Crystal structure of 3-amino-2-ethyl­quinazolin-4(3H)-one

Gamal A El-Hiti; Keith Smith; Amany S Hegazy; Mohammed Baashen; Benson M Kariuki

doi:10.1107/S2056989015014450

. 2015 Aug 6;71(Pt 9):o650–o651. doi: 10.1107/S2056989015014450

Crystal structure of 3-amino-2-ethylquinazolin-4(3H)-one

Gamal A El-Hiti ^a,^*, Keith Smith ^b, Amany S Hegazy ^b, Mohammed Baashen ^c, Benson M Kariuki ^b,^‡

PMCID: PMC4555403 PMID: 26396885

Abstract

The molecule of the title compound, C₁₀H₁₁N₃O, is planar, including the ethyl group, as indicated by the N—C—C—C torsion angle of 1.5 (2)°. In the crystal, inversion-related molecules are stacked along the a axis. Molecules are oriented head-to-tail and display π–π interactions with a centroid-to-centroid distance of 3.6664 (8) Å. N—H⋯O hydrogen bonds between molecules generate a ‘step’ structure through formation of an R ₂ ²(10) ring.

Keywords: crystal structure, 3-amino-2-ethylquinazolin-4(3H)-one, π–π interactions

Related literature

For related compounds, see: Ma et al. (2013 ▸); Adib et al. (2012 ▸); Xu et al. (2012 ▸); Sasmal et al. (2012 ▸); Kumar et al. (2011 ▸); Rohini et al. (2010 ▸); Davies et al. (2010 ▸). For quinazolin-4(3H)-one ring-system modification through lithiation, see: Smith et al. (2004 ▸, 1996 ▸, 1995 ▸). For the crystal structures of related compounds, see: El-Hiti et al. (2014 ▸); Yang et al. (2009 ▸); Coogan et al. (1999 ▸). graphic file with name e-71-0o650-scheme1.jpg

Experimental

Crystal data

C₁₀H₁₁N₃O
M _r = 189.22
Triclinic,
a = 7.0230 (5) Å
b = 7.6198 (7) Å
c = 9.7868 (6) Å
α = 69.709 (7)°
β = 89.242 (5)°
γ = 75.191 (7)°
V = 473.27 (7) Å³
Z = 2
Cu Kα radiation
μ = 0.73 mm⁻¹
T = 293 K
0.38 × 0.20 × 0.08 mm

Data collection

Agilent SuperNova Dual Source diffractometer with an Atlas detector
Absorption correction: Gaussian (CrysAlis PRO; Agilent, 2014 ▸) T _min = 0.741, T _max = 0.924
3303 measured reflections
1858 independent reflections
1657 reflections with I > 2σ(I)
R _int = 0.015
Standard reflections: 0

Refinement

R[F ² > 2σ(F ²)] = 0.061
wR(F ²) = 0.196
S = 1.07
1858 reflections
136 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2014 ▸); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: WinGX (Farrugia, 2012 ▸) and CHEMDRAW Ultra (Cambridge Soft, 2001 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S2056989015014450/hg5454sup1.cif

e-71-0o650-sup1.cif^{(126.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015014450/hg5454Isup2.hkl

e-71-0o650-Isup2.hkl^{(102.3KB, hkl)}

Click here for additional data file.^{(3.9KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015014450/hg5454Isup3.cml

Click here for additional data file.^{(1.2MB, tif)}

10 11 3 . DOI: 10.1107/S2056989015014450/hg5454fig1.tif

The asymmetric unit of C₁₀H₁₁N₃O, with atom labels and 50% probability displacement ellipsoids for non-hydrogen atoms.

Click here for additional data file.^{(1.5MB, tif)}

. DOI: 10.1107/S2056989015014450/hg5454fig2.tif

Crystal packing with hydrogen-bonding contacts shown as dotted lines.

CCDC reference: 1416070

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N3H3AO1ⁱ	0.91(2)	2.12(2)	2.974(2)	157.1(19)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors extend their appreciation to the British Council, Riyadh, Saudi Arabia, for funding this research and to Cardiff University for continued support.

supplementary crystallographic information

S1. Introduction

Quinazolines have various interesting biological applications (Sasmal et al., 2012; Rohini et al., 2010). Quinazolin-4(3H)-ones synthesis involves use of various synthetic procedures. The most common starting materials are 2-aminobenzonitrile (Ma et al., 2013), 2-bromobenzamides (Xu et al., 2012), isatoic anhydride (Adib et al., 2012), anthranilic acid (Kumar et al., 2011), methyl 2-aminobenzoate (Davies et al., 2010). Lithiation of 2-n-alkyl- and 2-unsubstituted 3-acylaminoquinazolin-4(3H)-ones with a lithium reagent in tetrahydrofuran at a low temperature followed by reactions of various electrophiles with the lithium reagents produced in-situ gave the corresponding 2-substituted derivatives in good to excellent yields (Smith et al., 2004, 1996, 1995). For the X-ray structures for related compounds, see: El-Hiti et al. (2014); Yang et al. (2009); Coogan et al. (1999).

S2. Experimental

S2.1. Synthesis and crystallization

A mixture of methyl 2-aminobenzoate and propionic anhydride (1.4 mole equivalents) was heated for 30 minutes at 105 °C. The mixture was cooled to 75 °C and diluted with ethanol (50 mL). Hydrazine monohydrate (10 mole equivalents) was added in a dropwise manner over 10 minutes and the mixture was refluxed for 1 h. The mixture was cooled to room temperature and the solvent was removed under reduced pressure. The residue obtained was purified by column chromatography (silica gel hexane/diethyl ether in 4:1 by volume) to give 3-amino-2-ethylquinazolin-4(3H)-one in 82% yield (Davies et al., 2010). Crystallization from a mixture of ethyl acetate and diethyl ether (1:2 by volume) gave colourless crystals of the title compound. The spectroscopic data for the title compound were identical with those reported (Davies et al., 2010).

S2.2. Refinement

H atoms were positioned geometrically and refined using a riding model with U_iso(H) constrained to be 1.2 times U_eq for the atom it is bonded to except for methyl groups where it was 1.5 times with free rotation about the C—C bond. The amide hydrogen atoms were located in the difference Fourier map and refined freely.

S3. Results and discussion

The asymmetric unit comprises a molecule of C₁₀H₁₁N₃O (Fig. 1). The molecule is planar, including the ethyl group as indicated by the N2—C1—C9—C10 torsion angle of 1.5 (2)°. Inversion related molecules are stacked along the a axis (Fig. 2). Molecules (x,y,z) and (1-x, -y,1-z) are oriented head-to-tail and display π - π interaction with a centroid to centroid distance of 3.66 (2)Å. N—H···O hydrogen bonds between molecules (x,y,z) and (-x,-y+1, -z+1) generate a 'step' structure through formation of a R₂²(10) ring.