Methyl 4-anilino-2′,5-dioxo-1′,2′-di­hydro-5H-spiro­[furan-2,3′-indole]-3-carboxyl­ate

Rajeswari Gangadharan; K Sethusankar; Selvarangam E Kiruthika; P T Perumal

doi:10.1107/S1600536813014967

. 2013 Jun 8;69(Pt 7):o1055. doi: 10.1107/S1600536813014967

Methyl 4-anilino-2′,5-dioxo-1′,2′-dihydro-5H-spiro[furan-2,3′-indole]-3-carboxylate

Rajeswari Gangadharan ^a, K Sethusankar ^b,^*, Selvarangam E Kiruthika ^c, P T Perumal ^c

PMCID: PMC3772486 PMID: 24046629

Abstract

In the title compound, C₁₉H₁₄N₂O₅, the spiro junction links an oxindole moeity and a furan ring, which subtend a dihedral angle of 83.49 (6)°. The molecular structure features an N—H⋯O hydrogen bond, which generates an S(6) ring motif. The crystal packing is governed by two N—H⋯O interactions, one of which generates a centrosymmetric R ₂ ²(14) dimer. The other N—H⋯O interaction along with a C—H⋯O hydrogen bond contributes to the formation of a C ₂ ²[R ₂ ²(9)] dimeric chain running along the b-axis direction.

Related literature

For applications of spiro oxindoles, see: Kornet & Thio (1976 ▶); Kobayashi et al. (1991 ▶). For applications of furans, see: Schoop et al. (2000 ▶). For puckering and asymmetry parameters, see: Cremer & Pople (1975 ▶). For a related structure, see: Gayathri et al. (2006 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₉H₁₄N₂O₅
M _r = 350.32
Monoclinic,
a = 12.1713 (6) Å
b = 13.6144 (7) Å
c = 10.9602 (6) Å
β = 114.813 (2)°
V = 1648.50 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 296 K
0.30 × 0.25 × 0.20 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.969, T _max = 0.979
20901 measured reflections
5167 independent reflections
3502 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.132
S = 1.00
5167 reflections
242 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813014967/rk2403sup1.cif

e-69-o1055-sup1.cif^{(20.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813014967/rk2403Isup2.hkl

e-69-o1055-Isup2.hkl^{(247.9KB, hkl)}

Click here for additional data file.^{(6.6KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813014967/rk2403Isup3.cml

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
N1—H1A⋯O5ⁱ	0.89 (2)	2.19 (2)	3.0268 (16)	157 (2)
N2—H2A⋯O1ⁱⁱ	0.89 (1)	2.19 (1)	2.9907 (17)	149 (1)
N2—H2A⋯O5	0.89 (1)	2.39 (2)	2.9691 (16)	123 (1)
C13—H13A⋯O1ⁱⁱⁱ	0.96	2.41	3.2999 (18)	153

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the data collection.

supplementary crystallographic information

Comment

Spiro compounds represent an important class of naturally occurring substances characterized by highly pronounced biological properties (Kobayashi et al., 1991). Among them the spiro oxindole is an important structural motif which finds wide applications as antimicrobial and antitumour agents and as inhibitors of the human NK1 receptor (Kornet & Thio, 1976). The construction of polyfunctionalized furans, spiro furans and furan fused cycloalkanes are important from the standpoint of synthesis of biologically active natural products such as aflatoxin, asteltoxin, monensin, panacene etc., (Schoop et al., 2000).

The bond lengths and angles in the title compound are within normal ranges except those at the spiro junction which reflects the presence of bulky subsituents. The dihedral angle between the five (C5/C6/N1/C7/C8) and six membered (C1–C6) rings in the indole group is 4.15 (8)°. The indole moeity is orthogonal to the furan ring as indicated by the dihedral angle of 83.49 (6)° between them.

The furan ring in the structure adopts a twisted conformation with a psuedo–twofold axis passing through the C8 atom and C9–C10 bond. The puckering parameters (Cremer & Pople, 1975) for the furan ring are q₂ = 0.0810 (14)Å, φ₂ = 310.9 (10)°. The benzene ring is bisectionally oriented to the furan ring, the dihedral angle between them being 52.80 (8)°. The title compound exihibits structural similarities with an already reported related structure (Gayathri et al., 2006.)

The molecular structure is stabilized by intramolecular N2—H2A···O5 bond which generates S(6) ring motif. Atom N2 acts as a donor to O1ⁱⁱ generating a centrosymmetric dimer with graph set descriptor of R²₂(14) (Bernstein et al., 1995). The bifurcated H bond at O1 facilitates the C13—H13···O1ⁱⁱⁱ bond, which together with a N1—H1(A)···O5ⁱ interaction forms a non–centrosymmetric R²₂(9) dimer. These non–centrosymmetric dimers aggregate to form C²₂[R²₂(9)] supramolecular chains running along the b axis. The symmetry codes for the interactions are: (i) 1-x, -1/2+y, 3/2-z; (ii) 1-x, 1-y, 2-z; (iii) 1-x, 1/2+y, 3/2-z.

Experimental

Isatin (1 mmol), aromatic amine (1 mmol), and dimethyl acetylene dicarboxylate (1 mmol) were stirred at room temperature in methanol in the presence of triethylamine (20 mol%) for 4 hrs to give the spirolactones which was filtered out and recrystallized from methanol to afford the pure product (85% yield) as yellow solid.