(E)-2-(2-Nitro­prop-1-en­yl)furan

Abstract

Crystals of the title compound, C₇H₇NO₃, under Mo Kα radiation sublime in less than 1h at room temperature. However, it was possible to collect data at 100K. It crystallized as the E isomer only. A double-bond conjugation in the furan ring is extended to the nitro­alkenyl group. Mol­ecular associations were realized in the crystal through N⋯π [3.545 (2) Å] inter­actions involving the furan ring and C—H⋯O hydrogen bonds.

Related literature

For general background to (nitro-alken­yl)-furan compounds, see: Yan et al. (2008 ▶); Ono N. (2006 ▶); Vallejos et al. (2005 ▶); Negrín et al. (2003 ▶); Negrín et al. (2002 ▶), Estrada et al. (1999 ▶); Agafonov et al. (1991 ▶); Gruntfest et al. (1972 ▶). For related structures, see: Valerga et al. (2009 ▶); Martínez-Bescos et al. (2008 ▶); Novoa-de-Armas et al. (1997 ▶); Pomés et al. (1995 ▶).

Experimental

Crystal data

• C₇H₇NO₃

• M _r = 153.14

• Monoclinic,

• a = 7.1061 (14) Å

• b = 9.4394 (19) Å

• c = 10.743 (2) Å

• β = 101.86 (3)°

• V = 705.2 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.12 mm⁻¹

• T = 100 K

• 0.45 × 0.30 × 0.18 mm

Data collection

• Bruker SMART APEX diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.898, T _max = 1.000 (expected range = 0.880–0.980)

• 5648 measured reflections

• 1620 independent reflections

• 1497 reflections with I > 2σ(I)

• R _int = 0.032

Refinement

• R[F ² > 2σ(F ²)] = 0.049

• wR(F ²) = 0.130

• S = 1.07

• 1620 reflections

• 102 parameters

• H-atom parameters constrained

• Δρ_max = 0.29 e Å⁻³

• Δρ_min = −0.34 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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
C2—H2⋯O3i	0.95	2.47	3.3037 (19)	147
C5—H5⋯O3i	0.95	3.03	3.770 (2)	136
C4—H4⋯O2ii	0.95	2.65	3.2980 (19)	126
C4—H4⋯O3ii	0.95	2.58	3.516 (2)	170
C7—H7C⋯O2iii	0.98	2.70	3.310 (2)	121

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

supplementary crystallographic information

Comment

Some (nitro-alkenyl)-furan compounds show antibacterial and antifungal activities and were described and patented as drugs ingredients for veterinarian and agricultural purposes. We recently started the structural study of this group of furylnitroolefins. The title compound crystallized exclusively in its E configuration (Fig. 1). The conjugated system of double bonds in furan ring is extended to the alkenyl group being C2—C3 and C1—C5 bond lenghts 1.422 (2) and 1.431 (2) Å, significatively shorter than single C—C bonds. Distances N1—O2 = 1.232 (2) and N1—O3= 1.231 (2) indicate conjugation with a delocalized double bond. Alkenyl C5 and C6 sp² carbons are coplanar with the furan ring as shown by an angle of 3.9 (1)° between ring plane and C5 C6 C7 N1 plane. Crystal packing shows N···π interactions involving the furan ring: N···Cg (1/2-x, -1/2+y,1/2-z) distance is 3.545 (2) Å (Fig. 2) and CH···O hydrogen bonds (Table 1).

Experimental

2-(2-Nitro-propen-1-yl)-furan, also called UC-244, was obtained using the Knoevenagel's condensation method by reaction of furfural, an aromatic compound from acid hydrolysis of sugar cane residuals (straw, sawdust, etc.) and nitroethane in the presence of isobutylamine as a catalyst. To obtain a product with purity higher than 99% the method was optimized studying temperature, contact and reaction times as variables. The purification was achieved using activated coal and ethanol. The yellow crystals should be protected from the light and heating. ¹H NMR (CDCl₃) δ (ppm): 2.511 (3H, s, -CH₃), 6.533 (1H, dd, ²J = 3.6 Hz and ²J = 1.6 Hz, -O-CH=CH-CH=), 6.781 (1H, d, ²J = 3.6Hz, -O-CH=CH-CH=), 7.599 (1H, d, ²J = 1.6 Hz, -O-CH=CH-CH=), 7.775 (1H, s, HC=CMe) ¹³C{¹H} NMR (CDCl₃) δ (ppm): 13.656 (-C H₃), 112.688 (-O-CH=CH-CH=), 119.100 (-O-CH=CH-CH=), 120.346 (-C=C(Me)NO₂), 144.097 (-C=C(Me)NO₂), 146.104 (-O-CH=CH-CH=), 147.679 (C_ring-CH-C=C(Me)NO₂).

Refinement

All H atoms were positioned geometrically and treated as riding (C—H = 0.99Å for methylene and C—H = 0.93Å otherwise). U_iso(H) = 1.2 U_eq(C) of the carrier atom. In the absence of any significant anomalous scatters, the Friedel pairs were merged before final refinements.

Figures

Fig. 1.

ORTEP representation of I with the atom labelling scheme and displacement ellipsoids at the 50% probability level.

Fig. 2.

Packing diagram of E-2-(2-nitro-propen-1-yl)-furan.

Crystal data

C7H7NO3	F(000) = 320
Mr = 153.14	Dx = 1.442 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2619 reflections
a = 7.1061 (14) Å	θ = 2.9–27.6°
b = 9.4394 (19) Å	µ = 0.12 mm−1
c = 10.743 (2) Å	T = 100 K
β = 101.86 (3)°	Irregular, yellow
V = 705.2 (3) Å3	0.45 × 0.30 × 0.18 mm
Z = 4

Data collection

Bruker SMART APEX diffractometer	1620 independent reflections
Radiation source: fine-focus sealed tube	1497 reflections with I > 2σ(I)
graphite	Rint = 0.032
1700 ω scan frames, 0.3°, 10s	θmax = 27.6°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −9→8
Tmin = 0.898, Tmax = 1.000	k = −12→12
5648 measured reflections	l = −13→13

Refinement

Refinement on F2	0 constraints
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.049	w = 1/[σ2(Fo2) + (0.069P)2 + 0.2975P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.130	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.29 e Å−3
1620 reflections	Δρmin = −0.34 e Å−3
102 parameters	Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.012 (3)

Special details

Experimental. Refinement of F2 against unique set of 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 > 2sigma(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.

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 unique set of 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
O1	0.08533 (15)	0.64923 (11)	0.35499 (10)	0.0257 (3)
O2	0.22698 (17)	0.12565 (12)	0.41245 (11)	0.0328 (3)
O3	−0.00888 (16)	0.10699 (11)	0.25033 (11)	0.0311 (3)
N1	0.09873 (17)	0.17838 (13)	0.33088 (11)	0.0227 (3)
C1	0.19682 (19)	0.55649 (15)	0.43728 (13)	0.0200 (3)
C2	0.31539 (19)	0.62992 (15)	0.53073 (13)	0.0211 (3)
H2	0.4068	0.5911	0.5993	0.025*
C3	0.2760 (2)	0.77609 (16)	0.50590 (15)	0.0272 (4)
H3	0.3360	0.8539	0.5545	0.033*
C4	0.1374 (2)	0.78256 (15)	0.40026 (16)	0.0278 (4)
H4	0.0828	0.8679	0.3620	0.033*
C5	0.18569 (19)	0.40627 (15)	0.41909 (12)	0.0194 (3)
H5	0.2709	0.3514	0.4802	0.023*
C6	0.07004 (19)	0.33308 (14)	0.32658 (12)	0.0197 (3)
C7	−0.0833 (2)	0.38425 (16)	0.22071 (14)	0.0266 (3)
H7A	−0.1245	0.4791	0.2409	0.040*
H7B	−0.1932	0.3193	0.2092	0.040*
H7C	−0.0336	0.3881	0.1422	0.040*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0287 (6)	0.0186 (5)	0.0277 (5)	0.0010 (4)	0.0008 (4)	0.0023 (4)
O2	0.0399 (7)	0.0183 (5)	0.0339 (6)	0.0058 (5)	−0.0073 (5)	0.0003 (4)
O3	0.0372 (7)	0.0217 (6)	0.0304 (6)	−0.0050 (4)	−0.0023 (5)	−0.0073 (4)
N1	0.0263 (6)	0.0186 (6)	0.0223 (6)	−0.0007 (5)	0.0028 (5)	−0.0024 (5)
C1	0.0210 (7)	0.0172 (7)	0.0222 (7)	0.0015 (5)	0.0051 (5)	0.0019 (5)
C2	0.0197 (7)	0.0216 (7)	0.0217 (7)	−0.0002 (5)	0.0038 (5)	−0.0009 (5)
C3	0.0296 (8)	0.0210 (7)	0.0324 (8)	−0.0057 (6)	0.0100 (6)	−0.0069 (6)
C4	0.0321 (8)	0.0145 (7)	0.0383 (8)	0.0012 (6)	0.0105 (6)	0.0031 (6)
C5	0.0199 (7)	0.0173 (7)	0.0206 (6)	0.0013 (5)	0.0034 (5)	0.0010 (5)
C6	0.0217 (7)	0.0164 (6)	0.0211 (7)	0.0014 (5)	0.0047 (5)	0.0005 (5)
C7	0.0292 (8)	0.0254 (7)	0.0224 (7)	0.0037 (6)	−0.0014 (6)	−0.0020 (6)

Geometric parameters (Å, °)

O1—C4	1.3724 (18)	C3—C4	1.342 (2)
O1—C1	1.3739 (17)	C3—H3	0.9500
O2—N1	1.2320 (16)	C4—H4	0.9500
O3—N1	1.2311 (16)	C5—C6	1.3434 (19)
N1—C6	1.4739 (18)	C5—H5	0.9500
C1—C2	1.3602 (19)	C6—C7	1.4850 (19)
C1—C5	1.431 (2)	C7—H7A	0.9800
C2—C3	1.422 (2)	C7—H7B	0.9800
C2—H2	0.9500	C7—H7C	0.9800
C4—O1—C1	106.17 (12)	C3—C4—H4	124.6
O3—N1—O2	122.73 (12)	O1—C4—H4	124.6
O3—N1—C6	117.28 (11)	C6—C5—C1	128.22 (13)
O2—N1—C6	119.99 (11)	C6—C5—H5	115.9
C2—C1—O1	109.76 (13)	C1—C5—H5	115.9
C2—C1—C5	127.88 (13)	C5—C6—N1	115.26 (12)
O1—C1—C5	122.34 (12)	C5—C6—C7	129.82 (13)
C1—C2—C3	106.73 (13)	N1—C6—C7	114.92 (12)
C1—C2—H2	126.6	C6—C7—H7A	109.5
C3—C2—H2	126.6	C6—C7—H7B	109.5
C4—C3—C2	106.53 (13)	H7A—C7—H7B	109.5
C4—C3—H3	126.7	C6—C7—H7C	109.5
C2—C3—H3	126.7	H7A—C7—H7C	109.5
C3—C4—O1	110.81 (13)	H7B—C7—H7C	109.5
C4—O1—C1—C2	−0.25 (15)	O1—C1—C5—C6	−1.4 (2)
C4—O1—C1—C5	−178.62 (12)	C1—C5—C6—N1	177.53 (12)
O1—C1—C2—C3	0.10 (15)	C1—C5—C6—C7	−2.8 (2)
C5—C1—C2—C3	178.36 (13)	O3—N1—C6—C5	177.57 (12)
C1—C2—C3—C4	0.08 (16)	O2—N1—C6—C5	−2.79 (19)
C2—C3—C4—O1	−0.24 (17)	O3—N1—C6—C7	−2.15 (18)
C1—O1—C4—C3	0.31 (16)	O2—N1—C6—C7	177.49 (12)
C2—C1—C5—C6	−179.46 (13)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O3i	0.95	2.47	3.3037 (19)	147
C5—H5···O3i	0.95	3.03	3.770 (2)	136
C4—H4···O2ii	0.95	2.65	3.2980 (19)	126
C4—H4···O3ii	0.95	2.58	3.516 (2)	170
C7—H7C···O2iii	0.98	2.70	3.310 (2)	121

Symmetry codes: (i) x+1/2, −y+1/2, z+1/2; (ii) x, y+1, z; (iii) x−1/2, −y+1/2, z−1/2.