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Crystals of the title compound, C14H11NO6, were obtained by the reaction of benzyl 2,6-dihydroxy­benzoate with nitric acid and crystallization of the product from ethyl acetate. In the mol­ecule, the nitro group is essentially coplanar with the attached benzene ring [O—N—C—C = 176.75 (11)°], indicating conjugation with the π-electron system. The benzyloxy group of the ester group is cis with respect to the 2-hydroxy group. The crystal structure is stabilized by intra- and inter­molecular hydrogen bonds. The 2-hydroxy group forms an intra­molecular hydrogen bond with the nitro group, and the 6-hydroxy group forms an intra­molecular hydrogen bond with the ester carbonyl function. In addition, there is inter­molecular hydrogen bonding between the 2-hydroxy group of one mol­ecule and the O atom of the 6-hydroxy group of another mol­ecule.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028541/lh2412sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028541/lh2412Isup2.hkl
Contains datablock I

CCDC reference: 654968

Key indicators

  • Single-crystal X-ray study
  • T = 90 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.041
  • wR factor = 0.114
  • Data-to-parameter ratio = 14.5

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT430_ALERT_2_B Short Inter D...A Contact O1 .. O1 .. 2.75 Ang.
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT230_ALERT_2_C Hirshfeld Test Diff for O1 - N1 .. 5.26 su
0 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 2 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

Phenolic acids are widely distributed in plants and they have been the subject of a great number of chemical, biological, agricultural, and medicinal studies (Herrmann, 1989). Hydroxybenzoic acids occur in food plants as esters or glycosides conjugated with other natural compounds such as flavonoids, alcohols, hydroxfatty acids, sterols, and glucosides. The alkyl esters of p-hydroxybenzoic acids are used extensively in the preservation of pharmaceuticals, because they are relatively nonirritating and nontoxic and offer good antimicrobial coverage. 2,6-Dihydroxybenzoic acid derivatives are known to exhibit anthelmintic activity, especially the 3-nitro analogue (Rushcig et al., 1973). In view of the biological activity associated with hydroxybenzoic acids, we have undertaken the synthesis of benzyl 2,6-dihydroxy-3-nitrobenzoate. In order to confirm the position of attachment of nitro group on the phenyl ring and to obtain more detailed information on the structural conformation of the molecule, its X-ray structure determination has been carried out.

X-ray crystallography confirmed the molecular structure and atom connectivity as illustrated in Fig. 1. In the title molecule the nitro group shows normal geometrical parameters. The torsion angles [O1—N1—C1—C6 = -176.75 (11) and O2—N1—C1—C2 = -177.50 (11) Å] indicate that there is not much deviation of nitro group plane from the plane of phenyl ring, facilitating conjugation with π electrons of the phenyl ring. Furthermore,the observed length of the N1—C1 bond [1.4329 (16) Å] is shorter than the theoretical length for a Car—NO2 bond of [1.468 (14) Å; Allen et al., 1987], which indicates the formation of a conjugated π-electron system along this bond. There is an asymmetry of the exocyclic angles at C1, C2, C3, C4, and C9 atoms.

The mode of packing of the title compound along the b direction is illustrated in Fig. 2. In addition to O—H···O intra and intermolecular hydrogen bonding and C—H···O interactions contribute to the stabilization of the crystal structure.

Related literature top

For related literature, see: Herrmann (1989); Rushcig et al. (1973); Wilson (1992).

Experimental top

The title compound was prepared by nitration of benzyl 2,6-dihydroxybenzoate and recrystallization of the resultant product from ethyl acetate afforded pale yellow coloured crystals. 1H NMR (DMSO-d6, p.p.m.): δ 5.31 (s, 2H), 6.57 (d, 1H), 7.32–7.44 (m, 5H), 8.03 (d, 1H), 10.95(s, 1H), 11.70 (s, 1H).

Refinement top

H atoms were found in difference Fourier maps and subsequently placed in idealized positions with constrained C—H distances of 0.95 Å (Car—H), 0.99 Å (CH2) and 0.84 Å (O—H). Uiso(H) values were set to 1.5Ueq(OH only) or 1.2eq of the attached atom.

Structure description top

Phenolic acids are widely distributed in plants and they have been the subject of a great number of chemical, biological, agricultural, and medicinal studies (Herrmann, 1989). Hydroxybenzoic acids occur in food plants as esters or glycosides conjugated with other natural compounds such as flavonoids, alcohols, hydroxfatty acids, sterols, and glucosides. The alkyl esters of p-hydroxybenzoic acids are used extensively in the preservation of pharmaceuticals, because they are relatively nonirritating and nontoxic and offer good antimicrobial coverage. 2,6-Dihydroxybenzoic acid derivatives are known to exhibit anthelmintic activity, especially the 3-nitro analogue (Rushcig et al., 1973). In view of the biological activity associated with hydroxybenzoic acids, we have undertaken the synthesis of benzyl 2,6-dihydroxy-3-nitrobenzoate. In order to confirm the position of attachment of nitro group on the phenyl ring and to obtain more detailed information on the structural conformation of the molecule, its X-ray structure determination has been carried out.

X-ray crystallography confirmed the molecular structure and atom connectivity as illustrated in Fig. 1. In the title molecule the nitro group shows normal geometrical parameters. The torsion angles [O1—N1—C1—C6 = -176.75 (11) and O2—N1—C1—C2 = -177.50 (11) Å] indicate that there is not much deviation of nitro group plane from the plane of phenyl ring, facilitating conjugation with π electrons of the phenyl ring. Furthermore,the observed length of the N1—C1 bond [1.4329 (16) Å] is shorter than the theoretical length for a Car—NO2 bond of [1.468 (14) Å; Allen et al., 1987], which indicates the formation of a conjugated π-electron system along this bond. There is an asymmetry of the exocyclic angles at C1, C2, C3, C4, and C9 atoms.

The mode of packing of the title compound along the b direction is illustrated in Fig. 2. In addition to O—H···O intra and intermolecular hydrogen bonding and C—H···O interactions contribute to the stabilization of the crystal structure.

For related literature, see: Herrmann (1989); Rushcig et al. (1973); Wilson (1992).

Computing details top

Data collection: COLLECT (Nonius, 1999); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Sheldrick, 1995); software used to prepare material for publication: SHELXL97 and local procedures.

Figures top
[Figure 1] Fig. 1. A view of the title molecule, with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. The packing diagram of the title compound, viewed down the b axis; showing the hydrogen-bonding interactions (dashed lines).
Benzyl 2,6-dihydroxy-3-nitrobenzoate top
Crystal data top
C14H11NO6F(000) = 600
Mr = 289.24Dx = 1.563 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3037 reflections
a = 10.0050 (3) Åθ = 1.0–27.5°
b = 6.1633 (2) ŵ = 0.12 mm1
c = 20.1048 (6) ÅT = 90 K
β = 97.5817 (12)°Cut plate, pale yellow
V = 1228.90 (7) Å30.30 × 0.25 × 0.08 mm
Z = 4
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
2791 independent reflections
Radiation source: fine-focus sealed tube2280 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.017
Detector resolution: 18 pixels mm-1θmax = 27.5°, θmin = 2.1°
ω scans at fixed χ = 55°h = 1212
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor, 1997)
k = 77
Tmin = 0.964, Tmax = 0.990l = 2625
5320 measured reflections
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)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.114H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0656P)2 + 0.3636P]
where P = (Fo2 + 2Fc2)/3
2791 reflections(Δ/σ)max < 0.001
192 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C14H11NO6V = 1228.90 (7) Å3
Mr = 289.24Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.0050 (3) ŵ = 0.12 mm1
b = 6.1633 (2) ÅT = 90 K
c = 20.1048 (6) Å0.30 × 0.25 × 0.08 mm
β = 97.5817 (12)°
Data collection top
Bruker Nonius KappaCCD area-detector
diffractometer
2791 independent reflections
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor, 1997)
2280 reflections with I > 2σ(I)
Tmin = 0.964, Tmax = 0.990Rint = 0.017
5320 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0410 restraints
wR(F2) = 0.114H-atom parameters constrained
S = 1.03Δρmax = 0.29 e Å3
2791 reflectionsΔρmin = 0.27 e Å3
192 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
N10.10725 (11)0.29419 (18)0.39249 (5)0.0213 (2)
O10.06977 (9)0.40479 (15)0.44407 (4)0.0240 (2)
O20.20301 (10)0.35119 (16)0.35140 (5)0.0287 (2)
O30.12549 (9)0.14652 (14)0.47955 (4)0.0217 (2)
H30.07730.25690.48240.033*
O40.13652 (10)0.48223 (15)0.34164 (5)0.0245 (2)
H40.20180.51270.37080.037*
O50.30779 (9)0.43345 (15)0.44313 (5)0.0252 (2)
O60.31031 (9)0.13490 (15)0.50629 (4)0.0209 (2)
C10.03792 (12)0.0967 (2)0.38146 (6)0.0194 (3)
C20.07555 (12)0.0302 (2)0.42602 (6)0.0180 (3)
C30.13804 (12)0.1685 (2)0.41310 (6)0.0186 (3)
C40.08403 (13)0.2913 (2)0.35642 (6)0.0202 (3)
C50.02761 (13)0.2183 (2)0.31257 (6)0.0227 (3)
H50.06130.30180.27430.027*
C60.08734 (13)0.0270 (2)0.32527 (6)0.0218 (3)
H60.16310.02290.29580.026*
C70.25843 (13)0.2571 (2)0.45507 (6)0.0197 (3)
C80.43003 (13)0.2209 (2)0.54614 (6)0.0220 (3)
H8A0.40990.36320.56540.026*
H8B0.50270.24130.51770.026*
C90.47396 (12)0.0615 (2)0.60144 (6)0.0198 (3)
C100.40299 (13)0.1265 (2)0.61159 (6)0.0232 (3)
H100.32240.15930.58280.028*
C110.44938 (14)0.2668 (2)0.66366 (6)0.0256 (3)
H110.40000.39490.67030.031*
C120.56721 (14)0.2217 (2)0.70606 (6)0.0245 (3)
H120.59840.31790.74160.029*
C130.63878 (13)0.0346 (2)0.69588 (7)0.0251 (3)
H130.71980.00260.72440.030*
C140.59223 (13)0.1064 (2)0.64395 (6)0.0246 (3)
H140.64160.23450.63740.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0200 (5)0.0208 (6)0.0230 (5)0.0004 (4)0.0030 (4)0.0026 (4)
O10.0264 (5)0.0213 (5)0.0240 (5)0.0030 (4)0.0022 (4)0.0032 (4)
O20.0254 (5)0.0280 (5)0.0306 (5)0.0072 (4)0.0043 (4)0.0016 (4)
O30.0225 (5)0.0179 (5)0.0237 (4)0.0032 (4)0.0009 (4)0.0039 (4)
O40.0250 (5)0.0206 (5)0.0271 (5)0.0031 (4)0.0005 (4)0.0054 (4)
O50.0258 (5)0.0209 (5)0.0282 (5)0.0054 (4)0.0004 (4)0.0037 (4)
O60.0200 (5)0.0199 (5)0.0217 (4)0.0028 (3)0.0021 (3)0.0014 (4)
C10.0193 (6)0.0175 (6)0.0217 (6)0.0001 (5)0.0043 (5)0.0019 (5)
C20.0184 (6)0.0180 (6)0.0178 (6)0.0027 (5)0.0031 (4)0.0011 (5)
C30.0178 (6)0.0186 (6)0.0197 (6)0.0001 (5)0.0030 (5)0.0006 (5)
C40.0205 (6)0.0184 (6)0.0223 (6)0.0017 (5)0.0053 (5)0.0006 (5)
C50.0229 (6)0.0237 (7)0.0210 (6)0.0022 (5)0.0010 (5)0.0025 (5)
C60.0195 (6)0.0245 (7)0.0208 (6)0.0013 (5)0.0009 (5)0.0024 (5)
C70.0205 (6)0.0189 (6)0.0201 (6)0.0014 (5)0.0040 (5)0.0003 (5)
C80.0202 (6)0.0221 (6)0.0229 (6)0.0044 (5)0.0005 (5)0.0007 (5)
C90.0188 (6)0.0220 (7)0.0189 (6)0.0005 (5)0.0031 (5)0.0023 (5)
C100.0212 (6)0.0243 (7)0.0233 (6)0.0039 (5)0.0002 (5)0.0015 (5)
C110.0274 (7)0.0232 (7)0.0257 (7)0.0043 (5)0.0017 (5)0.0007 (5)
C120.0246 (7)0.0268 (7)0.0218 (6)0.0028 (5)0.0015 (5)0.0019 (5)
C130.0182 (6)0.0334 (8)0.0232 (6)0.0016 (5)0.0001 (5)0.0013 (5)
C140.0212 (6)0.0279 (7)0.0243 (6)0.0060 (5)0.0018 (5)0.0003 (5)
Geometric parameters (Å, º) top
N1—O21.2308 (14)C5—H50.9500
N1—O11.2563 (14)C6—H60.9500
N1—C11.4329 (16)C8—C91.5051 (18)
O3—C21.3339 (15)C8—H8A0.9900
O3—H30.8400C8—H8B0.9900
O4—C41.3381 (15)C9—C101.3879 (18)
O4—H40.8400C9—C141.3929 (17)
O5—C71.2303 (16)C10—C111.3897 (19)
O6—C71.3253 (15)C10—H100.9500
O6—C81.4507 (15)C11—C121.3887 (18)
C1—C61.3977 (18)C11—H110.9500
C1—C21.4109 (17)C12—C131.387 (2)
C2—C31.4147 (18)C12—H120.9500
C3—C41.4144 (17)C13—C141.3904 (19)
C3—C71.4809 (17)C13—H130.9500
C4—C51.4026 (18)C14—H140.9500
C5—C61.3614 (19)
O2—N1—O1121.36 (11)O6—C7—C3116.02 (11)
O2—N1—C1119.24 (11)O6—C8—C9107.98 (10)
O1—N1—C1119.40 (10)O6—C8—H8A110.1
C2—O3—H3109.5C9—C8—H8A110.1
C4—O4—H4109.5O6—C8—H8B110.1
C7—O6—C8115.57 (10)C9—C8—H8B110.1
C6—C1—C2121.62 (12)H8A—C8—H8B108.4
C6—C1—N1117.47 (11)C10—C9—C14119.01 (12)
C2—C1—N1120.91 (11)C10—C9—C8123.25 (11)
O3—C2—C1122.74 (11)C14—C9—C8117.73 (11)
O3—C2—C3119.06 (11)C9—C10—C11120.26 (12)
C1—C2—C3118.20 (11)C9—C10—H10119.9
C4—C3—C2118.69 (11)C11—C10—H10119.9
C4—C3—C7117.21 (11)C12—C11—C10120.66 (13)
C2—C3—C7124.10 (11)C12—C11—H11119.7
O4—C4—C5116.47 (11)C10—C11—H11119.7
O4—C4—C3122.01 (11)C13—C12—C11119.27 (12)
C5—C4—C3121.52 (12)C13—C12—H12120.4
C6—C5—C4119.52 (12)C11—C12—H12120.4
C6—C5—H5120.2C12—C13—C14120.13 (12)
C4—C5—H5120.2C12—C13—H13119.9
C5—C6—C1120.44 (12)C14—C13—H13119.9
C5—C6—H6119.8C13—C14—C9120.67 (13)
C1—C6—H6119.8C13—C14—H14119.7
O5—C7—O6121.84 (11)C9—C14—H14119.7
O5—C7—C3122.14 (11)
O2—N1—C1—C62.73 (17)C2—C1—C6—C50.95 (19)
O1—N1—C1—C6176.75 (11)N1—C1—C6—C5178.81 (11)
O2—N1—C1—C2177.50 (11)C8—O6—C7—O51.20 (17)
O1—N1—C1—C23.01 (18)C8—O6—C7—C3178.63 (10)
C6—C1—C2—O3179.24 (11)C4—C3—C7—O52.46 (18)
N1—C1—C2—O31.01 (19)C2—C3—C7—O5178.09 (12)
C6—C1—C2—C30.95 (18)C4—C3—C7—O6177.38 (10)
N1—C1—C2—C3178.81 (11)C2—C3—C7—O62.08 (18)
O3—C2—C3—C4179.70 (11)C7—O6—C8—C9179.99 (10)
C1—C2—C3—C40.12 (17)O6—C8—C9—C103.07 (17)
O3—C2—C3—C70.85 (18)O6—C8—C9—C14176.59 (11)
C1—C2—C3—C7179.33 (11)C14—C9—C10—C110.3 (2)
C2—C3—C4—O4178.95 (11)C8—C9—C10—C11179.95 (12)
C7—C3—C4—O41.57 (18)C9—C10—C11—C120.2 (2)
C2—C3—C4—C51.20 (19)C10—C11—C12—C130.1 (2)
C7—C3—C4—C5178.28 (11)C11—C12—C13—C140.4 (2)
O4—C4—C5—C6178.91 (11)C12—C13—C14—C90.3 (2)
C3—C4—C5—C61.2 (2)C10—C9—C14—C130.1 (2)
C4—C5—C6—C10.14 (19)C8—C9—C14—C13179.75 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O10.841.812.5478 (12)145
O3—H3···N10.842.422.8703 (14)114
O3—H3···O1i0.842.563.2469 (13)139
O4—H4···O50.841.752.5034 (13)148
Symmetry code: (i) x, y1, z+1.

Experimental details

Crystal data
Chemical formulaC14H11NO6
Mr289.24
Crystal system, space groupMonoclinic, P21/c
Temperature (K)90
a, b, c (Å)10.0050 (3), 6.1633 (2), 20.1048 (6)
β (°) 97.5817 (12)
V3)1228.90 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.30 × 0.25 × 0.08
Data collection
DiffractometerBruker Nonius KappaCCD area-detector
Absorption correctionMulti-scan
(SCALEPACK; Otwinowski & Minor, 1997)
Tmin, Tmax0.964, 0.990
No. of measured, independent and
observed [I > 2σ(I)] reflections
5320, 2791, 2280
Rint0.017
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.041, 0.114, 1.03
No. of reflections2791
No. of parameters192
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.29, 0.27

Computer programs: COLLECT (Nonius, 1999), SCALEPACK (Otwinowski & Minor, 1997), DENZO-SMN (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP in SHELXTL (Sheldrick, 1995), SHELXL97 and local procedures.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O10.841.812.5478 (12)144.9
O3—H3···N10.842.422.8703 (14)114.4
O3—H3···O1i0.842.563.2469 (13)139.4
O4—H4···O50.841.752.5034 (13)147.9
Symmetry code: (i) x, y1, z+1.
 

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