organic compounds
2-Methyl-3-(3-methylisoxazol-5-yl)-4-oxo-4H-pyrido[1,2-a]pyrimidin-1-ium chloride
aLaboratoire de Chimie Organique Hétérocyclique, URAC 21, Pôle de Compétence Pharmacochimie, Av Ibn Battouta, BP 1014, Faculté des Sciences, Université Mohammed V, Rabat, Morocco, and bDepartment of Chemistry, Tulane University, New Orleans, LA 70118, USA
*Correspondence e-mail: lahmidi_sanae@yahoo.fr
In the title molecular salt, C13H12N3O2+·Cl−, the oxazolyl ring is disordered over two orientations in a 0.536 (15):0.464 (15) ratio, both of which approximate to envelopes with the N atom as the flap in each case. The cation and anion are linked by a charge-assisted N—H⋯Cl hydrogen bond. In the extended structure, C—H⋯N, C—H⋯O and C—H⋯Cl interactions link the components into a three-dimensional network.
Keywords: crystal structure; hydrogen bond; pyridopyrimidinium chloride.
CCDC reference: 1521971
Structure description
Pyridopyrimidine compounds have found use as antimalarial agents (Mane et al., 2014), anti-allergic agents (Awouters et al., 1986) and urease inhibitors (Rauf et al., 2012). The isoxazole nucleus is known to exhibit anticancer (Han et al., 2002), anti-HIV (Deng et al., 2006) and fungicide (Raffa et al., 1999) activities. The present work reporting the synthesis and structure of the title molecular salt (Fig. 1) is a continuation of our work on pyridopyrimidine derivatives (Djerrari et al., 2002).
The bicyclic core of the cation is slightly folded along the C5—N1 axis by 1.07 (14)°. In the oxazolyl substituent, the oxygen and nitrogen atoms and the C—CH3 grouping are disordered over two sets of sites, which represent the two possible envelope conformations of the five-membered ring (flap atom = N). The cation and anion are strongly associated through the N2—H2A⋯Cl1 hydrogen bond (Table 1 and Fig. 1). In the extended structure, the ion pairs are arranged in rows running along the a-axis direction with weak, bifurcated C13A—H13A⋯O2Ai and C13A—H13A⋯N3Ai [symmetry code: (i) − x, + y, − z] hydrogen bonds (Table 1 and Fig. 2) as well as weak C—H⋯Cl interactions.
Synthesis and crystallization
A mixture of 1-(2-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidin-3-yl)butane-1,3-dione (0.7 g, 2.86 mmol) and of hydroxylamine hydrochloride (0.4 g, 5.75 mmol) in methanol (30 ml) was heated at reflux for 4 h. The completion of the reaction was confirmed by TLC. The solid obtained upon cooling the mixture was recrystallized from ethanol solution to afford orange blocks (yield: 76%. m.p.: 465–467 K).
Refinement
Crystal data, data collection and structure . In the pendant oxazolyl substituent, all atoms except C10 and C11 are disordered over two sets of sites in a 0.536 (15):0.464 (15) ratio. The two components of the disorder were refined with restraints that their geometries be comparable.
details are summarized in Table 2
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Structural data
CCDC reference: 1521971
https://doi.org/10.1107/S2414314616019787/hb4105sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616019787/hb4105Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314616019787/hb4105Isup3.cdx
Supporting information file. DOI: https://doi.org/10.1107/S2414314616019787/hb4105Isup4.cml
Data collection: APEX3 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: CELL_NOW (Sheldrick, 2008a) and SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg & Putz, 2012); software used to prepare material for publication: SHELXTL (Sheldrick, 2008b).C13H12N3O2+·Cl− | F(000) = 576 |
Mr = 277.70 | Dx = 1.439 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 6.2796 (12) Å | Cell parameters from 5128 reflections |
b = 9.6912 (18) Å | θ = 2.3–25.9° |
c = 21.152 (4) Å | µ = 0.30 mm−1 |
β = 95.294 (3)° | T = 298 K |
V = 1281.8 (4) Å3 | Block, orange |
Z = 4 | 0.32 × 0.20 × 0.19 mm |
Bruker SMART APEX CCD diffractometer | 6596 independent reflections |
Radiation source: fine-focus sealed tube | 4582 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.068 |
Detector resolution: 8.3333 pixels mm-1 | θmax = 28.8°, θmin = 1.9° |
φ and ω scans | h = −8→8 |
Absorption correction: multi-scan (TWINABS; Sheldrick, 2009) | k = −13→13 |
Tmin = 0.75, Tmax = 0.94 | l = −28→28 |
28190 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.064 | Hydrogen site location: mixed |
wR(F2) = 0.192 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0802P)2 + 0.5444P] where P = (Fo2 + 2Fc2)/3 |
6596 reflections | (Δ/σ)max = 0.001 |
222 parameters | Δρmax = 0.36 e Å−3 |
53 restraints | Δρmin = −0.33 e Å−3 |
Experimental. The diffraction data were obtained from 3 sets of 400 frames, each of width 0.5° in ω, colllected at φ = 0.00, 90.00 and 180.00° and 2 sets of 800 frames, each of width 0.45° in φ, collected at ω = –30.00 and 210.00°. The scan time was 20 sec/frame. Analysis of 1600 reflections having I/σ(I) > 12 and chosen from the full data set with CELL_NOW (Sheldrick, 2008a) showed the crystal to belong to the monoclinic system and to be twinned by a 180° rotation about the c* axis. The raw data were processed using the multi- component version of SAINT under control of the two-component orientation file generated by CELL_NOW. |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. The methyl oxazole moiety is disordered over two partially resolved sites with the disorder mainly involving alternate conformations of the heteroatom prtion of the ring. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.6819 (4) | 0.8510 (2) | 0.65445 (14) | 0.0747 (8) | |
N1 | 0.9648 (4) | 0.7726 (2) | 0.60427 (12) | 0.0472 (6) | |
H1A | 1.092 (5) | 0.470 (4) | 0.5794 (15) | 0.048 (8)* | |
N2 | 1.0175 (4) | 0.5368 (3) | 0.59451 (11) | 0.0460 (6) | |
O2A | 0.497 (2) | 0.4524 (5) | 0.7017 (5) | 0.067 (2) | 0.536 (15) |
N3A | 0.374 (2) | 0.4582 (16) | 0.7600 (5) | 0.068 (3) | 0.536 (15) |
O2B | 0.549 (2) | 0.4604 (7) | 0.7216 (6) | 0.067 (2) | 0.464 (15) |
N3B | 0.320 (2) | 0.4573 (19) | 0.7389 (7) | 0.068 (3) | 0.464 (15) |
C1 | 1.0220 (6) | 0.9076 (3) | 0.59290 (16) | 0.0571 (8) | |
H1 | 0.933 (6) | 0.971 (4) | 0.6091 (17) | 0.063 (10)* | |
C2 | 1.1882 (6) | 0.9357 (4) | 0.55943 (17) | 0.0614 (8) | |
H2 | 1.227 (5) | 1.032 (4) | 0.5534 (15) | 0.058 (9)* | |
C3 | 1.3048 (5) | 0.8268 (4) | 0.53573 (16) | 0.0578 (8) | |
H3 | 1.424 (6) | 0.848 (4) | 0.5106 (16) | 0.060 (9)* | |
C4 | 1.2516 (5) | 0.6939 (3) | 0.54654 (14) | 0.0505 (7) | |
H4 | 1.327 (5) | 0.616 (3) | 0.5311 (14) | 0.046 (8)* | |
C5 | 1.0770 (5) | 0.6671 (3) | 0.58186 (13) | 0.0448 (6) | |
C7 | 0.7321 (5) | 0.6085 (3) | 0.65240 (13) | 0.0450 (6) | |
C6 | 0.8520 (5) | 0.5045 (3) | 0.62902 (13) | 0.0445 (6) | |
C9 | 0.8178 (6) | 0.3526 (3) | 0.6367 (2) | 0.0566 (8) | |
H9A | 0.841 (7) | 0.328 (4) | 0.678 (2) | 0.090 (14)* | |
H9B | 0.685 (7) | 0.327 (4) | 0.6228 (19) | 0.075 (12)* | |
H9C | 0.921 (7) | 0.298 (5) | 0.614 (2) | 0.089 (13)* | |
C8 | 0.7780 (5) | 0.7504 (3) | 0.63969 (15) | 0.0510 (7) | |
C10 | 0.5567 (5) | 0.5859 (3) | 0.69230 (13) | 0.0476 (7) | |
C11 | 0.4164 (5) | 0.6703 (3) | 0.71767 (15) | 0.0510 (7) | |
H11 | 0.400 (6) | 0.762 (4) | 0.7120 (16) | 0.065 (11)* | |
C12A | 0.279 (3) | 0.5827 (14) | 0.7485 (9) | 0.046 (3) | 0.536 (15) |
C13A | 0.117 (4) | 0.630 (4) | 0.7921 (13) | 0.059 (2) | 0.536 (15) |
H13A | 0.0628 | 0.7190 | 0.7787 | 0.089* | 0.536 (15) |
H13B | 0.0014 | 0.5650 | 0.7908 | 0.089* | 0.536 (15) |
H13C | 0.1839 | 0.6364 | 0.8347 | 0.089* | 0.536 (15) |
C12B | 0.306 (4) | 0.5894 (16) | 0.7596 (11) | 0.046 (3) | 0.464 (15) |
C13B | 0.110 (5) | 0.617 (5) | 0.7933 (15) | 0.059 (2) | 0.464 (15) |
H13D | 0.1091 | 0.7114 | 0.8067 | 0.089* | 0.464 (15) |
H13E | −0.0157 | 0.5989 | 0.7649 | 0.089* | 0.464 (15) |
H13F | 0.1097 | 0.5576 | 0.8297 | 0.089* | 0.464 (15) |
Cl1 | 1.28278 (13) | 0.31411 (8) | 0.53955 (4) | 0.0574 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0733 (16) | 0.0429 (12) | 0.115 (2) | 0.0045 (11) | 0.0483 (15) | −0.0048 (13) |
N1 | 0.0485 (13) | 0.0420 (12) | 0.0527 (13) | −0.0001 (10) | 0.0139 (11) | −0.0023 (10) |
N2 | 0.0463 (13) | 0.0418 (12) | 0.0514 (13) | 0.0045 (10) | 0.0130 (11) | −0.0006 (10) |
O2A | 0.088 (5) | 0.0476 (14) | 0.073 (5) | −0.0073 (16) | 0.045 (4) | −0.008 (2) |
N3A | 0.090 (6) | 0.0550 (18) | 0.065 (6) | −0.004 (4) | 0.042 (5) | −0.002 (5) |
O2B | 0.088 (5) | 0.0476 (14) | 0.073 (5) | −0.0073 (16) | 0.045 (4) | −0.008 (2) |
N3B | 0.090 (6) | 0.0550 (18) | 0.065 (6) | −0.004 (4) | 0.042 (5) | −0.002 (5) |
C1 | 0.063 (2) | 0.0418 (16) | 0.069 (2) | −0.0008 (14) | 0.0182 (16) | −0.0025 (14) |
C2 | 0.067 (2) | 0.0487 (18) | 0.071 (2) | −0.0085 (15) | 0.0187 (17) | 0.0023 (15) |
C3 | 0.0541 (18) | 0.0594 (19) | 0.0626 (19) | −0.0049 (15) | 0.0190 (15) | 0.0000 (15) |
C4 | 0.0468 (16) | 0.0529 (17) | 0.0538 (16) | 0.0014 (13) | 0.0149 (13) | −0.0018 (13) |
C5 | 0.0451 (14) | 0.0425 (14) | 0.0475 (15) | 0.0017 (11) | 0.0076 (12) | −0.0004 (11) |
C7 | 0.0470 (15) | 0.0427 (14) | 0.0465 (14) | 0.0010 (12) | 0.0111 (12) | −0.0025 (11) |
C6 | 0.0449 (14) | 0.0424 (14) | 0.0466 (14) | 0.0020 (11) | 0.0065 (12) | 0.0016 (11) |
C9 | 0.058 (2) | 0.0432 (16) | 0.071 (2) | 0.0025 (15) | 0.0213 (18) | 0.0033 (15) |
C8 | 0.0477 (16) | 0.0471 (16) | 0.0603 (17) | 0.0009 (13) | 0.0168 (14) | −0.0031 (13) |
C10 | 0.0522 (16) | 0.0436 (15) | 0.0480 (15) | −0.0021 (12) | 0.0106 (12) | −0.0031 (12) |
C11 | 0.0510 (17) | 0.0476 (17) | 0.0565 (17) | 0.0006 (13) | 0.0172 (13) | −0.0001 (13) |
C12A | 0.049 (4) | 0.0526 (19) | 0.037 (6) | −0.008 (2) | 0.006 (5) | −0.010 (3) |
C13A | 0.064 (2) | 0.055 (6) | 0.063 (2) | −0.007 (3) | 0.0261 (17) | −0.004 (2) |
C12B | 0.049 (4) | 0.0526 (19) | 0.037 (6) | −0.008 (2) | 0.006 (5) | −0.010 (3) |
C13B | 0.064 (2) | 0.055 (6) | 0.063 (2) | −0.007 (3) | 0.0261 (17) | −0.004 (2) |
Cl1 | 0.0549 (4) | 0.0508 (4) | 0.0684 (5) | 0.0076 (3) | 0.0152 (4) | −0.0032 (3) |
O1—C8 | 1.203 (4) | C4—H4 | 0.96 (3) |
N1—C5 | 1.352 (4) | C7—C6 | 1.377 (4) |
N1—C1 | 1.383 (4) | C7—C8 | 1.436 (4) |
N1—C8 | 1.465 (4) | C7—C10 | 1.465 (4) |
N2—C5 | 1.351 (4) | C6—C9 | 1.498 (4) |
N2—C6 | 1.360 (4) | C9—H9C | 0.99 (4) |
N2—H1A | 0.88 (4) | C9—H9B | 0.89 (4) |
O2A—C10 | 1.368 (5) | C9—H9A | 0.90 (5) |
O2A—N3A | 1.513 (6) | C10—C11 | 1.349 (4) |
N3A—C12A | 1.359 (10) | C11—C12B | 1.412 (5) |
O2B—C10 | 1.368 (5) | C11—C12A | 1.412 (5) |
O2B—N3B | 1.515 (7) | C11—H11 | 0.90 (4) |
N3B—C12B | 1.358 (10) | C12A—C13A | 1.506 (7) |
C1—C2 | 1.342 (5) | C13A—H13A | 0.9600 |
C1—H1 | 0.92 (4) | C13A—H13B | 0.9600 |
C2—C3 | 1.403 (5) | C13A—H13C | 0.9600 |
C2—H2 | 0.97 (4) | C12B—C13B | 1.506 (7) |
C3—C4 | 1.355 (5) | C13B—H13D | 0.9600 |
C3—H3 | 0.98 (4) | C13B—H13E | 0.9600 |
C4—C5 | 1.407 (4) | C13B—H13F | 0.9600 |
C5—N1—C1 | 120.1 (3) | C6—C9—H9A | 112 (3) |
C5—N1—C8 | 122.4 (2) | H9C—C9—H9A | 105 (4) |
C1—N1—C8 | 117.5 (2) | H9B—C9—H9A | 109 (3) |
C5—N2—C6 | 124.1 (3) | O1—C8—C7 | 127.9 (3) |
C5—N2—H1A | 117 (2) | O1—C8—N1 | 117.3 (3) |
C6—N2—H1A | 119 (2) | C7—C8—N1 | 114.9 (2) |
C10—O2A—N3A | 104.6 (9) | C11—C10—O2A | 108.5 (6) |
C12A—N3A—O2A | 97.7 (12) | C11—C10—O2B | 107.8 (6) |
C10—O2B—N3B | 101.7 (10) | C11—C10—C7 | 133.8 (3) |
C12B—N3B—O2B | 98.5 (15) | O2A—C10—C7 | 117.2 (5) |
C2—C1—N1 | 120.8 (3) | O2B—C10—C7 | 117.1 (6) |
C2—C1—H1 | 126 (2) | C10—C11—C12B | 106.8 (9) |
N1—C1—H1 | 113 (2) | C10—C11—C12A | 105.6 (7) |
C1—C2—C3 | 119.5 (3) | C10—C11—H11 | 128 (2) |
C1—C2—H2 | 119 (2) | C12B—C11—H11 | 125 (2) |
C3—C2—H2 | 122 (2) | C12A—C11—H11 | 126 (2) |
C4—C3—C2 | 120.7 (3) | N3A—C12A—C11 | 109.9 (13) |
C4—C3—H3 | 120 (2) | N3A—C12A—C13A | 118.1 (16) |
C2—C3—H3 | 119 (2) | C11—C12A—C13A | 125.1 (19) |
C3—C4—C5 | 118.8 (3) | C12A—C13A—H13A | 109.5 |
C3—C4—H4 | 123.6 (19) | C12A—C13A—H13B | 109.5 |
C5—C4—H4 | 117.6 (19) | H13A—C13A—H13B | 109.5 |
N2—C5—N1 | 118.3 (3) | C12A—C13A—H13C | 109.5 |
N2—C5—C4 | 121.4 (3) | H13A—C13A—H13C | 109.5 |
N1—C5—C4 | 120.2 (3) | H13B—C13A—H13C | 109.5 |
C6—C7—C8 | 120.5 (3) | N3B—C12B—C11 | 105.8 (13) |
C6—C7—C10 | 124.3 (3) | N3B—C12B—C13B | 113 (2) |
C8—C7—C10 | 115.2 (2) | C11—C12B—C13B | 132 (2) |
N2—C6—C7 | 119.6 (3) | C12B—C13B—H13D | 109.5 |
N2—C6—C9 | 114.1 (3) | C12B—C13B—H13E | 109.5 |
C7—C6—C9 | 126.3 (3) | H13D—C13B—H13E | 109.5 |
C6—C9—H9C | 111 (3) | C12B—C13B—H13F | 109.5 |
C6—C9—H9B | 112 (3) | H13D—C13B—H13F | 109.5 |
H9C—C9—H9B | 108 (4) | H13E—C13B—H13F | 109.5 |
C10—O2A—N3A—C12A | 35.8 (19) | C1—N1—C8—O1 | 2.8 (5) |
C10—O2B—N3B—C12B | −42.4 (18) | C5—N1—C8—C7 | 4.0 (4) |
C5—N1—C1—C2 | 0.3 (5) | C1—N1—C8—C7 | −177.4 (3) |
C8—N1—C1—C2 | −178.4 (3) | N3A—O2A—C10—C11 | −25.9 (13) |
N1—C1—C2—C3 | 0.0 (6) | N3A—O2A—C10—C7 | 161.2 (9) |
C1—C2—C3—C4 | −0.2 (6) | N3B—O2B—C10—C11 | 29.1 (12) |
C2—C3—C4—C5 | 0.1 (5) | N3B—O2B—C10—C7 | −162.2 (8) |
C6—N2—C5—N1 | −0.6 (4) | C6—C7—C10—C11 | −177.0 (3) |
C6—N2—C5—C4 | 179.2 (3) | C8—C7—C10—C11 | 4.6 (5) |
C1—N1—C5—N2 | 179.3 (3) | C6—C7—C10—O2A | −6.3 (8) |
C8—N1—C5—N2 | −2.1 (4) | C8—C7—C10—O2A | 175.2 (7) |
C1—N1—C5—C4 | −0.4 (4) | C6—C7—C10—O2B | 18.1 (8) |
C8—N1—C5—C4 | 178.2 (3) | C8—C7—C10—O2B | −160.4 (7) |
C3—C4—C5—N2 | −179.5 (3) | O2B—C10—C11—C12B | −5.3 (14) |
C3—C4—C5—N1 | 0.2 (5) | C7—C10—C11—C12B | −171.3 (13) |
C5—N2—C6—C7 | 1.1 (4) | O2A—C10—C11—C12A | 5.4 (12) |
C5—N2—C6—C9 | −179.8 (3) | C7—C10—C11—C12A | 176.6 (11) |
C8—C7—C6—N2 | 1.1 (4) | O2A—N3A—C12A—C11 | −33 (2) |
C10—C7—C6—N2 | −177.3 (3) | O2A—N3A—C12A—C13A | 174 (2) |
C8—C7—C6—C9 | −177.9 (3) | C10—C11—C12A—N3A | 20.2 (19) |
C10—C7—C6—C9 | 3.8 (5) | C10—C11—C12A—C13A | 170 (2) |
C6—C7—C8—O1 | 176.4 (4) | O2B—N3B—C12B—C11 | 40 (2) |
C10—C7—C8—O1 | −5.1 (5) | O2B—N3B—C12B—C13B | −169 (2) |
C6—C7—C8—N1 | −3.4 (4) | C10—C11—C12B—N3B | −24 (2) |
C10—C7—C8—N1 | 175.1 (3) | C10—C11—C12B—C13B | −168 (3) |
C5—N1—C8—O1 | −175.9 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H1A···Cl1 | 0.88 (4) | 2.15 (4) | 3.024 (3) | 177 (3) |
C2—H2···Cl1i | 0.98 (4) | 2.78 (4) | 3.745 (4) | 173 (2) |
C3—H3···Cl1ii | 0.98 (4) | 2.71 (4) | 3.445 (3) | 132 (3) |
C11—H11···N3Aiii | 0.90 (4) | 2.67 (4) | 3.390 (16) | 138 (3) |
C13A—H13A···O2Aiii | 0.96 | 2.34 | 3.21 (4) | 151 |
C13A—H13A···N3Aiii | 0.96 | 2.50 | 3.37 (4) | 150 |
Symmetry codes: (i) x, y+1, z; (ii) −x+3, −y+1, −z+1; (iii) −x+1/2, y+1/2, −z+3/2. |
Acknowledgements
JTM thanks Tulane University for support of the Tulane Crystallography Laboratory.
References
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