Hantzsch pyridine synthesis. 2,6-Dichlororobenzaldehyde (10 mmol, 1.76 g), ethylacetoacetate (20 mmol, 2.6 ml) and ammonium acetate (10 mmol, 0.8 g) were taken in a 1:2:1 mole ratio along with ethanol as a solvent in a flask and refluxed in steam-bath until the colour of the solution changed to reddish-orange (approximately an hour) and kept in ice cold condition to get a solid product. The product was extracted using diethyl ether and then excess solvent was distilled off. The purity of the crude product was checked through TLC and recrystallized using a acetone-benzene (3:1) solution. Single crystals of the title compound suitable for X-ray diffraction analysis were grown using a acetone-benzene (3:1) solution over a period of 2 d (yield = 68%, m.p. 413 K).