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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 7| July 2008| Page o1355
doi:10.1107/S1600536808018795

4-Chloro-3-fluoro-2-methyl­aniline–pyrrolidine-2,5-dione (1/1)

Benjamin A. Mayes,a* Patrick McGarry,a Adel Moussaa and David J. Watkinb

aIdenix Pharmaceuticals, 60 Hampshire Street, Cambridge, MA 02139, USA, and bDepartment of Chemical Crystallography, Chemical Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, England
*Correspondence e-mail: mayes.ben@idenix.com

(Received 11 June 2008; accepted 20 June 2008; online 28 June 2008)

Chlorination of 3-fluoro-2-methyl­aniline with N-chloro­succinimide gave one major regioisomer whose structure was determined by X-ray crystallography. The product was found to have cocrystallized with succinimide, giving the title compound, C7H7ClFN·C4H5NO2. The crystal structure is stabilized by N—H⋯O hydrogen-bonding and π–π stacking inter­actions with a centroid–centroid distance of 3.4501 (8) Å.

Related literature

For related literature, see: Lazar et al. (2004[Lazar, C., Kluczyk, A., Kiyota, T. & Konishi, Y. (2004). J. Med. Chem. 47, 6973-6982.]); Marterer et al. (2003[Marterer, W., Prikoszovich, W., Wiss, J. & Prashad, M. (2003). Org. Process Res. Dev. 7, 318-323.]); Nickson & Roche-Dolson (1985[Nickson, T. E. & Roche-Dolson, C. A. (1985). Synthesis, 6, 669-670.]); Shapiro et al. (2006[Shapiro, R., Taylor, E. & Zimmerman, W. (2006). PCT Int. Appl. WO 2 006 062 978.]); Tukada & Mazaki (1997[Tukada, H. & Mazaki, Y. (1997). Chem. Lett., pp. 441-442.]); Zanka & Kubota (1999[Zanka, A. & Kubota, A. (1999). Synlett, 12, 1984-1986.]); Görbitz (1999[Görbitz, C. H. (1999). Acta Cryst. B55, 1090-1098.]).

[Scheme 1]

Experimental

Crystal data

  • C7H7ClFN·C4H5NO2

  • Mr = 258.68

  • Triclinic, [P \overline 1]

  • a = 7.3853 (2) Å

  • b = 7.4390 (2) Å

  • c = 11.5571 (4) Å

  • α = 73.1036 (13)°

  • β = 85.9336 (12)°

  • γ = 71.3703 (14)°

  • V = 575.53 (3) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.34 mm−1

  • T = 120 K

  • 0.75 × 0.44 × 0.41 mm
Data collection

  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) Tmin = 0.47, Tmax = 0.87

  • 16689 measured reflections

  • 2904 independent reflections

  • 2610 reflections with I > 2σ(I)

  • Rint = 0.033
Refinement

  • R[F2 > 2σ(F2)] = 0.032

  • wR(F2) = 0.087

  • S = 0.88

  • 2904 reflections

  • 154 parameters

  • H-atom parameters constrained

  • Δρmax = 0.38 e Å−3

  • Δρmin = −0.37 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
N12—H1⋯O16i 0.85 2.11 2.945 (2) 168
N8—H9⋯O16i 0.84 2.18 2.915 (2) 147
N8—H11⋯O17 0.88 2.17 3.030 (2) 166
Symmetry code: (i) -x+2, -y, -z+1.

Data collection: COLLECT (Nonius, 2001[Nonius (2001). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003[Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.]); molecular graphics: CAMERON (Watkin et al., 1996[Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, UK.]); software used to prepare material for publication: CRYSTALS.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808018795/lh2642sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808018795/lh2642Isup2.hkl

checkCIF report


Comment top

Chlorination of anilines with N-chlorosuccinimide (NCS) can provide access to poly-substituted aromatic compounds, useful as high-value synthetic intermediates (Lazar et al., 2004; Marterer et al., 2003; Nickson & Roche-Dolson, 1985; Shapiro et al., 2006; Zanka & Kubota, 1999). In the present example, treatment of 3-fluoro-2-methylaniline with NCS in polar solvents (e.g. N,N-dimethylformamide) resulted in chlorination para to the NH2 as the primary regioisomer in 10-fold excess relative to the undesired ortho isomer.

The sample was supplied in the form of large crystalline aggregates (4 mm across) coated with perfluoropolyether oil as a preservative. A large (0.8x0.8x0.4 mm) section was cut from the mass. The material did not have a strong cleavage - the crystals just fractured erratically. Because of the risk that further cutting might totally destroy the sample, an initial X-ray data set was measured from this large sample. The results confirmed the expected structure, but also showed a co-crystallized molecule of succinimide (Tukada & Mazaki, 1997).

At the end of the initial data collection, the sample was further subdivided into an irregular block approximately 0.41x0.44x0.75 mm. Prescans showed that the further cutting of the crystal had introduced fractures, but the sample was still amenable to analysis. Because of the degraded quality of the crystal, a data set with a target redundancy of 3 (as opposed to the usual 1) was collected. This highly redundant dataset would enable corrections to be made for the poor crystal quality.

Structure solution was slightly complicated because of the unexpected succinimide, but after that refinement and the location of all hydrogen atoms was normal. The two components are shown in Fig. 1. Fig. 2 shows the plane-to-plane alternate stacking of the components, with minimum inter-planar spacing of 3.37Å - presumable π - π stacking. The columns of molecules are interconnected by N-H···O hydrogen bonds which form discreet centrosymmetric 4-component clusters (Fig. 3).

Related literature top

For related literature, see: Lazar et al. (2004); Marterer et al. (2003); Nickson & Roche-Dolson (1985); Shapiro et al. (2006); Tukada & Mazaki (1997); Zanka & Kubota (1999); Görbitz (1999).

Experimental top

3-Fluoro-2-methylaniline (550 mg, 4.40 mmol) was dissolved in N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) or 1-methyl-2-pyrrolidinone (NMP) (5 ml) and cooled to 0–5°C under argon. N-Chlorosuccinimide (586 mg, 4.39 mmol) was added and the mixture was allowed to warm to room temperature over 15 h (Fig. 4). Dilution with ethyl acetate, washing with water, drying (sodium sulfate), filtration and evaporation of the solvents gave a crude oil.

Crystals were grown from isopropyl ether by seeding and storing at 4°C for two weeks. The solvent was decanted and the crystals coated with 2 drops of FOMBLIN perfluoropolyether oil.

Additional methods of characterization were recorded: m.p. 75.5–76.0°C; 1H (400 MHz, d3-MeCN): δ = 2.04 (3H, d, J 2.0 Hz, CH3), 2.62 (4H, s, CH2CH2), 4.32 (2H, br-s, NH2), 6.46 (1H, dd, J 8.6 Hz, J 0.8 Hz), 7.00 (1H, a-t, J 8.6 Hz), 8.83 (1H, br-s, NH). 13C (100 MHz, d3-MeCN): δ = 9.12, 9.18 (CH3), 30.26 (CH2CH2), 107.99, 108.19 (C-2), 111.16 (C-6), 111.34, 111.37 (C-4), 127.97, 127.98 (C-3), 147.76, 147.82 (C-5), 156.09, 158.47 (C-1), 179.33 (2 xC=O) (using crystallographic numbering).

Refinement top

The relatively large ratio of minimum to maximum corrections applied in the multiscan process (1:1.85) reflect the poor quality of the sample.

Difficulties in selecting an integration box suitable for all frames were taken into account (Görbitz, 1999) by the multi-scan inter-frame scaling (DENZO/SCALEPACK, Otwinowski & Minor, 1997).

The H atoms were all located in a difference map, but those attached to carbon atoms were repositioned geometrically. The H atoms were initially refined with soft restraints on the bond lengths and angles to regularize their geometry (C—H in the range 0.93–0.98, N—H in the range 0.86–0.89 N—H to 0.86 Å) and Uiso(H) (in the range 1.2–1.5 times Ueq of the parent atom), after which the positions were refined with riding constraints.

Computing details top

Data collection: COLLECT (Nonius, 2001); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS (Betteridge et al., 2003).

Figures top
[Figure 1] Fig. 1. The title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitary radius.
[Figure 2] Fig. 2. Plane-to-plane stacking of alternate molecules parallel to the a axis.
[Figure 3] Fig. 3. The hydrogen bonds (dotted lines) in the π -π stacks.
[Figure 4] Fig. 4. Synthetic scheme.
4-Chloro-3-fluoro-2-methylaniline–pyrrolidine-2,5-dione (1/1) top
Crystal data top
C7H7ClFN·C4H5NO2Z = 2
Mr = 258.68F(000) = 268
Triclinic, P1Dx = 1.493 Mg m−3
a = 7.3853 (2) ÅMo Kα radiation, λ = 0.71073 Å
b = 7.4390 (2) ÅCell parameters from 2870 reflections
c = 11.5571 (4) Åθ = 5–29°
α = 73.1036 (13)°µ = 0.34 mm−1
β = 85.9336 (12)°T = 120 K
γ = 71.3703 (14)°Plate, colourless
V = 575.53 (3) Å30.75 × 0.44 × 0.41 mm
Data collection top
Nonius KappaCCD
diffractometer		2610 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
ω scansθmax = 28.7°, θmin = 5.4°
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)		h = −9→9
Tmin = 0.47, Tmax = 0.87k = −10→9
16689 measured reflectionsl = −15→15
2904 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.087 Method = Modified Sheldrick w = 1/[σ2(F2) + (0.05P)2 + 0.35P],
where P = [max(Fo2,0) + 2Fc2]/3
S = 0.88(Δ/σ)max = 0.001
2904 reflectionsΔρmax = 0.38 e Å−3
154 parametersΔρmin = −0.37 e Å−3
0 restraints
Crystal data top
C7H7ClFN·C4H5NO2γ = 71.3703 (14)°
Mr = 258.68V = 575.53 (3) Å3
Triclinic, P1Z = 2
a = 7.3853 (2) ÅMo Kα radiation
b = 7.4390 (2) ŵ = 0.34 mm−1
c = 11.5571 (4) ÅT = 120 K
α = 73.1036 (13)°0.75 × 0.44 × 0.41 mm
β = 85.9336 (12)°
Data collection top
Nonius KappaCCD
diffractometer		2904 independent reflections
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)		2610 reflections with I > 2σ(I)
Tmin = 0.47, Tmax = 0.87Rint = 0.033
16689 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.087H-atom parameters constrained
S = 0.88Δρmax = 0.38 e Å−3
2904 reflectionsΔρmin = −0.37 e Å−3
154 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C110.94307 (16)0.30918 (17)0.66142 (11)0.0207
N120.99166 (15)0.16670 (15)0.59934 (9)0.0223
C131.10284 (16)−0.01507 (17)0.66627 (11)0.0205
C141.14595 (16)−0.00013 (17)0.78815 (10)0.0204
C151.04097 (16)0.21516 (17)0.78494 (11)0.0211
O161.15499 (13)−0.16202 (13)0.62979 (8)0.0275
O170.83954 (13)0.47656 (13)0.62086 (8)0.0280
H1411.2797−0.03250.79870.0245*
H1421.0987−0.09160.85110.0240*
H1511.12210.28590.79390.0258*
H1520.94710.22710.84740.0263*
H10.95100.18240.52870.0265*
C10.34402 (16)0.96277 (18)0.14329 (10)0.0201
C20.28607 (16)1.11710 (17)0.19551 (11)0.0207
C30.34232 (16)1.08204 (17)0.31427 (11)0.0217
C40.45586 (16)0.89539 (17)0.37673 (10)0.0210
C50.51642 (16)0.74038 (17)0.32214 (10)0.0188
C60.45694 (16)0.77380 (17)0.20237 (10)0.0194
C70.51289 (19)0.60873 (19)0.14308 (12)0.0269
N80.63360 (16)0.55949 (16)0.38422 (10)0.0277
Cl90.14163 (4)1.34735 (4)0.11329 (3)0.0293
F100.28435 (11)0.99849 (12)0.02806 (6)0.0291
H310.30121.18510.34750.0277*
H410.49530.87050.45810.0257*
H710.65030.55180.14140.0420*
H720.46410.50270.18630.0416*
H730.46390.65360.06180.0429*
H90.66980.46640.35190.0324*
H110.67360.53920.45850.0317*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C110.0199 (5)0.0202 (5)0.0235 (6)−0.0059 (4)0.0007 (4)−0.0088 (4)
N120.0264 (5)0.0201 (5)0.0187 (5)−0.0024 (4)−0.0048 (4)−0.0072 (4)
C130.0196 (5)0.0201 (5)0.0209 (5)−0.0039 (4)−0.0013 (4)−0.0064 (4)
C140.0196 (5)0.0216 (5)0.0195 (5)−0.0049 (4)−0.0029 (4)−0.0061 (4)
C150.0198 (5)0.0232 (5)0.0221 (6)−0.0066 (4)−0.0014 (4)−0.0090 (4)
O160.0325 (5)0.0212 (4)0.0259 (5)0.0005 (4)−0.0056 (4)−0.0108 (4)
O170.0302 (5)0.0206 (4)0.0305 (5)−0.0012 (3)−0.0058 (4)−0.0090 (4)
C10.0196 (5)0.0262 (6)0.0156 (5)−0.0089 (4)−0.0015 (4)−0.0051 (4)
C20.0180 (5)0.0187 (5)0.0228 (6)−0.0049 (4)−0.0023 (4)−0.0023 (4)
C30.0217 (5)0.0206 (5)0.0237 (6)−0.0051 (4)0.0005 (4)−0.0094 (4)
C40.0213 (5)0.0228 (5)0.0184 (5)−0.0043 (4)−0.0026 (4)−0.0074 (4)
C50.0165 (5)0.0190 (5)0.0196 (5)−0.0041 (4)0.0003 (4)−0.0050 (4)
C60.0181 (5)0.0218 (5)0.0205 (5)−0.0081 (4)0.0020 (4)−0.0077 (4)
C70.0290 (6)0.0277 (6)0.0276 (6)−0.0077 (5)0.0010 (5)−0.0144 (5)
N80.0317 (6)0.0207 (5)0.0241 (5)0.0027 (4)−0.0051 (4)−0.0071 (4)
Cl90.02920 (17)0.02088 (16)0.03136 (17)−0.00375 (11)−0.00674 (12)−0.00040 (11)
F100.0341 (4)0.0346 (4)0.0175 (3)−0.0092 (3)−0.0072 (3)−0.0055 (3)
Geometric parameters (Å, º) top
C11—N121.3890 (14)C2—C31.3885 (17)
C11—C151.5141 (16)C2—Cl91.7335 (12)
C11—O171.2075 (14)C3—C41.3826 (16)
N12—C131.3689 (15)C3—H310.913
N12—H10.852C4—C51.4075 (16)
C13—C141.5082 (16)C4—H410.952
C13—O161.2235 (14)C5—C61.4096 (16)
C14—C151.5309 (16)C5—N81.3629 (14)
C14—H1410.947C6—C71.5076 (16)
C14—H1420.970C7—H710.968
C15—H1510.943C7—H720.963
C15—H1520.968C7—H730.955
C1—C21.3848 (17)N8—H90.842
C1—C61.3826 (16)N8—H110.882
C1—F101.3569 (13)
N12—C11—C15107.80 (9)C1—C2—C3118.84 (11)
N12—C11—O17124.27 (11)C1—C2—Cl9119.74 (9)
C15—C11—O17127.93 (11)C3—C2—Cl9121.41 (9)
C11—N12—C13113.60 (10)C2—C3—C4119.37 (11)
C11—N12—H1125.7C2—C3—H31117.6
C13—N12—H1120.5C4—C3—H31123.1
N12—C13—C14108.74 (9)C3—C4—C5121.32 (11)
N12—C13—O16123.80 (11)C3—C4—H41119.8
C14—C13—O16127.46 (11)C5—C4—H41118.9
C13—C14—C15104.82 (9)C4—C5—C6119.65 (11)
C13—C14—H141109.5C4—C5—N8120.21 (11)
C15—C14—H141111.9C6—C5—N8120.13 (10)
C13—C14—H142109.2C5—C6—C1117.02 (10)
C15—C14—H142111.7C5—C6—C7120.92 (11)
H141—C14—H142109.5C1—C6—C7122.05 (11)
C14—C15—C11104.97 (9)C6—C7—H71111.7
C14—C15—H151114.0C6—C7—H72111.2
C11—C15—H151109.0H71—C7—H72106.7
C14—C15—H152112.8C6—C7—H73111.5
C11—C15—H152109.9H71—C7—H73108.1
H151—C15—H152106.2H72—C7—H73107.4
C2—C1—C6123.78 (11)C5—N8—H9120.4
C2—C1—F10118.07 (10)C5—N8—H11120.3
C6—C1—F10118.14 (10)H9—N8—H11119.3
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N12—H1···O16i0.852.112.945 (2)168
N8—H9···O16i0.842.182.915 (2)147
N8—H11···O170.882.173.030 (2)166
Symmetry code: (i) −x+2, −y, −z+1.

Experimental details

Crystal data
Chemical formulaC7H7ClFN·C4H5NO2
Mr258.68
Crystal system, space groupTriclinic, P1
Temperature (K)120
a, b, c (Å)7.3853 (2), 7.4390 (2), 11.5571 (4)
α, β, γ (°)73.1036 (13), 85.9336 (12), 71.3703 (14)
V (Å3)575.53 (3)
Z2
Radiation typeMo Kα
µ (mm−1)0.34
Crystal size (mm)0.75 × 0.44 × 0.41
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
Tmin, Tmax0.47, 0.87
No. of measured, independent and
observed [I > 2σ(I)] reflections		16689, 2904, 2610
Rint0.033
(sin θ/λ)max (Å−1)0.675
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.087, 0.88
No. of reflections2904
No. of parameters154
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.38, −0.37

Computer programs: COLLECT (Nonius, 2001), DENZO/SCALEPACK (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), CRYSTALS (Betteridge et al., 2003), CAMERON (Watkin et al., 1996).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N12—H1···O16i0.852.112.945 (2)168
N8—H9···O16i0.842.182.915 (2)147
N8—H11···O170.882.173.030 (2)166
Symmetry code: (i) −x+2, −y, −z+1.
 

Acknowledgements

We thank Dr Sarah F. Jenkinson, University of Oxford, for her assistance in the preparation of the manuscript.

References

First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
 First citationBetteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.  Web of Science CrossRef IUCr Journals Google Scholar
 First citationGörbitz, C. H. (1999). Acta Cryst. B55, 1090–1098.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationLazar, C., Kluczyk, A., Kiyota, T. & Konishi, Y. (2004). J. Med. Chem. 47, 6973–6982.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationMarterer, W., Prikoszovich, W., Wiss, J. & Prashad, M. (2003). Org. Process Res. Dev. 7, 318–323.  Web of Science CrossRef CAS Google Scholar
 First citationNickson, T. E. & Roche-Dolson, C. A. (1985). Synthesis, 6, 669–670.  CrossRef Google Scholar
 First citationNonius (2001). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
 First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
 First citationShapiro, R., Taylor, E. & Zimmerman, W. (2006). PCT Int. Appl. WO 2 006 062 978.  Google Scholar
 First citationTukada, H. & Mazaki, Y. (1997). Chem. Lett., pp. 441–442.  Google Scholar
 First citationWatkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, UK.  Google Scholar
 First citationZanka, A. & Kubota, A. (1999). Synlett, 12, 1984–1986.  CrossRef Google Scholar

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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 7| July 2008| Page o1355
doi:10.1107/S1600536808018795
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