Crystal structure of 2-ethyl­quinazoline-4(3H)-thione

In the title compound, C₁₀H₁₀N₂S, all non-H atoms are almost coplanar [maximum deviation = 0.103 (1) Å]. In the crystal, N-H...S inter­actions form R₂²(8) rings linking pairs of mol­ecules related by inversion. The mol­ecular pairs are stacked along [100]. A herringbone arrangement of pairs in the [010] direction forms layers parallel to (010).

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.033
• wR factor = 0.087
• Data-to-parameter ratio = 18.8

checkCIF/PLATON results

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Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          2 Why ?

Alert level G
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............          1 Why ?
PLAT910_ALERT_3_G Missing # of FCF Reflections Below Th(Min) .....          2 Why ?
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600        327 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   1 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Structural commentary

The 2-ethyl-3H-quinazoline-4-thione molecule (Fig 1) is almost planer (apart from the ethyl hydrogens) with the ethyl group being twisted from the quinazoline-4-thione plane by 8.7 (2)°. N—H···S inter­actions form R₂²(8) rings to link pairs of molecules related by inversion. The pairs of molecules are stacked parallel to the a-axis (Fig 2). Adjacent pairs pack in a herring bone arrangement in the [010] direction to form layers parallel to the (010) plane. 2-(Substituted alkyl)-3H-quinazoline-4-thione derivatives can be obtained from double li­thia­tion of 2-alkyl-3H-quinazoline-4-thio­nes followed by reactions with electrophiles, including alkyl iodides, at low temperature in anhydrous THF (El-Hiti, 2004). Also, 3H-quinazoline-4-thio­nes are produced from the corresponding 3H-quinazoline-4-ones using phospho­rus penta­sulfide (Bogert et al., 1903; Ozturk et al., 2007; El-Hiti et al., 2011) or Lawesson's reagent (Segarra et al., 1998). 3H-Quinazoline-4-thio­nes have also been synthesized in one-step from reaction of 2-amino­benzo­nitriles and thio­amides in the presence of hydrogen bromide in various solvents on a steam bath for 1–4 h (Zoltewicz & Sharpless, 1976).

S2. Synthesis and crystallization

2-Ethyl-3H-quinazoline-4-thione was obtained in 92% yield from double li­thia­tion of 2-methyl-3H-quinazoline-4-thione with n-butyl­lithium at 78 ^οC in anhydrous THF under nitro­gen followed by reaction with iodo­methane (El-Hiti, 2004). Crystallization from methanol gave the title compound as yellow crystals. The NMR and low and high resolution mass spectra for the title compound were consistent with those reported (El-Hiti, 2004).

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were placed in calculated positions with C—H = 0.95 and 0.98Å and refined in riding mode, U_iso(H) = 1.5U_eq(C) for methyl H atoms and 1.2Ueq(C) for aromatic H atoms

Related literature

For the synthesis of quinazoline-4(3H)-thiones, see: Bogert et al. (1903); Zoltewicz & Sharpless (1976); Segarra et al. (1998); El-Hiti (2004); Ozturk et al. (2007); El-Hiti et al. (2011).

Computing details

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. A molecule of the title compound showing atom labels and 50% probability displacement ellipsoids for non-H atoms.
	Fig. 2. Crystal structure packing showing N—H···S contacts as dotted lines.

2-Ethylquinazoline-4(3H)-thione

Crystal data

C10H10N2S	Dx = 1.394 Mg m^−3
Mr = 190.26	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 3617 reflections
a = 5.8231 (3) Å	θ = 3.9–29.3°
b = 14.3214 (6) Å	µ = 0.31 mm^−1
c = 21.7365 (8) Å	T = 150 K
V = 1812.71 (14) Å^3	Plate, yellow
Z = 8	0.41 × 0.24 × 0.15 mm
F(000) = 800

Data collection

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer	2240 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	1973 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.020
ω scans	θmax = 29.8°, θmin = 3.0°
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2014)	h = −6→7
Tmin = 0.780, Tmax = 1.000	k = −19→14
7795 measured reflections	l = −23→29

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.033	H-atom parameters constrained
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.0416P)^2 + 0.7981P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2240 reflections	Δρmax = 0.30 e Å^−3
119 parameters	Δρmin = −0.25 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7433 (2)	0.57478 (9)	0.62537 (6)	0.0185 (3)
C2	0.6649 (2)	0.44643 (8)	0.55604 (5)	0.0178 (2)
C3	0.4705 (2)	0.42557 (8)	0.59550 (5)	0.0177 (3)
C4	0.4368 (2)	0.48131 (8)	0.64832 (5)	0.0183 (3)
C5	0.3171 (2)	0.35262 (9)	0.58239 (6)	0.0209 (3)
H5	0.3379	0.3158	0.5465	0.025*
C6	0.1366 (2)	0.33425 (9)	0.62146 (6)	0.0236 (3)
H6	0.0337	0.2845	0.6127	0.028*
C7	0.1046 (2)	0.38917 (9)	0.67440 (6)	0.0240 (3)
H7	−0.0197	0.3760	0.7013	0.029*
C8	0.2513 (2)	0.46175 (9)	0.68761 (6)	0.0218 (3)
H8	0.2272	0.4987	0.7233	0.026*
C9	0.8998 (2)	0.65696 (9)	0.63452 (6)	0.0227 (3)
H9A	0.8734	0.7023	0.6009	0.027*
H9B	1.0609	0.6354	0.6316	0.027*
C10	0.8668 (3)	0.70632 (9)	0.69567 (6)	0.0246 (3)
H10A	0.7058	0.7252	0.7000	0.037*
H10B	0.9652	0.7618	0.6972	0.037*
H10C	0.9080	0.6639	0.7293	0.037*
N1	0.78973 (18)	0.52156 (7)	0.57402 (5)	0.0188 (2)
H1	0.9086	0.5374	0.5513	0.023*
N2	0.57662 (19)	0.55697 (7)	0.66273 (5)	0.0199 (2)
S1	0.73978 (6)	0.38502 (2)	0.49367 (2)	0.02214 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0210 (6)	0.0177 (6)	0.0169 (6)	0.0022 (5)	−0.0006 (4)	−0.0010 (5)
C2	0.0203 (6)	0.0164 (5)	0.0166 (5)	0.0039 (5)	−0.0026 (5)	0.0008 (4)
C3	0.0194 (6)	0.0171 (6)	0.0167 (5)	0.0027 (5)	−0.0019 (5)	0.0020 (4)
C4	0.0197 (6)	0.0178 (6)	0.0172 (5)	0.0019 (5)	−0.0012 (4)	0.0010 (5)
C5	0.0237 (7)	0.0189 (6)	0.0202 (6)	0.0008 (5)	−0.0032 (5)	−0.0006 (5)
C6	0.0238 (7)	0.0212 (6)	0.0258 (6)	−0.0033 (5)	−0.0029 (5)	0.0012 (5)
C7	0.0213 (7)	0.0264 (7)	0.0244 (6)	−0.0013 (5)	0.0028 (5)	0.0038 (5)
C8	0.0242 (7)	0.0226 (6)	0.0186 (6)	0.0015 (5)	0.0016 (5)	0.0002 (5)
C9	0.0238 (7)	0.0208 (6)	0.0233 (6)	−0.0033 (5)	0.0041 (5)	−0.0040 (5)
C10	0.0292 (7)	0.0233 (6)	0.0214 (6)	−0.0047 (5)	0.0001 (5)	−0.0040 (5)
N1	0.0188 (5)	0.0194 (5)	0.0182 (5)	−0.0003 (4)	0.0030 (4)	−0.0024 (4)
N2	0.0220 (6)	0.0191 (5)	0.0187 (5)	−0.0006 (4)	0.0015 (4)	−0.0012 (4)
S1	0.0244 (2)	0.02191 (18)	0.02011 (17)	0.00029 (12)	0.00293 (12)	−0.00599 (12)

Geometric parameters (Å, º)

C1—N2	1.2908 (16)	C6—C7	1.4061 (19)
C1—N1	1.3784 (16)	C6—H6	0.9500
C1—C9	1.5017 (18)	C7—C8	1.3757 (19)
C2—N1	1.3560 (16)	C7—H7	0.9500
C2—C3	1.4514 (17)	C8—H8	0.9500
C2—S1	1.6737 (12)	C9—C10	1.5177 (17)
C3—C5	1.4038 (18)	C9—H9A	0.9900
C3—C4	1.4119 (16)	C9—H9B	0.9900
C4—N2	1.3910 (16)	C10—H10A	0.9800
C4—C8	1.4054 (18)	C10—H10B	0.9800
C5—C6	1.3766 (19)	C10—H10C	0.9800
C5—H5	0.9500	N1—H1	0.8800
N2—C1—N1	123.21 (12)	C6—C7—H7	119.6
N2—C1—C9	121.86 (11)	C7—C8—C4	120.08 (12)
N1—C1—C9	114.92 (11)	C7—C8—H8	120.0
N1—C2—C3	114.27 (11)	C4—C8—H8	120.0
N1—C2—S1	120.71 (10)	C1—C9—C10	113.84 (11)
C3—C2—S1	125.01 (10)	C1—C9—H9A	108.8
C5—C3—C4	119.83 (12)	C10—C9—H9A	108.8
C5—C3—C2	121.97 (11)	C1—C9—H9B	108.8
C4—C3—C2	118.19 (11)	C10—C9—H9B	108.8
N2—C4—C8	117.93 (11)	H9A—C9—H9B	107.7
N2—C4—C3	122.83 (11)	C9—C10—H10A	109.5
C8—C4—C3	119.22 (12)	C9—C10—H10B	109.5
C6—C5—C3	120.19 (12)	H10A—C10—H10B	109.5
C6—C5—H5	119.9	C9—C10—H10C	109.5
C3—C5—H5	119.9	H10A—C10—H10C	109.5
C5—C6—C7	119.94 (12)	H10B—C10—H10C	109.5
C5—C6—H6	120.0	C2—N1—C1	124.53 (11)
C7—C6—H6	120.0	C2—N1—H1	117.7
C8—C7—C6	120.73 (13)	C1—N1—H1	117.7
C8—C7—H7	119.6	C1—N2—C4	116.89 (11)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···S1^i	0.88	2.53	3.3854 (11)	166

Symmetry code: (i) −x+2, −y+1, −z+1.