Ethyl 5-bromo­naphtho­[2,1-b]furan-2-carboxyl­ate

Abstract

In the title compound, C₁₅H₁₁BrO₃, the dihedral angle between the naphtho­furan ring system (r.m.s. deviation = 0.022 Å) and the side chain is 4.50 (2)°. In the crystal, short Br⋯Br [3.4435 (7) Å] contacts propagating along [010] in a zigzag manner and weak π–π inter­actions [shortest centroid–centroid separation = 3.573 (2) Å] directedalong [100] are observed.

Related literature  

For background to the biological activity of naphtho­furan derivatives, see: Vaidya et al. (2011 ▶).

Experimental  

Crystal data  

• C₁₅H₁₁BrO₃

• M _r = 319.15

• Monoclinic,

• a = 7.3108 (4) Å

• b = 11.1545 (6) Å

• c = 15.9752 (10) Å

• β = 100.921 (4)°

• V = 1279.16 (13) ų

• Z = 4

• Mo Kα radiation

• μ = 3.21 mm⁻¹

• T = 298 K

• 0.28 × 0.24 × 0.18 mm

Data collection  

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996) ▶ T _min = 0.467, T _max = 0.595

• 10028 measured reflections

• 2249 independent reflections

• 1699 reflections with I > 2σ(I)

• R _int = 0.037

Refinement  

• R[F ² > 2σ(F ²)] = 0.045

• wR(F ²) = 0.127

• S = 1.08

• 2249 reflections

• 172 parameters

• H-atom parameters constrained

• Δρ_max = 0.59 e Å⁻³

• Δρ_min = −0.54 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus; 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, 2012 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

As part of our ongoing studies of naphthofuran derivatives with possible biological activities (Vaidya et al., 2011), we now describe the structure of the title compound.

The title compound crystallizes in monoclinic crystal system with P2₁/c space group. The molecule is essentially planar with the dihedral angle between the mean planes defined by the naphthofuran moiety and the side chain is 4.50 (2)°, and the torsion angle of 179.81 (2)^o for C15—C14—O3—C13 shows that the ethyl group is in planar orientation with the naphthofuran ring. In contrast to this, an antiperiplanar orientation is observed between the ethyl group and the naphthofuran ring in ethylnaphtho[2,1-b]furan-2-carboxylate. In the crystal, weak Br···Br and π–π interaction between the rings C1—C6 and O1—C12 occur.

Experimental

To a solution of ethyl naphtho[2,1-b]furan- 2-carboxylate (0.1 mol) in glacial acetic acid (20 ml) was added a solution of bromine (0.1 mol) in acetic acid (20 ml) with stirring during 1 h at 10–20°C and the stirring was continued for 3 h. The reaction mixture was poured into ice-cold water and the solid obtained was filtered out. It was washed with water, dried and the product was recrystallized from ethanol solution as colourless prisms.

Refinement

The H atoms were positioned with idealized geometry using a riding model with C—H = 0.93 - 0.97 Å. The isotropic displacement parameters for all H atoms were set to 1.2 times of the U_eq of the parent atom (1.5 times of the U_eq of the parent atom for CH3).

Figures

Fig. 1.

Molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level.

Fig. 2.

Molecular packing of the title compound. Hydrogen bonds are shown as dashed lines.

Fig. 3.

Molecular packing of the title compound through π–π interactions are shown as dashed lines.

Crystal data

C15H11BrO3	prism
Mr = 319.15	Dx = 1.657 Mg m−3
Monoclinic, P21/c	Melting point: 402 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 7.3108 (4) Å	Cell parameters from 2249 reflections
b = 11.1545 (6) Å	θ = 2.2–25.0°
c = 15.9752 (10) Å	µ = 3.21 mm−1
β = 100.921 (4)°	T = 298 K
V = 1279.16 (13) Å3	Prism, colourless
Z = 4	0.28 × 0.24 × 0.18 mm
F(000) = 640

Data collection

Bruker APEXII CCD diffractometer	2249 independent reflections
Radiation source: fine-focus sealed tube	1699 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
Detector resolution: 0.95 pixels mm-1	θmax = 25.0°, θmin = 2.2°
phi and ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −12→13
Tmin = 0.467, Tmax = 0.595	l = −18→18
10028 measured reflections

Refinement

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127	H-atom parameters constrained
S = 1.08	w = 1/[σ2(Fo2) + (0.0587P)2 + 1.4776P] where P = (Fo2 + 2Fc2)/3
2249 reflections	(Δ/σ)max < 0.001
172 parameters	Δρmax = 0.59 e Å−3
0 restraints	Δρmin = −0.54 e Å−3
0 constraints

Special details

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
C15	−0.1065 (7)	−0.5565 (4)	0.3863 (3)	0.0671 (13)
H15A	−0.1556	−0.6243	0.3523	0.101*
H15B	−0.1951	−0.5306	0.4198	0.101*
H15C	0.0077	−0.5787	0.4233	0.101*
O1	0.1492 (4)	−0.0566 (2)	0.36398 (17)	0.0472 (7)
C1	0.3625 (5)	0.1416 (3)	0.5778 (3)	0.0429 (10)
C2	0.4360 (6)	0.2041 (4)	0.6518 (3)	0.0584 (12)
H2	0.4792	0.2821	0.6487	0.070*
C3	0.4446 (7)	0.1483 (5)	0.7312 (4)	0.0722 (15)
H3	0.4956	0.1924	0.7794	0.087*
C4	0.3872 (6)	0.0395 (4)	0.7436 (3)	0.0581 (12)
H4	0.3924	0.0076	0.7978	0.070*
C5	0.3127 (6)	−0.0296 (4)	0.6643 (3)	0.0552 (11)
H5	0.2734	−0.1083	0.6687	0.066*
C6	0.3009 (5)	0.0217 (3)	0.5838 (3)	0.0442 (9)
C7	0.2283 (5)	−0.0402 (3)	0.5065 (3)	0.0402 (9)
C8	0.2182 (5)	0.0167 (3)	0.4302 (3)	0.0420 (9)
C9	0.2729 (6)	0.1358 (3)	0.4210 (3)	0.0497 (10)
H9	0.2609	0.1722	0.3678	0.060*
C10	0.3435 (5)	0.1938 (3)	0.4934 (3)	0.0487 (11)
C11	0.1573 (5)	−0.1595 (3)	0.4862 (3)	0.0422 (9)
H11	0.1442	−0.2204	0.5244	0.051*
C12	0.1141 (5)	−0.1642 (3)	0.4006 (3)	0.0421 (9)
C13	0.0419 (6)	−0.2605 (4)	0.3405 (3)	0.0488 (10)
C14	−0.0706 (7)	−0.4583 (4)	0.3302 (3)	0.0616 (12)
H14A	0.0183	−0.4838	0.2958	0.074*
H14B	−0.1852	−0.4355	0.2923	0.074*
O2	0.0212 (6)	−0.2527 (3)	0.2649 (2)	0.0744 (10)
O3	0.0034 (4)	−0.3571 (2)	0.38317 (19)	0.0535 (8)
Br1	0.42767 (7)	0.35357 (4)	0.48343 (4)	0.0708 (2)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C15	0.088 (3)	0.045 (3)	0.069 (3)	−0.018 (2)	0.017 (3)	−0.009 (2)
O1	0.0569 (16)	0.0351 (15)	0.0501 (17)	−0.0048 (12)	0.0113 (13)	0.0043 (12)
C1	0.0341 (18)	0.034 (2)	0.063 (3)	0.0046 (16)	0.0143 (18)	−0.0021 (19)
C2	0.053 (3)	0.045 (3)	0.075 (3)	0.000 (2)	0.007 (2)	−0.014 (2)
C3	0.064 (3)	0.082 (4)	0.065 (4)	0.009 (3)	−0.003 (3)	−0.029 (3)
C4	0.046 (2)	0.059 (3)	0.069 (3)	0.007 (2)	0.009 (2)	0.030 (2)
C5	0.057 (2)	0.051 (3)	0.059 (3)	0.006 (2)	0.014 (2)	0.007 (2)
C6	0.0378 (19)	0.040 (2)	0.056 (3)	0.0072 (16)	0.0116 (18)	0.0010 (19)
C7	0.0356 (18)	0.033 (2)	0.052 (2)	0.0031 (15)	0.0074 (17)	−0.0044 (18)
C8	0.0411 (19)	0.034 (2)	0.053 (3)	0.0019 (16)	0.0152 (18)	0.0009 (19)
C9	0.053 (2)	0.037 (2)	0.063 (3)	0.0029 (18)	0.020 (2)	0.008 (2)
C10	0.040 (2)	0.0272 (19)	0.081 (3)	−0.0003 (16)	0.018 (2)	−0.001 (2)
C11	0.044 (2)	0.035 (2)	0.049 (3)	0.0037 (16)	0.0113 (18)	0.0072 (18)
C12	0.042 (2)	0.030 (2)	0.054 (3)	−0.0015 (16)	0.0098 (18)	0.0041 (17)
C13	0.051 (2)	0.044 (2)	0.052 (3)	−0.0052 (18)	0.010 (2)	0.000 (2)
C14	0.083 (3)	0.045 (2)	0.057 (3)	−0.015 (2)	0.014 (2)	−0.015 (2)
O2	0.114 (3)	0.063 (2)	0.046 (2)	−0.027 (2)	0.0132 (19)	−0.0010 (16)
O3	0.0742 (19)	0.0390 (16)	0.0463 (17)	−0.0151 (14)	0.0087 (15)	−0.0038 (13)
Br1	0.0814 (4)	0.0354 (3)	0.0987 (5)	−0.0111 (2)	0.0247 (3)	0.0021 (2)

Geometric parameters (Å, º)

C15—C14	1.470 (7)	C6—C7	1.426 (6)
C15—H15A	0.9600	C7—C8	1.363 (6)
C15—H15B	0.9600	C7—C11	1.443 (5)
C15—H15C	0.9600	C8—C9	1.403 (5)
O1—C8	1.357 (5)	C9—C10	1.341 (6)
O1—C12	1.380 (4)	C9—H9	0.9300
C1—C2	1.389 (6)	C10—Br1	1.902 (4)
C1—C6	1.420 (5)	C10—Br1	1.902 (4)
C1—C10	1.451 (6)	C11—C12	1.345 (6)
C2—C3	1.404 (8)	C11—H11	0.9300
C2—H2	0.9300	C12—C13	1.471 (6)
C3—C4	1.311 (7)	C13—O2	1.192 (5)
C3—H3	0.9300	C13—O3	1.333 (5)
C4—C5	1.495 (7)	C14—O3	1.452 (5)
C4—H4	0.9300	C14—H14A	0.9700
C5—C6	1.396 (6)	C14—H14B	0.9700
C5—H5	0.9300	Br1—Br1	0.0000
C14—C15—H15A	109.5	O1—C8—C9	124.0 (4)
C14—C15—H15B	109.5	C7—C8—C9	124.5 (4)
H15A—C15—H15B	109.5	C10—C9—C8	115.9 (4)
C14—C15—H15C	109.5	C10—C9—H9	122.1
H15A—C15—H15C	109.5	C8—C9—H9	122.1
H15B—C15—H15C	109.5	C9—C10—C1	124.2 (4)
C8—O1—C12	105.4 (3)	C9—C10—Br1	117.2 (3)
C2—C1—C6	119.5 (4)	C1—C10—Br1	118.5 (3)
C2—C1—C10	122.9 (4)	C9—C10—Br1	117.2 (3)
C6—C1—C10	117.6 (4)	C1—C10—Br1	118.5 (3)
C1—C2—C3	119.4 (4)	Br1—C10—Br1	0.00 (4)
C1—C2—H2	120.3	C12—C11—C7	105.7 (3)
C3—C2—H2	120.3	C12—C11—H11	127.2
C4—C3—C2	125.9 (5)	C7—C11—H11	127.2
C4—C3—H3	117.1	C11—C12—O1	111.7 (3)
C2—C3—H3	117.1	C11—C12—C13	132.7 (4)
C3—C4—C5	115.1 (5)	O1—C12—C13	115.6 (4)
C3—C4—H4	122.4	O2—C13—O3	125.4 (4)
C5—C4—H4	122.4	O2—C13—C12	124.7 (4)
C6—C5—C4	121.2 (4)	O3—C13—C12	110.0 (4)
C6—C5—H5	119.4	O3—C14—C15	108.3 (4)
C4—C5—H5	119.4	O3—C14—H14A	110.0
C5—C6—C1	118.9 (4)	C15—C14—H14A	110.0
C5—C6—C7	123.1 (4)	O3—C14—H14B	110.0
C1—C6—C7	118.0 (4)	C15—C14—H14B	110.0
C8—C7—C6	119.8 (4)	H14A—C14—H14B	108.4
C8—C7—C11	105.8 (4)	C13—O3—C14	114.9 (3)
C6—C7—C11	134.4 (4)	Br1—Br1—C10	0
O1—C8—C7	111.4 (3)