organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

N-(3,4-Di­fluoro­phen­yl)-2-(3,4-di­meth­oxy­phen­yl)acetamide

aDepartment of Chemistry, Chungnam National University, Daejeon 305-764, Republic of Korea, and bDepartment of Food Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea
*Correspondence e-mail: skkang@cnu.ac.kr

(Received 9 January 2008; accepted 1 February 2008; online 6 February 2008)

In the title amide, C16H15F2NO3, the dihedral angle between the benzene rings is 53.7 (1)°. Mol­ecules are linked in the crystal structure by an inter­molecular N—H⋯O hydrogen bond involving N—H and C=O functionalities of the amide group. A one-dimensional network is thus formed along the [001] direction. No significant inter­chain contacts are observed.

Related literature

For general background, see: Maeda et al. (1991[Maeda, K. & Fukuda, M. (1991). J. Soc. Cosmet. Chem. 42, 361-368.]); Dawley et al. (1993[Dawley, R. M. & Flurkey, W. H. (1993). J. Food Sci. 58, 609-610.]); Nerya et al. (2003[Nerya, O., Vaya, J., Musa, R., Izrael, S., Ben-Arie, R. & Tamir, S. (2003). J. Agric. Food Chem. 51, 1201-1207.]); Lee et al. (2007[Lee, C. W., Son, E.-M., Kim, H. S., Xu, P., Batmunkh, T., Lee, B. J. & Koo, K. A. (2007). Bioorg. Med. Chem. Lett. 17, 5462-5464.]); Ha et al. (2007[Ha, Y. M., Chung, S. W., Song, S. H. & Lee, H. J. (2007). Biol. Pharm. Bull. 30, 1711-1715.]); Hong et al. (2008[Hong, W. K., Heo, J. Y., Han, B. H., Sung, C. K. & Kang, S. K. (2008). Acta Cryst. E64, o49.]); Yan et al. (2007[Yan, H. L., Lin, T. & Zheng, T. W. (2007). J. Enzyme Inhib. Med. Chem. 22, 433-438.]).

[Scheme 1]

Experimental

Crystal data
  • C16H15F2NO3

  • Mr = 307.29

  • Monoclinic, P 21 /c

  • a = 8.6440 (11) Å

  • b = 18.867 (6) Å

  • c = 9.4827 (13) Å

  • β = 111.019 (11)°

  • V = 1443.6 (5) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 295 (2) K

  • 0.26 × 0.26 × 0.23 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: none

  • 2855 measured reflections

  • 2689 independent reflections

  • 1089 reflections with I > 2σ(I)

  • Rint = 0.050

  • 3 standard reflections every 400 reflections intensity decay: 3%

Refinement
  • R[F2 > 2σ(F2)] = 0.076

  • wR(F2) = 0.161

  • S = 0.99

  • 2689 reflections

  • 203 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.19 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N7—H7⋯O9i 0.89 (5) 1.98 (5) 2.846 (5) 163 (5)
Symmetry code: (i) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}].

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994[Enraf-Nonius (1994). CAD-4 EXPRESS. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Tyrosinase is the key enzyme (Ha et al., 2007) that converts tyrosine to melanin, and its inhibitors are the target molecules to develop and research anti-pigmentation agents for application to skin. The melanin formation is also accelerated by exposure under sunlight, especially U.V. (Ha et al., 2007; Yan et al., 2007). Therefore, treatments using potent inhibitory agents on tyrosinase and melanin formation may be cosmetically useful. Most of the whitening agents (Maeda et al., 1991; Dawley et al., 1993; Nerya et al., 2003) contain hydroxyl (Hong et al., 2008; Lee et al., 2007), aromatic, alkene, carbonyl, and ether groups in their structure, and act as a specific functional group to make the skin white by inhibiting the production of melanin.

During our work on developing potent whiting agents, in order to prevent the inadequacies of current whitening agents (poor skin penetration and toxicity) and maximize the inhibitory effects of melanin creation, we synthesized the title compound, (I), via a general chemical reaction, and studied its X-ray crystal structure.

The 3,4-dimethoxyphenyl moiety and 3,4-difluoroaniline group are essentially planar, with a mean deviation of 0.005 and 0.006 Å, respectively, from the corresponding least-squares planes. The dihedral angle between the benzene rings is 53.7 (1)°. The intermolecular N7—H7···O9i (symmetry code: (i) x, -y + 3/2, z - 1/2) hydrogen bond (involving the H atom of the amine and O atom of carbonyl) allows to form an extensive one-dimensional network along the c-axis, which stabilizes the crystal structure.

Related literature top

For general background see: Maeda et al. (1991); Dawley et al. (1993); Nerya et al. (2003); Lee et al. (2007); Ha et al. (2007); Hong et al. (2008); Yan et al. (2007).

Experimental top

3,4-Difluoroaniline and 3,4-dimethoxy phenyl acetyl chloride were purchased from Sigma Chemicals Co. Solvents used for organic synthesis were distilled before use. All other chemicals and solvents were of analytical grade and used without further purification. The title compound was prepared from the reaction of 3,4-difluoroaniline (1 mmol) and 3,4-dimethoxy phenyl acetyl chloride (1.2 mmol) by simple substitution (nucleophilic addition-elimination on carbonyl C atom) in THF. Removal of solvent gave a white solid. The solid was purified by column chromatography on silica gel (2:1 hexane/ethyl acetate) to give the title compound (92% yield). Colourless crystals (m.p. 393 K) were obtained by slow evaporation of an ethyl acetate solution at 298 K.

Refinement top

Although diffraction data were collected using optimized parameters, a poor quality pattern resulted, which is reflected in the high final residuals. Atom H7 of the NH group was located in a differnce map and refined freely. Other H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93–0.97 Å, and with Uiso(H) = 1.2Ueq(carrier C) for aromatic and CH2 groups, and 1.5Ueq(carrier C) for methyl H atoms.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atom-numbering scheme and 30% probability ellipsoids.
N-(3,4-Difluorophenyl)-2-(3,4-dimethoxyphenyl)acetamide top
Crystal data top
C16H15F2NO3F(000) = 640
Mr = 307.29Dx = 1.414 Mg m3
Monoclinic, P21/cMelting point: 393 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 8.6440 (11) ÅCell parameters from 25 reflections
b = 18.867 (6) Åθ = 10.0–13.5°
c = 9.4827 (13) ŵ = 0.12 mm1
β = 111.019 (11)°T = 295 K
V = 1443.6 (5) Å3Block, colourless
Z = 40.26 × 0.26 × 0.23 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
θmax = 25.5°, θmin = 2.2°
non–profiled ω/2θ scansh = 109
2855 measured reflectionsk = 022
2689 independent reflectionsl = 011
1089 reflections with I > 2σ(I)3 standard reflections every 400 reflections
Rint = 0.050 intensity decay: 3%
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.076 w = 1/[σ2(Fo2) + (0.0403P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.161(Δ/σ)max < 0.001
S = 1.00Δρmax = 0.19 e Å3
2689 reflectionsΔρmin = 0.19 e Å3
203 parameters
Crystal data top
C16H15F2NO3V = 1443.6 (5) Å3
Mr = 307.29Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.6440 (11) ŵ = 0.12 mm1
b = 18.867 (6) ÅT = 295 K
c = 9.4827 (13) Å0.26 × 0.26 × 0.23 mm
β = 111.019 (11)°
Data collection top
Enraf–Nonius CAD-4
diffractometer
Rint = 0.050
2855 measured reflections3 standard reflections every 400 reflections
2689 independent reflections intensity decay: 3%
1089 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0760 restraints
wR(F2) = 0.161H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.19 e Å3
2689 reflectionsΔρmin = 0.19 e Å3
203 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.1632 (6)0.6519 (2)0.2444 (5)0.0423 (12)
C20.0544 (6)0.6516 (3)0.3939 (5)0.0492 (13)
H20.05780.68710.46060.059*
C30.0570 (7)0.5976 (3)0.4396 (6)0.0581 (15)
C40.0637 (7)0.5447 (3)0.3452 (6)0.0593 (15)
C50.0438 (7)0.5443 (3)0.1995 (6)0.0671 (17)
H50.04070.50790.13460.081*
C60.1575 (6)0.5985 (3)0.1487 (5)0.0531 (14)
H60.23060.59880.04890.064*
F10.1663 (4)0.59760 (17)0.5842 (3)0.0941 (12)
F20.1777 (4)0.49215 (17)0.3968 (4)0.0917 (12)
N70.2760 (5)0.7098 (2)0.2001 (4)0.0446 (11)
H70.304 (6)0.729 (3)0.273 (5)0.08 (2)*
C80.3307 (6)0.7408 (3)0.0639 (5)0.0418 (12)
O90.2978 (4)0.71902 (17)0.0431 (3)0.0608 (11)
C100.4341 (6)0.8066 (3)0.0549 (5)0.0566 (15)
H10A0.50550.79860.11220.068*
H10B0.36070.84570.10190.068*
C110.5399 (6)0.8276 (3)0.1044 (5)0.0464 (13)
C120.5239 (6)0.8935 (3)0.1612 (5)0.0502 (14)
H120.44630.92540.10070.06*
C130.6219 (6)0.9127 (3)0.3069 (5)0.0490 (14)
C140.7395 (6)0.8654 (3)0.3968 (5)0.0498 (13)
C150.7552 (6)0.8002 (3)0.3398 (5)0.0611 (16)
H150.83340.76820.39930.073*
C160.6557 (6)0.7815 (3)0.1945 (6)0.0599 (15)
H160.66770.7370.15750.072*
O170.6123 (4)0.97621 (19)0.3725 (4)0.0741 (12)
C180.4880 (7)1.0251 (3)0.2884 (6)0.0797 (19)
H18A0.49461.06710.34740.12*
H18B0.38071.00390.26430.12*
H18C0.5051.03730.19680.12*
O190.8299 (4)0.88921 (18)0.5388 (4)0.0679 (11)
C200.9656 (6)0.8464 (3)0.6292 (5)0.0686 (17)
H20A1.01950.8690.72510.103*
H20B1.04310.84080.57860.103*
H20C0.92520.80080.64460.103*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.047 (3)0.043 (3)0.037 (3)0.001 (3)0.015 (2)0.006 (2)
C20.054 (3)0.045 (3)0.039 (3)0.000 (3)0.006 (3)0.006 (2)
C30.060 (4)0.062 (4)0.040 (3)0.001 (3)0.004 (3)0.013 (3)
C40.061 (4)0.053 (4)0.060 (4)0.007 (3)0.018 (3)0.010 (3)
C50.092 (5)0.043 (4)0.066 (4)0.010 (3)0.028 (4)0.001 (3)
C60.067 (4)0.047 (3)0.040 (3)0.002 (3)0.012 (3)0.006 (3)
F10.087 (3)0.103 (3)0.062 (2)0.025 (2)0.0110 (18)0.010 (2)
F20.093 (3)0.073 (2)0.103 (3)0.036 (2)0.028 (2)0.024 (2)
N70.047 (3)0.053 (3)0.030 (2)0.004 (2)0.010 (2)0.003 (2)
C80.041 (3)0.053 (3)0.029 (3)0.002 (3)0.010 (2)0.003 (3)
O90.078 (3)0.073 (3)0.0360 (19)0.027 (2)0.0258 (18)0.0142 (18)
C100.056 (3)0.066 (4)0.045 (3)0.009 (3)0.015 (3)0.003 (3)
C110.045 (3)0.051 (3)0.041 (3)0.004 (3)0.012 (2)0.003 (3)
C120.044 (3)0.056 (4)0.044 (3)0.001 (3)0.009 (3)0.004 (3)
C130.050 (3)0.049 (3)0.041 (3)0.000 (3)0.007 (3)0.011 (3)
C140.041 (3)0.058 (4)0.041 (3)0.001 (3)0.004 (2)0.006 (3)
C150.056 (3)0.057 (4)0.054 (3)0.011 (3)0.000 (3)0.014 (3)
C160.060 (4)0.059 (4)0.057 (3)0.000 (3)0.018 (3)0.009 (3)
O170.069 (3)0.062 (3)0.062 (2)0.020 (2)0.012 (2)0.008 (2)
C180.074 (4)0.059 (4)0.083 (4)0.016 (3)0.000 (3)0.006 (3)
O190.062 (2)0.070 (3)0.048 (2)0.019 (2)0.0085 (19)0.0103 (19)
C200.054 (3)0.078 (4)0.051 (3)0.010 (3)0.009 (3)0.000 (3)
Geometric parameters (Å, º) top
C1—C61.368 (6)C11—C161.369 (6)
C1—C21.392 (6)C11—C121.381 (6)
C1—N71.423 (6)C12—C131.386 (6)
C2—C31.362 (6)C12—H120.93
C2—H20.93C13—O171.367 (5)
C3—C41.356 (7)C13—C141.390 (6)
C3—F11.357 (5)C14—O191.368 (5)
C4—F21.359 (5)C14—C151.370 (6)
C4—C51.361 (6)C15—C161.383 (6)
C5—C61.380 (6)C15—H150.93
C5—H50.93C16—H160.93
C6—H60.93O17—C181.423 (5)
N7—C81.340 (5)C18—H18A0.96
N7—H70.89 (5)C18—H18B0.96
C8—O91.219 (5)C18—H18C0.96
C8—C101.515 (6)O19—C201.428 (5)
C10—C111.511 (6)C20—H20A0.96
C10—H10A0.97C20—H20B0.96
C10—H10B0.97C20—H20C0.96
C6—C1—C2120.0 (5)C16—C11—C10120.2 (5)
C6—C1—N7123.6 (4)C12—C11—C10121.0 (4)
C2—C1—N7116.4 (4)C11—C12—C13120.9 (5)
C3—C2—C1118.0 (5)C11—C12—H12119.6
C3—C2—H2121C13—C12—H12119.6
C1—C2—H2121O17—C13—C12124.6 (4)
C4—C3—F1119.2 (5)O17—C13—C14115.7 (4)
C4—C3—C2122.2 (5)C12—C13—C14119.7 (5)
F1—C3—C2118.5 (5)O19—C14—C15125.5 (4)
C3—C4—F2119.8 (5)O19—C14—C13115.3 (4)
C3—C4—C5119.9 (5)C15—C14—C13119.2 (4)
F2—C4—C5120.4 (5)C14—C15—C16120.5 (5)
C4—C5—C6119.5 (5)C14—C15—H15119.7
C4—C5—H5120.2C16—C15—H15119.7
C6—C5—H5120.2C11—C16—C15120.9 (5)
C1—C6—C5120.3 (5)C11—C16—H16119.5
C1—C6—H6119.9C15—C16—H16119.5
C5—C6—H6119.9C13—O17—C18118.1 (4)
C8—N7—C1125.9 (4)O17—C18—H18A109.5
C8—N7—H7118 (3)O17—C18—H18B109.5
C1—N7—H7116 (3)H18A—C18—H18B109.5
O9—C8—N7123.3 (5)O17—C18—H18C109.5
O9—C8—C10122.6 (4)H18A—C18—H18C109.5
N7—C8—C10114.1 (4)H18B—C18—H18C109.5
C11—C10—C8113.8 (4)C14—O19—C20117.5 (4)
C11—C10—H10A108.8O19—C20—H20A109.5
C8—C10—H10A108.8O19—C20—H20B109.5
C11—C10—H10B108.8H20A—C20—H20B109.5
C8—C10—H10B108.8O19—C20—H20C109.5
H10A—C10—H10B107.7H20A—C20—H20C109.5
C16—C11—C12118.8 (4)H20B—C20—H20C109.5
C6—C1—C2—C30.8 (7)C8—C10—C11—C1659.3 (6)
N7—C1—C2—C3178.9 (4)C8—C10—C11—C12121.7 (5)
C1—C2—C3—C40.6 (8)C16—C11—C12—C130.6 (7)
C1—C2—C3—F1178.5 (4)C10—C11—C12—C13179.5 (4)
F1—C3—C4—F20.8 (8)C11—C12—C13—O17178.9 (5)
C2—C3—C4—F2179.9 (5)C11—C12—C13—C140.8 (7)
F1—C3—C4—C5179.3 (5)O17—C13—C14—O190.2 (7)
C2—C3—C4—C50.2 (9)C12—C13—C14—O19180.0 (4)
C3—C4—C5—C60.8 (8)O17—C13—C14—C15179.1 (5)
F2—C4—C5—C6179.3 (5)C12—C13—C14—C150.6 (8)
C2—C1—C6—C50.2 (7)O19—C14—C15—C16179.4 (5)
N7—C1—C6—C5179.5 (5)C13—C14—C15—C160.2 (8)
C4—C5—C6—C10.6 (8)C12—C11—C16—C150.1 (8)
C6—C1—N7—C834.1 (7)C10—C11—C16—C15179.1 (5)
C2—C1—N7—C8145.6 (5)C14—C15—C16—C110.1 (8)
C1—N7—C8—O95.3 (8)C12—C13—O17—C183.0 (7)
C1—N7—C8—C10173.2 (4)C14—C13—O17—C18176.8 (5)
O9—C8—C10—C1120.3 (7)C15—C14—O19—C208.1 (8)
N7—C8—C10—C11161.2 (4)C13—C14—O19—C20172.6 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H7···O9i0.89 (5)1.98 (5)2.846 (5)163 (5)
Symmetry code: (i) x, y+3/2, z1/2.

Experimental details

Crystal data
Chemical formulaC16H15F2NO3
Mr307.29
Crystal system, space groupMonoclinic, P21/c
Temperature (K)295
a, b, c (Å)8.6440 (11), 18.867 (6), 9.4827 (13)
β (°) 111.019 (11)
V3)1443.6 (5)
Z4
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.26 × 0.26 × 0.23
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2855, 2689, 1089
Rint0.050
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.076, 0.161, 1.00
No. of reflections2689
No. of parameters203
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.19, 0.19

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H7···O9i0.89 (5)1.98 (5)2.846 (5)163 (5)
Symmetry code: (i) x, y+3/2, z1/2.
 

Acknowledgements

The X-ray data were collected at the Center for Research Facilities, Chungnam National University. This work was partially supported by the fund of New University for Regional Innovation (grant No. 05-Na-A-01) from the Ministry of Education and Human Resources Department, Republic of Korea.

References

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COMMUNICATIONS
ISSN: 2056-9890
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