3-(2-Chloro­ethyl)-2-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidinium 2,4,6-trinitro­phenolate

Jerry P Jasinski; Ray J Butcher; Q N M Hakim Al-Arique; H S Yathirajan; B Narayana

doi:10.1107/S1600536809032693

. 2009 Aug 22;65(Pt 9):o2201–o2202. doi: 10.1107/S1600536809032693

3-(2-Chloroethyl)-2-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidinium 2,4,6-trinitrophenolate

Jerry P Jasinski ^a, Ray J Butcher ^b,^*, Q N M Hakim Al-Arique ^c, H S Yathirajan ^c, B Narayana ^d

PMCID: PMC2970075 PMID: 21577604

Abstract

In the cation of the title salt, C₁₁H₁₂ClN₂O⁺·C₆H₂N₃O₇ ⁻, the chloroethyl side chain is in a syn conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle of 78.9 (6)° between the plane of the chloroethyl chain and the pyrimidine ring. The dihedral angle between the fused rings is 4.3 (3)°. In the picrate anion, the benzene mean plane makes dihedral angles of 26.7 (1), 33.6 (2) and 5.3 (6)° with the two o-NO₂ groups and the p-NO₂ group, respectively. Extensive hydrogen-bond interactions occur between the cation–anion pair which help to establish the crystal packing. A three-center O⋯(H,H)—(N,C) acceptor hydrogen bond is observed between the phenolate O atom of the picrate anion and the amine and methyl groups of the cation. An N—H⋯(O,O) bifurcated hydrogen bond is observed between the amine group and two O atoms from the phenolate and o-NO₂ groups.

Related literature

For related structures, see: Blaton et al. (1995 ▶); Chen & He (2006 ▶); Peeters et al. (1993 ▶). For general background, see: Baraldi et al. (2002 ▶); Gabbert & Giannini (1997 ▶); Jasinski et al. (2009 ▶); White et al. (2004 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶) and for the program Mogul, see: Bruno et al. (2004 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₁H₁₂ClN₂O⁺·C₆H₂N₃O₇ ⁻
M _r = 451.78
Monoclinic,
a = 7.2718 (5) Å
b = 12.8159 (9) Å
c = 19.940 (3) Å
β = 97.642 (9)°
V = 1841.8 (3) Å³
Z = 4
Cu Kα radiation
μ = 2.41 mm⁻¹
T = 110 K
0.44 × 0.37 × 0.23 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Cu) detector
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 ▶) T _min = 0.309, T _max = 0.575
6948 measured reflections
3616 independent reflections
3198 reflections with I > 2σ(I)
R _int = 0.017

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.097
S = 1.03
3616 reflections
281 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: CrysAlis Pro (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2007 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809032693/is2446sup1.cif

e-65-o2201-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809032693/is2446Isup2.hkl

e-65-o2201-Isup2.hkl^{(177.3KB, 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
N4A—H4AA⋯O1B	0.88	1.82	2.6811 (16)	167
N4A—H4AA⋯O62B	0.88	2.58	2.8632 (17)	100
C5B—H5BA⋯Cl1Aⁱ	0.95	2.79	3.6112 (16)	146
C7A—H7AA⋯O1Aⁱⁱ	0.95	2.57	3.2446 (19)	128
C12A—H12C⋯O1B	0.98	2.41	3.2477 (19)	144
C9A—H9AA⋯O61Bⁱⁱⁱ	0.95	2.61	3.2734 (19)	127
C12A—H12A⋯O21B^iv	0.98	2.62	3.340 (2)	131
C10A—H10B⋯O62B^v	0.99	2.54	3.494 (2)	161
C11A—H11A⋯O22B^vi	0.99	2.52	3.385 (2)	146
C11A—H11B⋯O42B^vii	0.99	2.56	3.431 (2)	147

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

Acknowledgments

QNMHA thanks the University of Mysore for use of its research facilities. RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.

supplementary crystallographic information

Comment

We have recently reported the crystal structure of 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (Jasinski et al., 2009) which is an intermediate in the synthesis of risperidone, and is a potent antipsychotic agent, especially useful for treating schizophrenia (Gabbert & Giannini, 1997). The present paper reports the interaction of 3-(2-chloroethyl)-2-methyl-4H-pyrido [1,2-a]pyrimidin-4-one as an electron donor with picric acid as electron acceptor which resulted in the formation of a charge transfer complex of title compound, (I), C₁₇H₁₄ClN₅O₈.

The title compound, C₁₁H₁₂ClN₂O⁺.C₆H₂N₃O₇^-, a picrate salt of 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidinium-4-one, crystallizes with one independent cation-anion pair in the asymmetric unit (Fig. 1). In the cation, the chloroethyl side chain is in a syn conformation [-sc, C1A—C2A—C10A—C11A = -78.29 (16)°], nearly orthogonal to the pyrimidine ring, with a dihedral angle of 78.9 (6)° between the chloroethyl side chain and the pyrimidine ring. The fused pyrimidine-pyridine ring is separated by 4.3 (3)°. In the picrate anion, the benzene ring adopts dihedral angles of 26.7 (1), 33.6 (2) and 5.3 (6)° with the mean planes of two o-NO₂ and a p-NO₂ group, respectively. Extensive hydrogen bond interactions occur between the cation-anion pair which help to establish crystal packing (Fig. 2). This includes a strong N4A—H4AA···O1B hydrogen bond and a collection of several weak C—H···O interactions within several sites between the cations and anions in the unit cell (Table 1). A three-center O···(H,H)-(N,C) acceptor hydrogen bond is observed between the phenolate oxygen atom (O1B) of the picrate anion and the amine (H4AA) and methyl group (H12C) hydrogen atoms of the pyrimidine group in the cation. A bifurcated (three-center) N—H···(O,O) hydrogen bond is observed between the amine hydrogen atom (H4AA) in the pyrimidine group and oxygen atoms from the phenolate (O1B) and o-NO₂ (O62B) groups. Included in this bond is a weak N4A—H4AA···O62B interaction (Table 1). Bond lengths and angles in both the cation and anion can be regarded as normal (Cambridge Structural Database, Version 5.30, February, 2009; Allen, 2002, Mogul, Version 1.1.3; Bruno et al., 2004) The collective effects of both strong and weak intemolecular hydrogen bonds influence crystal packing in the title compound, C₁₁H₁₂ClN₂O⁺.C₆H₂N₃O₇^-, (I).

Experimental

The title compound was synthesized by adding a saturated solution of picric acid (0.92 g, 2 mmol) in methanol to a solution of 3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (0.45 g, 2 mmol) in 10 ml of methanol. A yellow color developed and the resulting solution was stirred well with the formation of yellow precipitate which was filtered off, washed several times with diethyl ether and then dried over CaCl₂ (yield 64.5%). X-ray quality crystals were grown from acetone solution. The melting range was found to be 415–418 K.