organic compounds
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
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
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Data collection
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Refinement
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Data collection: APEX2 (Bruker, 2005); cell 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
10.1107/S1600536811027152/bh2365sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811027152/bh2365Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536811027152/bh2365Isup3.cml
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.
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).
Data collection: APEX2 (Bruker, 2005); cell
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).C20H17NO3S | F(000) = 736 |
Mr = 351.41 | Dx = 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 |
Bruker APEXII CCD detector diffractometer | 3189 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 27.0°, θmin = 2.4° |
ω and ϕ scans | h = −11→11 |
21683 measured reflections | k = −7→7 |
3608 independent reflections | l = −41→37 |
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(Fo2) + (0.0386P)2 + 0.7884P] where P = (Fo2 + 2Fc2)/3 |
3608 reflections | (Δ/σ)max = 0.001 |
233 parameters | Δρmax = 0.30 e Å−3 |
2 restraints | Δρmin = −0.22 e Å−3 |
0 constraints |
C20H17NO3S | V = 1648.77 (9) Å3 |
Mr = 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)° |
Bruker APEXII CCD detector diffractometer | 3189 reflections with I > 2σ(I) |
21683 measured reflections | Rint = 0.031 |
3608 independent reflections |
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 | Δρmax = 0.30 e Å−3 |
3608 reflections | Δρmin = −0.22 e Å−3 |
233 parameters |
x | y | z | Uiso*/Ueq | ||
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* |
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) |
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 |
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 |
Mr | 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 |
Rint | 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 |
Δρmax, Δρmin (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).
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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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).