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ISSN: 2056-9890

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

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[Perlmutter, P. (1992). Conjugated Addition Reactions in Organic Synthesis, pp. 114-126. Oxford: Pergamon Press.]); Czarnocki et al. (2005[Czarnocki, Z., Siwicka, A. & Szawkało, J. (2005). Curr. Org. Synth. 2, 301-331.]); Rossiter & Swingle (1992[Rossiter, B. E. & Swingle, N. M. (1992). Chem. Rev. 92, 771-806.]).

[Scheme 1]

Experimental

Crystal data
  • C20H17NO3S

  • Mr = 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)

  • Rint = 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

  • Δρmax = 0.30 e Å−3

  • Δρmin = −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 DA 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[Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

The Michael addition of carbanions to the CC 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.

Refinement top

All H atoms bound to C atoms were treated as riding to their parent atoms [C—H distances are 0.93 Å for aromatic CH groups, 0.97 Å for methylene CH2 groups, 0.96 Å for the CH3 methyl group, and 0.98 Å for the CH methine group]. Isotropic displacement parameters are calculated as Uiso(H) = 1.5 Ueq(C20) for the methyl group and Uiso(H) = 1.2 Ueq(parent C) for other H atoms. The amine H atoms H1A and H1B were found in a difference map, and refined with N—H bond lengths restrained to 0.88 (2) Å and Uiso(H) = 1.2 Ueq(N1).

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
[Figure 1] 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.
[Figure 2] 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
C20H17NO3SF(000) = 736
Mr = 351.41Dx = 1.416 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 232 reflections
a = 8.6612 (3) Åθ = 2.6–25.3°
b = 5.9156 (2) ŵ = 0.22 mm1
c = 32.3008 (10) ÅT = 296 K
β = 94.962 (2)°Prism, colourless
V = 1648.77 (9) Å30.25 × 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 tubeRint = 0.031
Graphite monochromatorθmax = 27.0°, θmin = 2.4°
ω and ϕ scansh = 1111
21683 measured reflectionsk = 77
3608 independent reflectionsl = 4137
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0386P)2 + 0.7884P]
where P = (Fo2 + 2Fc2)/3
3608 reflections(Δ/σ)max = 0.001
233 parametersΔρmax = 0.30 e Å3
2 restraintsΔρmin = 0.22 e Å3
0 constraints
Crystal data top
C20H17NO3SV = 1648.77 (9) Å3
Mr = 351.41Z = 4
Monoclinic, P21/nMo Kα radiation
a = 8.6612 (3) ŵ = 0.22 mm1
b = 5.9156 (2) ÅT = 296 K
c = 32.3008 (10) Å0.25 × 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 reflectionsRint = 0.031
3608 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0342 restraints
wR(F2) = 0.086H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.30 e Å3
3608 reflectionsΔρmin = 0.22 e Å3
233 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
S10.18188 (4)1.17172 (6)0.191397 (10)0.02581 (10)
O30.03012 (11)0.62652 (16)0.13342 (3)0.0244 (2)
C90.15146 (15)0.8299 (2)0.08005 (4)0.0209 (3)
C70.07313 (15)0.8007 (2)0.16060 (4)0.0209 (3)
C120.39539 (14)1.0315 (2)0.11368 (4)0.0191 (3)
C100.21849 (14)1.0162 (2)0.10886 (4)0.0193 (3)
H100.17851.16100.09780.023*
C110.15652 (15)0.9814 (2)0.15042 (4)0.0206 (3)
C60.02270 (15)0.8029 (2)0.20170 (4)0.0219 (3)
C180.16810 (15)0.8490 (2)0.03571 (4)0.0233 (3)
C80.06481 (15)0.6545 (2)0.09321 (4)0.0212 (3)
C10.07339 (15)1.0023 (2)0.22215 (4)0.0233 (3)
C20.03563 (16)1.0502 (3)0.26251 (4)0.0280 (3)
H20.06921.18270.27590.034*
C50.06701 (16)0.6470 (3)0.22184 (4)0.0263 (3)
H50.10110.51400.20870.032*
C40.10381 (16)0.6953 (3)0.26180 (4)0.0300 (3)
H40.16330.59360.27560.036*
C130.48520 (16)0.8567 (2)0.13167 (4)0.0246 (3)
H130.43790.72360.13920.030*
C170.46835 (16)1.2279 (2)0.10227 (4)0.0240 (3)
H170.40971.34530.08990.029*
C190.26683 (17)1.0704 (3)0.01709 (4)0.0287 (3)
H19A0.16761.09400.03280.034*
H19B0.31590.93890.02820.034*
C30.05272 (17)0.8949 (3)0.28169 (4)0.0303 (3)
H30.07900.92340.30850.036*
C160.62864 (17)1.2511 (3)0.10919 (5)0.0294 (3)
H160.67641.38350.10150.035*
C140.64516 (16)0.8792 (3)0.13841 (4)0.0292 (3)
H140.70430.76080.15030.035*
C150.71678 (16)1.0774 (3)0.12754 (4)0.0305 (3)
H150.82361.09350.13260.037*
C200.36800 (19)1.2749 (3)0.01999 (5)0.0361 (4)
H20A0.31481.40590.01100.054*
H20B0.39141.29540.04830.054*
H20C0.46251.25420.00260.054*
O10.24544 (11)1.03714 (17)0.02657 (3)0.0257 (2)
O20.11868 (12)0.71560 (19)0.00872 (3)0.0319 (2)
N10.00146 (15)0.4847 (2)0.06999 (4)0.0279 (3)
H1A0.062 (2)0.392 (3)0.0809 (5)0.034*
H1B0.009 (2)0.484 (3)0.0443 (6)0.034*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.02830 (19)0.02802 (19)0.02170 (17)0.00438 (14)0.00562 (13)0.00647 (14)
O30.0311 (5)0.0234 (5)0.0187 (5)0.0041 (4)0.0023 (4)0.0009 (4)
C90.0206 (6)0.0245 (7)0.0173 (6)0.0016 (5)0.0005 (5)0.0016 (5)
C70.0192 (6)0.0240 (7)0.0191 (6)0.0016 (5)0.0001 (5)0.0022 (5)
C120.0204 (6)0.0240 (6)0.0130 (5)0.0008 (5)0.0021 (5)0.0034 (5)
C100.0193 (6)0.0209 (6)0.0176 (6)0.0024 (5)0.0005 (5)0.0004 (5)
C110.0187 (6)0.0243 (7)0.0187 (6)0.0019 (5)0.0009 (5)0.0026 (5)
C60.0179 (6)0.0284 (7)0.0194 (6)0.0054 (5)0.0003 (5)0.0005 (5)
C180.0218 (6)0.0272 (7)0.0206 (6)0.0023 (5)0.0000 (5)0.0018 (5)
C80.0211 (6)0.0233 (7)0.0185 (6)0.0040 (5)0.0016 (5)0.0009 (5)
C10.0192 (6)0.0297 (7)0.0210 (6)0.0042 (5)0.0015 (5)0.0004 (6)
C20.0274 (7)0.0355 (8)0.0209 (6)0.0068 (6)0.0016 (5)0.0035 (6)
C50.0233 (7)0.0315 (7)0.0241 (7)0.0005 (6)0.0011 (5)0.0038 (6)
C40.0240 (7)0.0422 (9)0.0243 (7)0.0034 (6)0.0043 (5)0.0094 (6)
C130.0254 (7)0.0256 (7)0.0227 (6)0.0008 (5)0.0007 (5)0.0017 (6)
C170.0252 (7)0.0249 (7)0.0222 (6)0.0017 (5)0.0034 (5)0.0021 (6)
C190.0335 (8)0.0369 (8)0.0161 (6)0.0048 (6)0.0034 (5)0.0020 (6)
C30.0263 (7)0.0460 (9)0.0191 (6)0.0104 (6)0.0047 (5)0.0023 (6)
C160.0266 (7)0.0333 (8)0.0292 (7)0.0055 (6)0.0073 (6)0.0016 (6)
C140.0246 (7)0.0341 (8)0.0282 (7)0.0072 (6)0.0015 (6)0.0021 (6)
C150.0192 (7)0.0442 (9)0.0283 (7)0.0003 (6)0.0026 (5)0.0021 (7)
C200.0381 (9)0.0423 (9)0.0289 (8)0.0019 (7)0.0082 (6)0.0084 (7)
O10.0322 (5)0.0294 (5)0.0157 (4)0.0024 (4)0.0027 (4)0.0003 (4)
O20.0390 (6)0.0359 (6)0.0206 (5)0.0061 (5)0.0010 (4)0.0076 (4)
N10.0353 (7)0.0262 (6)0.0219 (6)0.0057 (5)0.0001 (5)0.0029 (5)
Geometric parameters (Å, º) top
S1—C111.7371 (13)C5—H50.9300
S1—C11.7422 (14)C4—C31.398 (2)
O3—C81.3681 (16)C4—H40.9300
O3—C71.3839 (16)C13—C141.390 (2)
C9—C81.3694 (19)C13—H130.9300
C9—C181.4561 (18)C17—C161.394 (2)
C9—C101.5247 (18)C17—H170.9300
C7—C111.3465 (19)C19—O11.4516 (15)
C7—C61.4330 (18)C19—C201.501 (2)
C12—C171.3879 (19)C19—H19A0.9700
C12—C131.3905 (19)C19—H19B0.9700
C12—C101.5293 (17)C3—H30.9300
C10—C111.5022 (17)C16—C151.383 (2)
C10—H100.9800C16—H160.9300
C6—C51.402 (2)C14—C151.386 (2)
C6—C11.404 (2)C14—H140.9300
C18—O21.2253 (17)C15—H150.9300
C18—O11.3448 (17)C20—H20A0.9600
C8—N11.3421 (18)C20—H20B0.9600
C1—C21.4000 (18)C20—H20C0.9600
C2—C31.377 (2)N1—H1A0.871 (19)
C2—H20.9300N1—H1B0.838 (18)
C5—C41.386 (2)
C11—S1—C191.31 (7)C5—C4—C3120.89 (14)
C8—O3—C7116.29 (10)C5—C4—H4119.6
C8—C9—C18117.89 (12)C3—C4—H4119.6
C8—C9—C10123.22 (11)C14—C13—C12120.55 (13)
C18—C9—C10118.65 (12)C14—C13—H13119.7
C11—C7—O3123.83 (12)C12—C13—H13119.7
C11—C7—C6115.61 (12)C12—C17—C16120.65 (13)
O3—C7—C6120.49 (12)C12—C17—H17119.7
C17—C12—C13118.85 (12)C16—C17—H17119.7
C17—C12—C10119.85 (12)O1—C19—C20107.10 (12)
C13—C12—C10121.19 (12)O1—C19—H19A110.3
C11—C10—C9107.45 (11)C20—C19—H19A110.3
C11—C10—C12110.46 (10)O1—C19—H19B110.3
C9—C10—C12115.47 (10)C20—C19—H19B110.3
C11—C10—H10107.7H19A—C19—H19B108.5
C9—C10—H10107.7C2—C3—C4121.53 (13)
C12—C10—H10107.7C2—C3—H3119.2
C7—C11—C10124.58 (12)C4—C3—H3119.2
C7—C11—S1111.31 (10)C15—C16—C17120.08 (14)
C10—C11—S1124.10 (10)C15—C16—H16120.0
C5—C6—C1119.86 (12)C17—C16—H16120.0
C5—C6—C7130.52 (13)C15—C14—C13120.20 (13)
C1—C6—C7109.59 (12)C15—C14—H14119.9
O2—C18—O1121.79 (12)C13—C14—H14119.9
O2—C18—C9126.25 (13)C16—C15—C14119.65 (13)
O1—C18—C9111.95 (11)C16—C15—H15120.2
N1—C8—O3109.09 (12)C14—C15—H15120.2
N1—C8—C9127.01 (13)C19—C20—H20A109.5
O3—C8—C9123.90 (12)C19—C20—H20B109.5
C2—C1—C6121.28 (13)H20A—C20—H20B109.5
C2—C1—S1126.56 (12)C19—C20—H20C109.5
C6—C1—S1112.16 (10)H20A—C20—H20C109.5
C3—C2—C1117.90 (14)H20B—C20—H20C109.5
C3—C2—H2121.1C18—O1—C19115.69 (11)
C1—C2—H2121.1C8—N1—H1A119.0 (11)
C4—C5—C6118.54 (14)C8—N1—H1B119.6 (13)
C4—C5—H5120.7H1A—N1—H1B120.2 (17)
C6—C5—H5120.7
Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the thiophene ring.
D—H···AD—HH···AD···AD—H···A
N1—H1B···O2i0.838 (19)2.285 (19)2.9143 (16)132.1 (15)
C10—H10···N1ii0.982.573.5189 (17)164
C15—H15···Cg1iii0.932.953.7493 (15)145
Symmetry codes: (i) x, y+1, z; (ii) x, y+1, z; (iii) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC20H17NO3S
Mr351.41
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)8.6612 (3), 5.9156 (2), 32.3008 (10)
β (°) 94.962 (2)
V3)1648.77 (9)
Z4
Radiation typeMo Kα
µ (mm1)0.22
Crystal size (mm)0.25 × 0.14 × 0.12
Data collection
DiffractometerBruker APEXII CCD detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
21683, 3608, 3189
Rint0.031
(sin θ/λ)max1)0.639
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.086, 1.04
No. of reflections3608
No. of parameters233
No. of restraints2
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)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···AD—HH···AD···AD—H···A
N1—H1B···O2i0.838 (19)2.285 (19)2.9143 (16)132.1 (15)
C10—H10···N1ii0.982.573.5189 (17)164.00
C15—H15···Cg1iii0.932.953.7493 (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

First citationBruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationCzarnocki, Z., Siwicka, A. & Szawkało, J. (2005). Curr. Org. Synth. 2, 301–331.  Web of Science CrossRef CAS Google Scholar
First citationPerlmutter, P. (1992). Conjugated Addition Reactions in Organic Synthesis, pp. 114–126. Oxford: Pergamon Press.  Google Scholar
First citationRossiter, B. E. & Swingle, N. M. (1992). Chem. Rev. 92, 771–806.  CrossRef CAS Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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