Ethyl 2-amino-4-phenyl-4H-1-benzo­thieno[3,2-b]pyran-3-carboxyl­ate

Boughaleb, A.; Zouihri, H.; Gmouh, S.; Kerbal, A.; El yazidi, M.

doi:10.1107/S1600536811027152

organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page o2106

doi:10.1107/S1600536811027152

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Ethyl 2-amino-4-phenyl-4H-1-benzothieno[3,2-b]pyran-3-carboxylate

Adil Boughaleb,^a Hafid Zouihri,^b Said Gmouh,^c Abdelali Kerbal ^a and Mohamed El yazidi ^a ^*

^aDépartement de Chimie, Faculté des Sciences, Dhar Mehraz, BP 1796 Atlas, 30000 Fés, Morocco, ^bLaboratoire de Diffraction des Rayons X, Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco, and ^cCentre National pour la Recherche Scientifique et Technique, Rabat, Morocco
^*Correspondence e-mail: elyazidimohamed@hotmail.com

(Received 14 June 2011; accepted 6 July 2011; online 23 July 2011)

The title heterocyclic compound, C₂₀H₁₇NO₃S, was synthesized by condensation of ethyl cyanoacetate with (Z)-2-benzylidenebenzo[b]thiophen-3(2H)-one in the presence of a basic catalyst in ethanol. The phenyl and ester groups make dihedral angles of 77.67 (6) and 8.52 (6)°, respectively, with the benzothienopyran ring system [maximum r.m.s. deviation = 0.1177 (13) Å]. In the crystal, centrosymmetric dimers are formed through pairs of N—H⋯O hydrogen bonds between the amine and ester groups. Intermolecular C—H⋯N hydrogen bonds and C—H⋯π interactions involving the thiophene ring are also observed.

Related literature

For general background to Michael addition reactions, see: Perlmutter (1992 ); Czarnocki et al. (2005 ); Rossiter & Swingle (1992 ).

Experimental

Crystal data

C₂₀H₁₇NO₃S
M_r = 351.41
Monoclinic, P 2₁ /n
a = 8.6612 (3) Å
b = 5.9156 (2) Å
c = 32.3008 (10) Å
β = 94.962 (2)°
V = 1648.77 (9) Å³
Z = 4
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 296 K
0.25 × 0.14 × 0.12 mm

Data collection

Bruker APEXII CCD detector diffractometer
21683 measured reflections
3608 independent reflections
3189 reflections with I > 2σ(I)
R_int = 0.031

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.086
S = 1.04
3608 reflections
233 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the thiophene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O2ⁱ	0.838 (19)	2.285 (19)	2.9143 (16)	132.1 (15)
C10—H10⋯N1ⁱⁱ	0.98	2.57	3.5189 (17)	164
C15—H15⋯Cg1ⁱⁱⁱ	0.93	2.95	3.7493 (15)	145
Symmetry codes: (i) -x, -y+1, -z; (ii) x, y+1, z; (iii) x+1, y, z.

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811027152/bh2365sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811027152/bh2365Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811027152/bh2365Isup3.cml

checkCIF report

Comment top

The Michael addition of carbanions to the C═C double bond of α,β-unsaturated ketones, nitriles, amides and esters is a method of choice for the formation of C—C bonds (Czarnocki et al., 2005; Rossiter & Swingle, 1992; Perlmutter, 1992).

In this work we have studied the behavior of ethylcyanoacetate with respect to (Z)-2-benzylidenebenzo[b]thiophen-3(2H)-one and derivatives in ethanol, with the presence of piperidine as catalyst. We have shown that cyclocondensation starts with a Michael 1,4-addition, followed by intramolecular cyclization via nucleophilic addition of the hydroxyl group to the cyano group and not onto the carboxylate, to give the tricyclic heterocycle ethyl 2-amino-4-phenyl-4H-[1] benzothieno[3,2-b]pyran-3-carboxylate. The structural study by X-ray diffraction is in perfect agreement with the results of spectroscopic analysis: IR, ¹H- and ¹³C-NMR.

In the title compound, C₂₀H₁₇NO₃S (Fig. 1), the phenyl and ester groups make dihedral angles of 77.67 (6)° and 8.52 (6)°, respectively, with the benzothienopyran ring system. In the crystal, two molecules are linked about a center of inversion by pairs of N—H···O hydrogen bonds, generating a dimer (Fig. 2). Intermolecular C—H···N hydrogen bonds and C—H···π interactions (between C15—H15 bond of the phenyl group and the centroid of the thiophene ring with symmetry code: x+1, y, z) are also observed (Table 1).

Related literature top

For general background to Michael addition reactions, see: Perlmutter (1992); Czarnocki et al. (2005); Rossiter & Swingle (1992).

Experimental top

In a 100 ml flask equipped with a condenser, was dissolved 4 mmol of (Z)-2-benzylidenebenzo[b]thiophen-3(2H)-one and 5 mmol of ethyl cyanoacetate in 30 ml of ethanol. Then, 1ml of piperidine was added, and the reaction mixture was refluxed for 6 h. Thin layer hromatography revealed the formation of a single product. The organic phase was evaporated under reduced pressure. The resulting residue was recrystallized from ethanol.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. Molecular view of the title compound showing displacement ellipsoids at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.
	Fig. 2. Partial view of the crystal packing, showing the N—H···O bonded dimers (symmetry code: -x, -y+1, -z). H atoms not involved in hydrogen bonds have been omitted for clarity.

Ethyl 2-amino-4-phenyl-4H-1-benzothieno[3,2-b]pyran-3-carboxylate top

Crystal data top

C₂₀H₁₇NO₃S	F(000) = 736
M_r = 351.41	D_x = 1.416 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 232 reflections
a = 8.6612 (3) Å	θ = 2.6–25.3°
b = 5.9156 (2) Å	µ = 0.22 mm⁻¹
c = 32.3008 (10) Å	T = 296 K
β = 94.962 (2)°	Prism, colourless
V = 1648.77 (9) Å³	0.25 × 0.14 × 0.12 mm
Z = 4

Data collection top

Bruker APEXII CCD detector diffractometer	3189 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.031
Graphite monochromator	θ_max = 27.0°, θ_min = 2.4°
ω and ϕ scans	h = −11→11
21683 measured reflections	k = −7→7
3608 independent reflections	l = −41→37

Refinement top

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.086	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0386P)² + 0.7884P] where P = (F_o² + 2F_c²)/3
3608 reflections	(Δ/σ)_max = 0.001
233 parameters	Δρ_max = 0.30 e Å⁻³
2 restraints	Δρ_min = −0.22 e Å⁻³
0 constraints

Crystal data top

C₂₀H₁₇NO₃S	V = 1648.77 (9) Å³
M_r = 351.41	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.6612 (3) Å	µ = 0.22 mm⁻¹
b = 5.9156 (2) Å	T = 296 K
c = 32.3008 (10) Å	0.25 × 0.14 × 0.12 mm
β = 94.962 (2)°

Data collection top

Bruker APEXII CCD detector diffractometer	3189 reflections with I > 2σ(I)
21683 measured reflections	R_int = 0.031
3608 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	2 restraints
wR(F²) = 0.086	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.30 e Å⁻³
3608 reflections	Δρ_min = −0.22 e Å⁻³
233 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	0.18188 (4)	1.17172 (6)	0.191397 (10)	0.02581 (10)
O3	0.03012 (11)	0.62652 (16)	0.13342 (3)	0.0244 (2)
C9	0.15146 (15)	0.8299 (2)	0.08005 (4)	0.0209 (3)
C7	0.07313 (15)	0.8007 (2)	0.16060 (4)	0.0209 (3)
C12	0.39539 (14)	1.0315 (2)	0.11368 (4)	0.0191 (3)
C10	0.21849 (14)	1.0162 (2)	0.10886 (4)	0.0193 (3)
H10	0.1785	1.1610	0.0978	0.023*
C11	0.15652 (15)	0.9814 (2)	0.15042 (4)	0.0206 (3)
C6	0.02270 (15)	0.8029 (2)	0.20170 (4)	0.0219 (3)
C18	0.16810 (15)	0.8490 (2)	0.03571 (4)	0.0233 (3)
C8	0.06481 (15)	0.6545 (2)	0.09321 (4)	0.0212 (3)
C1	0.07339 (15)	1.0023 (2)	0.22215 (4)	0.0233 (3)
C2	0.03563 (16)	1.0502 (3)	0.26251 (4)	0.0280 (3)
H2	0.0692	1.1827	0.2759	0.034*
C5	−0.06701 (16)	0.6470 (3)	0.22184 (4)	0.0263 (3)
H5	−0.1011	0.5140	0.2087	0.032*
C4	−0.10381 (16)	0.6953 (3)	0.26180 (4)	0.0300 (3)
H4	−0.1633	0.5936	0.2756	0.036*
C13	0.48520 (16)	0.8567 (2)	0.13167 (4)	0.0246 (3)
H13	0.4379	0.7236	0.1392	0.030*
C17	0.46835 (16)	1.2279 (2)	0.10227 (4)	0.0240 (3)
H17	0.4097	1.3453	0.0899	0.029*
C19	0.26683 (17)	1.0704 (3)	−0.01709 (4)	0.0287 (3)
H19A	0.1676	1.0940	−0.0328	0.034*
H19B	0.3159	0.9389	−0.0282	0.034*
C3	−0.05272 (17)	0.8949 (3)	0.28169 (4)	0.0303 (3)
H3	−0.0790	0.9234	0.3085	0.036*
C16	0.62864 (17)	1.2511 (3)	0.10919 (5)	0.0294 (3)
H16	0.6764	1.3835	0.1015	0.035*
C14	0.64516 (16)	0.8792 (3)	0.13841 (4)	0.0292 (3)
H14	0.7043	0.7608	0.1503	0.035*
C15	0.71678 (16)	1.0774 (3)	0.12754 (4)	0.0305 (3)
H15	0.8236	1.0935	0.1326	0.037*
C20	0.36800 (19)	1.2749 (3)	−0.01999 (5)	0.0361 (4)
H20A	0.3148	1.4059	−0.0110	0.054*
H20B	0.3914	1.2954	−0.0483	0.054*
H20C	0.4625	1.2542	−0.0026	0.054*
O1	0.24544 (11)	1.03714 (17)	0.02657 (3)	0.0257 (2)
O2	0.11868 (12)	0.71560 (19)	0.00872 (3)	0.0319 (2)
N1	0.00146 (15)	0.4847 (2)	0.06999 (4)	0.0279 (3)
H1A	−0.062 (2)	0.392 (3)	0.0809 (5)	0.034*
H1B	0.009 (2)	0.484 (3)	0.0443 (6)	0.034*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.02830 (19)	0.02802 (19)	0.02170 (17)	−0.00438 (14)	0.00562 (13)	−0.00647 (14)
O3	0.0311 (5)	0.0234 (5)	0.0187 (5)	−0.0041 (4)	0.0023 (4)	−0.0009 (4)
C9	0.0206 (6)	0.0245 (7)	0.0173 (6)	0.0016 (5)	−0.0005 (5)	−0.0016 (5)
C7	0.0192 (6)	0.0240 (7)	0.0191 (6)	0.0016 (5)	−0.0001 (5)	−0.0022 (5)
C12	0.0204 (6)	0.0240 (6)	0.0130 (5)	0.0008 (5)	0.0021 (5)	−0.0034 (5)
C10	0.0193 (6)	0.0209 (6)	0.0176 (6)	0.0024 (5)	0.0005 (5)	−0.0004 (5)
C11	0.0187 (6)	0.0243 (7)	0.0187 (6)	0.0019 (5)	0.0009 (5)	−0.0026 (5)
C6	0.0179 (6)	0.0284 (7)	0.0194 (6)	0.0054 (5)	0.0003 (5)	0.0005 (5)
C18	0.0218 (6)	0.0272 (7)	0.0206 (6)	0.0023 (5)	0.0000 (5)	−0.0018 (5)
C8	0.0211 (6)	0.0233 (7)	0.0185 (6)	0.0040 (5)	−0.0016 (5)	−0.0009 (5)
C1	0.0192 (6)	0.0297 (7)	0.0210 (6)	0.0042 (5)	0.0015 (5)	0.0004 (6)
C2	0.0274 (7)	0.0355 (8)	0.0209 (6)	0.0068 (6)	0.0016 (5)	−0.0035 (6)
C5	0.0233 (7)	0.0315 (7)	0.0241 (7)	0.0005 (6)	0.0011 (5)	0.0038 (6)
C4	0.0240 (7)	0.0422 (9)	0.0243 (7)	0.0034 (6)	0.0043 (5)	0.0094 (6)
C13	0.0254 (7)	0.0256 (7)	0.0227 (6)	0.0008 (5)	0.0007 (5)	0.0017 (6)
C17	0.0252 (7)	0.0249 (7)	0.0222 (6)	0.0017 (5)	0.0034 (5)	0.0021 (6)
C19	0.0335 (8)	0.0369 (8)	0.0161 (6)	0.0048 (6)	0.0034 (5)	0.0020 (6)
C3	0.0263 (7)	0.0460 (9)	0.0191 (6)	0.0104 (6)	0.0047 (5)	0.0023 (6)
C16	0.0266 (7)	0.0333 (8)	0.0292 (7)	−0.0055 (6)	0.0073 (6)	0.0016 (6)
C14	0.0246 (7)	0.0341 (8)	0.0282 (7)	0.0072 (6)	−0.0015 (6)	0.0021 (6)
C15	0.0192 (7)	0.0442 (9)	0.0283 (7)	−0.0003 (6)	0.0026 (5)	−0.0021 (7)
C20	0.0381 (9)	0.0423 (9)	0.0289 (8)	0.0019 (7)	0.0082 (6)	0.0084 (7)
O1	0.0322 (5)	0.0294 (5)	0.0157 (4)	−0.0024 (4)	0.0027 (4)	0.0003 (4)
O2	0.0390 (6)	0.0359 (6)	0.0206 (5)	−0.0061 (5)	0.0010 (4)	−0.0076 (4)
N1	0.0353 (7)	0.0262 (6)	0.0219 (6)	−0.0057 (5)	0.0001 (5)	−0.0029 (5)

Geometric parameters (Å, º) top

S1—C11	1.7371 (13)	C5—H5	0.9300
S1—C1	1.7422 (14)	C4—C3	1.398 (2)
O3—C8	1.3681 (16)	C4—H4	0.9300
O3—C7	1.3839 (16)	C13—C14	1.390 (2)
C9—C8	1.3694 (19)	C13—H13	0.9300
C9—C18	1.4561 (18)	C17—C16	1.394 (2)
C9—C10	1.5247 (18)	C17—H17	0.9300
C7—C11	1.3465 (19)	C19—O1	1.4516 (15)
C7—C6	1.4330 (18)	C19—C20	1.501 (2)
C12—C17	1.3879 (19)	C19—H19A	0.9700
C12—C13	1.3905 (19)	C19—H19B	0.9700
C12—C10	1.5293 (17)	C3—H3	0.9300
C10—C11	1.5022 (17)	C16—C15	1.383 (2)
C10—H10	0.9800	C16—H16	0.9300
C6—C5	1.402 (2)	C14—C15	1.386 (2)
C6—C1	1.404 (2)	C14—H14	0.9300
C18—O2	1.2253 (17)	C15—H15	0.9300
C18—O1	1.3448 (17)	C20—H20A	0.9600
C8—N1	1.3421 (18)	C20—H20B	0.9600
C1—C2	1.4000 (18)	C20—H20C	0.9600
C2—C3	1.377 (2)	N1—H1A	0.871 (19)
C2—H2	0.9300	N1—H1B	0.838 (18)
C5—C4	1.386 (2)

C11—S1—C1	91.31 (7)	C5—C4—C3	120.89 (14)
C8—O3—C7	116.29 (10)	C5—C4—H4	119.6
C8—C9—C18	117.89 (12)	C3—C4—H4	119.6
C8—C9—C10	123.22 (11)	C14—C13—C12	120.55 (13)
C18—C9—C10	118.65 (12)	C14—C13—H13	119.7
C11—C7—O3	123.83 (12)	C12—C13—H13	119.7
C11—C7—C6	115.61 (12)	C12—C17—C16	120.65 (13)
O3—C7—C6	120.49 (12)	C12—C17—H17	119.7
C17—C12—C13	118.85 (12)	C16—C17—H17	119.7
C17—C12—C10	119.85 (12)	O1—C19—C20	107.10 (12)
C13—C12—C10	121.19 (12)	O1—C19—H19A	110.3
C11—C10—C9	107.45 (11)	C20—C19—H19A	110.3
C11—C10—C12	110.46 (10)	O1—C19—H19B	110.3
C9—C10—C12	115.47 (10)	C20—C19—H19B	110.3
C11—C10—H10	107.7	H19A—C19—H19B	108.5
C9—C10—H10	107.7	C2—C3—C4	121.53 (13)
C12—C10—H10	107.7	C2—C3—H3	119.2
C7—C11—C10	124.58 (12)	C4—C3—H3	119.2
C7—C11—S1	111.31 (10)	C15—C16—C17	120.08 (14)
C10—C11—S1	124.10 (10)	C15—C16—H16	120.0
C5—C6—C1	119.86 (12)	C17—C16—H16	120.0
C5—C6—C7	130.52 (13)	C15—C14—C13	120.20 (13)
C1—C6—C7	109.59 (12)	C15—C14—H14	119.9
O2—C18—O1	121.79 (12)	C13—C14—H14	119.9
O2—C18—C9	126.25 (13)	C16—C15—C14	119.65 (13)
O1—C18—C9	111.95 (11)	C16—C15—H15	120.2
N1—C8—O3	109.09 (12)	C14—C15—H15	120.2
N1—C8—C9	127.01 (13)	C19—C20—H20A	109.5
O3—C8—C9	123.90 (12)	C19—C20—H20B	109.5
C2—C1—C6	121.28 (13)	H20A—C20—H20B	109.5
C2—C1—S1	126.56 (12)	C19—C20—H20C	109.5
C6—C1—S1	112.16 (10)	H20A—C20—H20C	109.5
C3—C2—C1	117.90 (14)	H20B—C20—H20C	109.5
C3—C2—H2	121.1	C18—O1—C19	115.69 (11)
C1—C2—H2	121.1	C8—N1—H1A	119.0 (11)
C4—C5—C6	118.54 (14)	C8—N1—H1B	119.6 (13)
C4—C5—H5	120.7	H1A—N1—H1B	120.2 (17)
C6—C5—H5	120.7

Hydrogen-bond geometry (Å, º) top

Cg1 is the centroid of the thiophene ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2ⁱ	0.838 (19)	2.285 (19)	2.9143 (16)	132.1 (15)
C10—H10···N1ⁱⁱ	0.98	2.57	3.5189 (17)	164
C15—H15···Cg1ⁱⁱⁱ	0.93	2.95	3.7493 (15)	145

Symmetry codes: (i) −x, −y+1, −z; (ii) x, y+1, z; (iii) x+1, y, z.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₇NO₃S
M_r	351.41
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	8.6612 (3), 5.9156 (2), 32.3008 (10)
β (°)	94.962 (2)
V (Å³)	1648.77 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.22
Crystal size (mm)	0.25 × 0.14 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD detector diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	21683, 3608, 3189
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.086, 1.04
No. of reflections	3608
No. of parameters	233
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.30, −0.22

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

Cg1 is the centroid of the thiophene ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O2ⁱ	0.838 (19)	2.285 (19)	2.9143 (16)	132.1 (15)
C10—H10···N1ⁱⁱ	0.98	2.57	3.5189 (17)	164.00
C15—H15···Cg1ⁱⁱⁱ	0.93	2.95	3.7493 (15)	145

Symmetry codes: (i) −x, −y+1, −z; (ii) x, y+1, z; (iii) x+1, y, z.

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

References

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Volume 67| Part 8| August 2011| Page o2106

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