1,6,6-Trimethyl-1H-chromeno[6,7-d]thia­zol-2(6H)-one

Abstract

The title compound, C₁₃H₁₃NO₂S, was prepared by a thermocyclization reaction from 3-methyl-6-(2-methyl­but-3-yn-2-yl­oxy)benzo[d]thia­zol-2(3H)-one. In the crystal structure, the methyl­thia­zole unit is planar, while the pyran ring assumes a screw-boat conformation. Intra­molecular C—H⋯O hydrogen bonding helps to stabilize the molecular structure.

Related literature

For general background, see: Gunatilaka et al. (1994 ▶); Ucar et al. (1998 ▶). For details of the synthesis, see: Delhomel et al. (2001 ▶).

Experimental

Crystal data

• C₁₃H₁₃NO₂S

• M _r = 247.30

• Triclinic,

• a = 7.376 (2) Å

• b = 8.395 (2) Å

• c = 10.536 (2) Å

• α = 106.13 (2)°

• β = 98.16 (2)°

• γ = 94.08 (2)°

• V = 616.2 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 0.25 mm⁻¹

• T = 298 (2) K

• 0.20 × 0.20 × 0.20 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: none

• 2765 measured reflections

• 2207 independent reflections

• 1387 reflections with I > 2σ(I)

• R _int = 0.023

• 3 standard reflections frequency: 60 min intensity decay: 0.5%

Refinement

• R[F ² > 2σ(F ²)] = 0.076

• wR(F ²) = 0.216

• S = 1.05

• 2207 reflections

• 157 parameters

• H-atom parameters constrained

• Δρ_max = 0.91 e Å⁻³

• Δρ_min = −0.68 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1984 ▶); cell refinement: CAD-4 Software; data reduction: CAD-4 Software; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

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
C7—H7⋯O1i	0.93	2.56	3.331 (5)	140

Symmetry code: (i) .

supplementary crystallographic information

Comment

2,2-Dimethyl-2H-benzopyran fused thiazolone is a novel potential bioactive core (Gunatilaka et al. 1994; Ucar et al. 1998). As part of our research program on new antitumor and antiviral agents based on bioisosterism, we synthesized the title compound and report here its crystal structure (Fig. 1).

The compound is a three rings-fused heterocycle compound. The methyl thiazole moiety shows a planar structure. The pyran ring assumes a screw-boat conformation. The C6–C7 bond distance of 1.312 (5) Å indicates a typical C═C double bond. Intramolecular C—H···O hydrogen bonding helps to stabilize the crystal structure (Table 1 and Fig. 2).

Experimental

The title compound was synthesized by the thermo-cyclization reaction of 3-methyl-6-(2-methylbut-3-yn-2-yloxy)benzo[d]thiazol-2(3H)-one. A mixture of 6-hydroxy-3-methyl-2(3H)-benzothiazolone (508 mg, 2.6 mmol) (Delhomel et al. 2001), 3-methyl-3-chloro-but-1-yne (320 mg, 3.12 mmol) and K₂CO₃ (1.43 g, 10.4 mmol) was stirred in acetone (30 ml) for 5 h under reflux condition, then filtered and removed the solvent. To the residue was added N,N-diethylaniline (5 ml) and further refluxed for 2 h. The resulting solution was poured to ice water (100 ml) and extracted with acetyl acetate, and the organic layer was dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was isolated by chromatography on silica gel column with petroleum ether/EtOAc (18/1) as eluent to afford the pure compound. The solid was collected and recrystallized from acetyl acetate to give colorless crystals which were available for the single-crystal X-ray diffraction analysis. Yield: 33.5%.

Refinement

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 Å for aromatic H atoms and 0.96 Å for methyl H atoms, and refined in riding mode with U_iso(H) =1.2U_eq(C) for aromatic H atoms and U_iso(H) = 1.5U_eq(C) for methyl H atoms.

Figures

Fig. 1.

The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms.

Fig. 2.

The packing of (I), viewed down the c axis, showing one demensional supra-molecular chain connected by C—H···Oi hydrogen bonding [symmetry code: (i) = x, y + 1, z + 1). H atoms not involved in hydrogen bonding have been omitted.

Crystal data

C13H13NO2S	Z = 2
Mr = 247.30	F000 = 260
Triclinic, P1	Dx = 1.333 Mg m−3
Hall symbol: -P 1	Melting point = 376–378 K
a = 7.376 (2) Å	Mo Kα radiation λ = 0.71073 Å
b = 8.395 (2) Å	Cell parameters from 25 reflections
c = 10.536 (2) Å	θ = 10.2–13.7º
α = 106.13 (2)º	µ = 0.25 mm−1
β = 98.16 (2)º	T = 298 (2) K
γ = 94.08 (2)º	Parallelepiped, colourless
V = 616.2 (3) Å3	0.20 × 0.20 × 0.20 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	Rint = 0.023
Radiation source: fine-focus sealed tube	θmax = 25.2º
Monochromator: graphite	θmin = 2.0º
T = 298(2) K	h = −1→8
ω/2θ scans	k = −10→10
Absorption correction: none	l = −12→12
2765 measured reflections	3 standard reflections
2207 independent reflections	every 60 min
1387 reflections with I > 2σ(I)	intensity decay: 0.5%

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.076	H-atom parameters constrained
wR(F2) = 0.216	w = 1/[σ2(Fo2) + (0.1546P)2] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
2207 reflections	Δρmax = 0.91 e Å−3
157 parameters	Δρmin = −0.68 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Special details

Experimental. 1H NMR (CDCl3, 400 MHz): δ 6.87 (s, 1H, 9-H); 6.64 (s, 1H, 4-H); 6.35 (1H, d, J = 9.78 Hz, 8-H); 5.68 (d, 1H, J = 9.78 Hz, 7-H); 3.40 (s, 3H, 1-CH3); 1.43 (s, 6H, 6-CH3). MS: m/z (%) 247 (M+, 22.17).

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.

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 > σ(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.

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

	x	y	z	Uiso*/Ueq
S1	0.72819 (14)	0.52182 (13)	−0.25523 (9)	0.0529 (4)
N1	0.7791 (4)	0.3420 (4)	−0.0937 (3)	0.0438 (7)
O1	0.8000 (4)	0.2061 (4)	−0.3119 (3)	0.0670 (9)
O2	0.6410 (4)	0.9748 (3)	0.1700 (2)	0.0456 (7)
C1	0.7748 (5)	0.3288 (5)	−0.2252 (4)	0.0510 (10)
C2	0.8103 (5)	0.2021 (5)	−0.0421 (4)	0.0572 (11)
H2A	0.8403	0.1115	−0.1114	0.086*
H2B	0.7008	0.1671	−0.0128	0.086*
H2C	0.9105	0.2348	0.0321	0.086*
C3	0.7480 (4)	0.4981 (4)	−0.0139 (3)	0.0383 (8)
C4	0.7478 (4)	0.5454 (4)	0.1217 (4)	0.0410 (8)
H4	0.7695	0.4696	0.1703	0.049*
C5	0.7150 (4)	0.7070 (4)	0.1869 (3)	0.0384 (8)
C6	0.7087 (5)	0.7649 (5)	0.3289 (4)	0.0471 (9)
H6	0.7087	0.6891	0.3786	0.056*
C7	0.7028 (5)	0.9237 (5)	0.3877 (4)	0.0509 (10)
H7	0.6938	0.9579	0.4782	0.061*
C8	0.7103 (5)	1.0517 (4)	0.3131 (3)	0.0454 (9)
C9	0.9067 (6)	1.1285 (5)	0.3310 (4)	0.0629 (12)
H9A	0.9809	1.0437	0.2938	0.094*
H9B	0.9534	1.1774	0.4248	0.094*
H9C	0.9108	1.2132	0.2860	0.094*
C10	0.5804 (6)	1.1829 (6)	0.3549 (4)	0.0661 (13)
H10A	0.5912	1.2639	0.3068	0.099*
H10B	0.6126	1.2374	0.4494	0.099*
H10C	0.4558	1.1301	0.3349	0.099*
C11	0.6830 (4)	0.8184 (4)	0.1118 (3)	0.0376 (8)
C12	0.6816 (5)	0.7719 (4)	−0.0248 (3)	0.0403 (8)
H12	0.6586	0.8470	−0.0739	0.048*
C13	0.7152 (5)	0.6107 (4)	−0.0871 (3)	0.0407 (8)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
S1	0.0508 (6)	0.0578 (7)	0.0427 (6)	0.0037 (4)	0.0053 (4)	0.0046 (4)
N1	0.0257 (14)	0.0416 (17)	0.0569 (18)	0.0002 (12)	0.0024 (12)	0.0056 (14)
O1	0.0605 (19)	0.0622 (19)	0.0608 (18)	0.0140 (15)	0.0033 (14)	−0.0090 (15)
O2	0.0475 (15)	0.0445 (14)	0.0390 (13)	0.0094 (11)	−0.0031 (10)	0.0073 (11)
C1	0.0264 (18)	0.058 (2)	0.052 (2)	−0.0016 (16)	−0.0012 (15)	−0.0037 (18)
C2	0.032 (2)	0.050 (2)	0.082 (3)	0.0036 (17)	0.0020 (19)	0.012 (2)
C3	0.0212 (15)	0.0409 (19)	0.0482 (19)	−0.0024 (13)	0.0028 (13)	0.0083 (16)
C4	0.0258 (17)	0.046 (2)	0.050 (2)	−0.0022 (14)	−0.0010 (14)	0.0166 (17)
C5	0.0239 (16)	0.048 (2)	0.0385 (18)	−0.0033 (14)	−0.0017 (13)	0.0108 (15)
C6	0.042 (2)	0.054 (2)	0.045 (2)	0.0060 (16)	0.0023 (16)	0.0151 (17)
C7	0.047 (2)	0.065 (3)	0.0359 (18)	0.0069 (18)	−0.0001 (16)	0.0098 (18)
C8	0.041 (2)	0.049 (2)	0.0383 (19)	0.0072 (16)	−0.0015 (15)	0.0032 (16)
C9	0.046 (2)	0.066 (3)	0.067 (3)	−0.006 (2)	−0.005 (2)	0.013 (2)
C10	0.068 (3)	0.072 (3)	0.049 (2)	0.029 (2)	0.000 (2)	0.003 (2)
C11	0.0227 (16)	0.0403 (19)	0.0435 (18)	−0.0010 (13)	−0.0011 (13)	0.0065 (15)
C12	0.0338 (18)	0.044 (2)	0.0393 (18)	−0.0031 (14)	−0.0026 (14)	0.0121 (15)
C13	0.0298 (17)	0.044 (2)	0.0401 (18)	−0.0064 (14)	−0.0014 (13)	0.0060 (15)

Geometric parameters (Å, °)

S1—C13	1.740 (4)	C5—C6	1.447 (5)
S1—C1	1.783 (4)	C6—C7	1.312 (5)
N1—C1	1.354 (5)	C6—H6	0.9300
N1—C3	1.401 (4)	C7—C8	1.500 (5)
N1—C2	1.444 (5)	C7—H7	0.9300
O1—C1	1.218 (4)	C8—C9	1.507 (5)
O2—C11	1.364 (4)	C8—C10	1.525 (5)
O2—C8	1.464 (4)	C9—H9A	0.9599
C2—H2A	0.9599	C9—H9B	0.9599
C2—H2B	0.9599	C9—H9C	0.9599
C2—H2C	0.9599	C10—H10A	0.9599
C3—C4	1.373 (5)	C10—H10B	0.9599
C3—C13	1.389 (5)	C10—H10C	0.9599
C4—C5	1.395 (5)	C11—C12	1.381 (5)
C4—H4	0.9300	C12—C13	1.388 (5)
C5—C11	1.395 (5)	C12—H12	0.9300
C13—S1—C1	91.10 (17)	C8—C7—H7	119.1
C1—N1—C3	115.4 (3)	O2—C8—C7	110.5 (3)
C1—N1—C2	121.4 (3)	O2—C8—C9	109.2 (3)
C3—N1—C2	123.2 (3)	C7—C8—C9	109.5 (3)
C11—O2—C8	118.1 (3)	O2—C8—C10	103.6 (3)
O1—C1—N1	126.6 (4)	C7—C8—C10	111.9 (3)
O1—C1—S1	123.7 (3)	C9—C8—C10	112.1 (3)
N1—C1—S1	109.8 (3)	C8—C9—H9A	109.5
N1—C2—H2A	109.5	C8—C9—H9B	109.5
N1—C2—H2B	109.5	H9A—C9—H9B	109.5
H2A—C2—H2B	109.5	C8—C9—H9C	109.5
N1—C2—H2C	109.5	H9A—C9—H9C	109.5
H2A—C2—H2C	109.5	H9B—C9—H9C	109.5
H2B—C2—H2C	109.5	C8—C10—H10A	109.5
C4—C3—C13	120.2 (3)	C8—C10—H10B	109.5
C4—C3—N1	127.2 (3)	H10A—C10—H10B	109.5
C13—C3—N1	112.6 (3)	C8—C10—H10C	109.5
C3—C4—C5	120.2 (3)	H10A—C10—H10C	109.5
C3—C4—H4	119.9	H10B—C10—H10C	109.5
C5—C4—H4	119.9	O2—C11—C12	117.5 (3)
C11—C5—C4	118.8 (3)	O2—C11—C5	120.8 (3)
C11—C5—C6	117.9 (3)	C12—C11—C5	121.6 (3)
C4—C5—C6	123.4 (3)	C11—C12—C13	118.4 (3)
C7—C6—C5	120.3 (4)	C11—C12—H12	120.8
C7—C6—H6	119.8	C13—C12—H12	120.8
C5—C6—H6	119.8	C12—C13—C3	120.8 (3)
C6—C7—C8	121.8 (3)	C12—C13—S1	128.0 (3)
C6—C7—H7	119.1	C3—C13—S1	111.2 (3)
C3—N1—C1—O1	179.1 (3)	C6—C7—C8—O2	25.8 (5)
C2—N1—C1—O1	−2.0 (5)	C6—C7—C8—C9	−94.5 (4)
C3—N1—C1—S1	−0.2 (3)	C6—C7—C8—C10	140.6 (4)
C2—N1—C1—S1	178.6 (2)	C8—O2—C11—C12	−155.9 (3)
C13—S1—C1—O1	−179.8 (3)	C8—O2—C11—C5	27.9 (4)
C13—S1—C1—N1	−0.4 (2)	C4—C5—C11—O2	176.6 (3)
C1—N1—C3—C4	−178.9 (3)	C6—C5—C11—O2	−2.2 (5)
C2—N1—C3—C4	2.2 (5)	C4—C5—C11—C12	0.5 (5)
C1—N1—C3—C13	1.0 (4)	C6—C5—C11—C12	−178.2 (3)
C2—N1—C3—C13	−177.9 (3)	O2—C11—C12—C13	−176.9 (3)
C13—C3—C4—C5	−0.2 (5)	C5—C11—C12—C13	−0.8 (5)
N1—C3—C4—C5	179.7 (3)	C11—C12—C13—C3	0.5 (5)
C3—C4—C5—C11	−0.1 (5)	C11—C12—C13—S1	−177.9 (3)
C3—C4—C5—C6	178.6 (3)	C4—C3—C13—C12	0.0 (5)
C11—C5—C6—C7	−10.8 (5)	N1—C3—C13—C12	−180.0 (3)
C4—C5—C6—C7	170.5 (3)	C4—C3—C13—S1	178.7 (2)
C5—C6—C7—C8	−2.6 (5)	N1—C3—C13—S1	−1.3 (3)
C11—O2—C8—C7	−37.9 (4)	C1—S1—C13—C12	179.5 (3)
C11—O2—C8—C9	82.5 (4)	C1—S1—C13—C3	1.0 (2)
C11—O2—C8—C10	−157.9 (3)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···O1i	0.93	2.56	3.331 (5)	140

Symmetry codes: (i) x, y+1, z+1.