3-Chloro-r-2,c-6-bis­(4-fluoro­phen­yl)-3-methyl­piperidin-4-one

Arulraj, R.; Sivakumar, S.; Thiruvalluvar, A.; Kaur, M.; Jasinski, J.P.

doi:10.1107/S2414314616015807

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 10| October 2016| x161580

https://doi.org/10.1107/S2414314616015807

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3-Chloro-r-2,c-6-bis(4-fluorophenyl)-3-methylpiperidin-4-one

R. Arulraj,^a S. Sivakumar,^b A. Thiruvalluvar,^c Manpreet Kaur ^d and Jerry P. Jasinski ^e ^*

^aResearch and Development Centre, Bharathiar University, Coimbatore 641 046, Tamilnadu, India, ^bDepartment of Chemistry, Thiruvalluvar Arts and Science College, Kurinjipadi 607 302, Tamilnadu, India, ^cPostgraduate Research Department of Physics, Rajah Serfoji Government College (Autonomous), Thanjavur 613 005, Tamilnadu, India, ^dDepartment of Chemistry, Keene State College, 229 Main Street, Keene NH 03435-2001, USA, and ^eDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA
^*Correspondence e-mail: jjasinski@keene.edu

Edited by R. J. Butcher, Howard University, USA (Received 18 September 2016; accepted 7 October 2016; online 11 October 2016)

The title compound, C₁₈H₁₆ClF₂NO, contains one independent molecule in the asymmetric unit, with the piperidin-4-one ring adopting a slightly distorted chair conformation and an equatorial orientation of all the substituents except chlorine. A single weak intermolecular C—H⋯O interaction influences the crystal packing, forming infinite one-dimensional zigzag chains along the a axis. The structure was refined as a two-component inversion twin.

Keywords: crystal structure; substituted piperidones; piperidin-4-one.

CCDC reference: 1508672

Structure description

Piperidones are an important group of heterocyclic compounds in the field of medicinal chemistry due to their biological activities, which include cytotoxic properties (Dimmock et al., 2001 ). They are also reported to possess analgesic, anti-inflammatory, central nervous system (CNS), local anaesthetic, anticancer, and antimicrobial activities (Perumal et al., 2001 ). The synthesis and stereodynamics of piperidin-4-ones and their derivatives have been reported (Ponnuswamy et al., 2002 ). The present investigation was undertaken to establish the molecular structure, the conformation of the heterocyclic ring and the orientation of the 4-fluorophenyl groups with respect to each other.

In the title compound, the piperidin-4-one ring is in a slightly distorted chair conformation [puckering parameters Q, θ, and φ = 0.548 (4) Å, 166.5 (4)°, and 182.7 (19)°, respectively] (Fig. 1), with an equatorial orientation of all the substituents except chlorine. The dihedral angle between the mean planes of the two fluoro-substituted benzene rings is 49.3 (3)°. Bond lengths are in normal ranges (Allen et al., 1987 ). No classical hydrogen bonds are observed and all intermolecular π–π interactions are greater than 4 Å. A single weak intermolecular C5—H5⋯O1ⁱ interaction influences the crystal packing, forming infinite one-dimensional zigzag chains along the a axis (Table 1 and Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1ⁱ	1.00	2.44	3.328 (5)	148
Symmetry code: (i) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z]$ .

Figure 1
The molecular structure, showing the atom-labeling scheme and 30% probability displacement ellipsoids.

Figure 2
The molecular packing, viewed along the c axis. Dashed lines indicate weak intermolecular C—H⋯O interactions. H atoms not involved in hydrogen bonding have been removed for clarity.

Synthesis and crystallization

A mixture of ammonium acetate (0.1 mol, 7.71 g), 4-fluorobenzaldehyde (0.2 mol, 21.0 ml), and 3-chlorobutan-2-one (0.1 mol, 10.1 ml) in distilled ethanol was heated first to boiling. After cooling, the viscous liquid obtained was dissolved in ether (200 ml) and shaken with concentrated hydrochloric acid (100 ml). The precipitated hydrochloride of 3-chloro-r-2,c-6-bis(4-fluorophenyl)-3-methylpiperidin-4-one was removed by filtration and washed first with a 40 ml mixture of ethanol and ether (1:1 v/v) and then with ether to remove most of the coloured impurities. The base was liberated from an ethanol solution by adding aqueous ammonia and then diluting with water. It was recrystallized from ethanol yielding colourless rod-like crystals (yield 3.5 g).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The structure was refined as a two-component inversion twin (TWIN Law = −1 0 0 0 1 0 0 0 −1; BASF = 0.37605).

Table 2
Experimental details

Crystal data
Chemical formula	C₁₈H₁₆ClF₂NO
M_r	335.77
Crystal system, space group	Orthorhombic, Pna2₁
Temperature (K)	173
a, b, c (Å)	6.2844 (2), 11.7141 (5), 21.6006 (10)
V (Å³)	1590.15 (11)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	2.35
Crystal size (mm)	0.48 × 0.15 × 0.14

Data collection
Diffractometer	Rigaku Oxford Diffraction
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2015 )
T_min, T_max	0.441, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	10608, 2341, 2207
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.614

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.122, 1.08
No. of reflections	2341
No. of parameters	210
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.56, −0.20
Absolute structure	Flack x determined using 650 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	0.02 (3)
Computer programs: CrysAlis PRO (Rigaku OD, 2015), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1508672

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314616015807/bv4004sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616015807/bv4004Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314616015807/bv4004Isup3.cml

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

3-Chloro-r-2,c-6-bis(4-fluorophenyl)-3-methylpiperidin-4-one top

Crystal data top

C₁₈H₁₆ClF₂NO	D_x = 1.403 Mg m⁻³
M_r = 335.77	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, Pna2₁	Cell parameters from 3685 reflections
a = 6.2844 (2) Å	θ = 3.8–71.6°
b = 11.7141 (5) Å	µ = 2.35 mm⁻¹
c = 21.6006 (10) Å	T = 173 K
V = 1590.15 (11) Å³	Needle, colourless
Z = 4	0.48 × 0.15 × 0.14 mm
F(000) = 696

Data collection top

Rigaku Oxford Diffraction diffractometer	2341 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source	2207 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.052
Detector resolution: 16.0416 pixels mm^-1	θ_max = 71.3°, θ_min = 3.8°
ω scans	h = −7→7
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015)	k = −14→14
T_min = 0.441, T_max = 1.000	l = −22→26
10608 measured reflections

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.049	w = 1/[σ²(F_o²) + (0.0862P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.122	(Δ/σ)_max < 0.001
S = 1.08	Δρ_max = 0.56 e Å⁻³
2341 reflections	Δρ_min = −0.20 e Å⁻³
210 parameters	Absolute structure: Flack x determined using 650 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
1 restraint	Absolute structure parameter: 0.02 (3)
Primary atom site location: structure-invariant direct methods

Special details top

Experimental. IR (KBr): 3325.34 (N-H), 3075.55, 3008.86 (υC-H), 1716.35 (υC=O), 1609.56, 1508.41 (υC=C), 767.12 (υC-Cl) cm^-1. ¹H NMR (500 MHz, CDCl₃): δ 7.54 - 7.03 (m, Aromatic protons), 4.06 - 4.03 (dd, H(6) proton), 3.94 (s, H(2) proton ), 3.45 - 3.40 (dd, H(5e) proton), 2.53-2.49 (dd, H(5a) proton), 2.07 (s, NH proton), 1.42 (s, CH₃ proton).

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a 2-component twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.08854 (13)	0.40538 (7)	0.52705 (7)	0.0446 (3)
F1	0.9527 (6)	0.3396 (4)	0.23545 (15)	0.0731 (10)
F2	0.6850 (5)	0.3219 (3)	0.76478 (13)	0.0620 (8)
O1	0.0162 (5)	0.6728 (2)	0.46516 (17)	0.0479 (8)
N1	0.5435 (5)	0.4835 (3)	0.49061 (14)	0.0317 (6)
H1	0.6721	0.4620	0.4976	0.038*
C1	0.4464 (5)	0.5400 (3)	0.54363 (19)	0.0321 (7)
H1A	0.5031	0.6197	0.5451	0.038*
C2	0.2029 (5)	0.5480 (3)	0.5335 (2)	0.0347 (8)
C3	0.1544 (6)	0.6011 (3)	0.4701 (2)	0.0353 (8)
C4	0.2845 (7)	0.5591 (4)	0.4168 (2)	0.0435 (9)
H4A	0.2677	0.6123	0.3815	0.052*
H4B	0.2310	0.4834	0.4037	0.052*
C5	0.5239 (6)	0.5493 (3)	0.43340 (19)	0.0357 (8)
H5	0.5827	0.6275	0.4404	0.043*
C6	0.6454 (6)	0.4932 (4)	0.38161 (19)	0.0377 (8)
C7	0.6428 (8)	0.3745 (4)	0.3746 (2)	0.0445 (9)
H7	0.5686	0.3288	0.4038	0.053*
C8	0.7467 (9)	0.3231 (4)	0.3258 (2)	0.0520 (10)
H8	0.7455	0.2424	0.3212	0.062*
C9	0.8523 (8)	0.3909 (5)	0.2838 (2)	0.0517 (11)
C10	0.8613 (8)	0.5067 (5)	0.2891 (2)	0.0541 (11)
H10	0.9369	0.5514	0.2597	0.065*
C11	0.7571 (8)	0.5577 (4)	0.3385 (2)	0.0462 (9)
H11	0.7623	0.6383	0.3430	0.055*
C12	0.5098 (6)	0.4818 (3)	0.60302 (18)	0.0324 (7)
C13	0.5488 (7)	0.5447 (4)	0.6568 (2)	0.0397 (9)
H13	0.5356	0.6254	0.6557	0.048*
C14	0.6059 (7)	0.4923 (4)	0.7111 (2)	0.0438 (9)
H14	0.6301	0.5357	0.7475	0.053*
C15	0.6271 (7)	0.3753 (4)	0.7115 (2)	0.0447 (9)
C16	0.5943 (6)	0.3102 (4)	0.6598 (2)	0.0405 (9)
H16	0.6126	0.2297	0.6612	0.049*
C17	0.5340 (6)	0.3637 (3)	0.60545 (19)	0.0359 (8)
H17	0.5088	0.3194	0.5694	0.043*
C18	0.0902 (7)	0.6093 (5)	0.5858 (2)	0.0495 (12)
H18A	−0.0600	0.6199	0.5750	0.074*
H18B	0.1569	0.6839	0.5925	0.074*
H18C	0.1007	0.5637	0.6237	0.074*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0329 (4)	0.0338 (4)	0.0673 (6)	−0.0052 (3)	−0.0073 (4)	0.0127 (4)
F1	0.071 (2)	0.104 (3)	0.0439 (15)	0.0193 (18)	0.0142 (14)	−0.0073 (16)
F2	0.0677 (18)	0.076 (2)	0.0426 (14)	0.0096 (14)	−0.0129 (13)	0.0101 (14)
O1	0.0387 (14)	0.0370 (14)	0.068 (2)	0.0091 (12)	−0.0078 (14)	0.0069 (14)
N1	0.0281 (14)	0.0305 (14)	0.0364 (17)	0.0024 (11)	−0.0015 (11)	−0.0010 (12)
C1	0.0264 (15)	0.0243 (14)	0.046 (2)	−0.0016 (11)	−0.0007 (14)	−0.0024 (14)
C2	0.0306 (16)	0.0272 (13)	0.046 (2)	0.0017 (11)	0.0021 (16)	0.0038 (15)
C3	0.0302 (18)	0.0279 (18)	0.048 (2)	−0.0026 (13)	−0.0069 (16)	0.0062 (15)
C4	0.043 (2)	0.043 (2)	0.044 (2)	0.0059 (17)	−0.0089 (17)	0.0057 (17)
C5	0.0354 (17)	0.0298 (17)	0.042 (2)	−0.0033 (14)	−0.0013 (16)	0.0013 (15)
C6	0.0366 (18)	0.0403 (19)	0.036 (2)	−0.0017 (16)	−0.0024 (15)	0.0034 (16)
C7	0.054 (2)	0.0347 (19)	0.045 (2)	−0.0015 (17)	0.0019 (19)	0.0008 (18)
C8	0.059 (3)	0.051 (2)	0.047 (2)	0.008 (2)	0.002 (2)	−0.002 (2)
C9	0.043 (2)	0.074 (3)	0.038 (2)	0.007 (2)	−0.0007 (19)	0.000 (2)
C10	0.049 (2)	0.074 (3)	0.040 (2)	0.000 (2)	0.0026 (18)	0.015 (2)
C11	0.046 (2)	0.046 (2)	0.047 (2)	−0.0040 (17)	−0.0002 (19)	0.0101 (18)
C12	0.0256 (15)	0.0325 (16)	0.0390 (18)	−0.0012 (13)	0.0022 (13)	−0.0025 (15)
C13	0.039 (2)	0.039 (2)	0.042 (2)	0.0005 (17)	0.0014 (16)	−0.0049 (18)
C14	0.039 (2)	0.055 (3)	0.037 (2)	−0.0006 (17)	−0.0026 (16)	−0.0086 (19)
C15	0.0363 (19)	0.057 (3)	0.041 (2)	0.0039 (18)	−0.0053 (17)	0.0046 (19)
C16	0.037 (2)	0.037 (2)	0.048 (2)	0.0057 (15)	−0.0024 (16)	0.0034 (18)
C17	0.0340 (17)	0.0339 (18)	0.0397 (19)	0.0027 (14)	0.0010 (15)	−0.0049 (15)
C18	0.041 (2)	0.057 (3)	0.051 (3)	0.0173 (18)	0.0040 (19)	−0.003 (2)

Geometric parameters (Å, º) top

Cl1—C2	1.824 (3)	C7—C8	1.379 (7)
F1—C9	1.360 (6)	C8—H8	0.9500
F2—C15	1.360 (5)	C8—C9	1.376 (7)
O1—C3	1.213 (5)	C9—C10	1.363 (8)
N1—H1	0.8599	C10—H10	0.9500
N1—C1	1.457 (5)	C10—C11	1.388 (7)
N1—C5	1.461 (5)	C11—H11	0.9500
C1—H1A	1.0000	C12—C13	1.397 (5)
C1—C2	1.548 (4)	C12—C17	1.392 (5)
C1—C12	1.507 (5)	C13—H13	0.9500
C2—C3	1.535 (6)	C13—C14	1.372 (7)
C2—C18	1.515 (6)	C14—H14	0.9500
C3—C4	1.495 (6)	C14—C15	1.376 (7)
C4—H4A	0.9900	C15—C16	1.368 (6)
C4—H4B	0.9900	C16—H16	0.9500
C4—C5	1.551 (5)	C16—C17	1.384 (6)
C5—H5	1.0000	C17—H17	0.9500
C5—C6	1.505 (6)	C18—H18A	0.9800
C6—C7	1.399 (6)	C18—H18B	0.9800
C6—C11	1.389 (6)	C18—H18C	0.9800
C7—H7	0.9500

C1—N1—H1	112.9	C7—C8—H8	120.6
C1—N1—C5	112.9 (3)	C9—C8—C7	118.7 (4)
C5—N1—H1	112.5	C9—C8—H8	120.6
N1—C1—H1A	107.5	F1—C9—C8	118.4 (5)
N1—C1—C2	109.3 (3)	F1—C9—C10	119.0 (5)
N1—C1—C12	110.7 (3)	C10—C9—C8	122.7 (4)
C2—C1—H1A	107.5	C9—C10—H10	120.9
C12—C1—H1A	107.5	C9—C10—C11	118.2 (4)
C12—C1—C2	114.1 (3)	C11—C10—H10	120.9
C1—C2—Cl1	110.2 (2)	C6—C11—C10	121.3 (4)
C3—C2—Cl1	103.0 (2)	C6—C11—H11	119.3
C3—C2—C1	110.3 (3)	C10—C11—H11	119.3
C18—C2—Cl1	107.9 (3)	C13—C12—C1	121.0 (3)
C18—C2—C1	112.7 (3)	C17—C12—C1	120.7 (3)
C18—C2—C3	112.4 (3)	C17—C12—C13	118.3 (4)
O1—C3—C2	120.1 (4)	C12—C13—H13	119.3
O1—C3—C4	123.4 (4)	C14—C13—C12	121.4 (4)
C4—C3—C2	116.5 (3)	C14—C13—H13	119.3
C3—C4—H4A	109.2	C13—C14—H14	120.8
C3—C4—H4B	109.2	C13—C14—C15	118.4 (4)
C3—C4—C5	112.1 (3)	C15—C14—H14	120.8
H4A—C4—H4B	107.9	F2—C15—C14	119.3 (4)
C5—C4—H4A	109.2	F2—C15—C16	118.3 (4)
C5—C4—H4B	109.2	C16—C15—C14	122.4 (4)
N1—C5—C4	108.5 (3)	C15—C16—H16	120.6
N1—C5—H5	108.9	C15—C16—C17	118.7 (4)
N1—C5—C6	110.8 (3)	C17—C16—H16	120.6
C4—C5—H5	108.9	C12—C17—H17	119.6
C6—C5—C4	110.7 (3)	C16—C17—C12	120.8 (4)
C6—C5—H5	108.9	C16—C17—H17	119.6
C7—C6—C5	120.5 (4)	C2—C18—H18A	109.5
C11—C6—C5	121.1 (4)	C2—C18—H18B	109.5
C11—C6—C7	118.3 (4)	C2—C18—H18C	109.5
C6—C7—H7	119.6	H18A—C18—H18B	109.5
C8—C7—C6	120.8 (4)	H18A—C18—H18C	109.5
C8—C7—H7	119.6	H18B—C18—H18C	109.5

Cl1—C2—C3—O1	106.0 (3)	C4—C5—C6—C11	98.1 (4)
Cl1—C2—C3—C4	−73.7 (4)	C5—N1—C1—C2	65.3 (3)
F1—C9—C10—C11	179.7 (4)	C5—N1—C1—C12	−168.2 (3)
F2—C15—C16—C17	179.6 (4)	C5—C6—C7—C8	177.4 (4)
O1—C3—C4—C5	136.3 (4)	C5—C6—C11—C10	−177.0 (4)
N1—C1—C2—Cl1	61.3 (3)	C6—C7—C8—C9	−0.3 (7)
N1—C1—C2—C3	−51.7 (3)	C7—C6—C11—C10	1.0 (7)
N1—C1—C2—C18	−178.1 (3)	C7—C8—C9—F1	−179.4 (4)
N1—C1—C12—C13	142.7 (3)	C7—C8—C9—C10	1.1 (8)
N1—C1—C12—C17	−36.4 (4)	C8—C9—C10—C11	−0.8 (7)
N1—C5—C6—C7	40.5 (5)	C9—C10—C11—C6	−0.3 (7)
N1—C5—C6—C11	−141.5 (4)	C11—C6—C7—C8	−0.7 (7)
C1—N1—C5—C4	−64.1 (4)	C12—C1—C2—Cl1	−63.2 (4)
C1—N1—C5—C6	174.3 (3)	C12—C1—C2—C3	−176.2 (3)
C1—C2—C3—O1	−136.4 (4)	C12—C1—C2—C18	57.4 (4)
C1—C2—C3—C4	43.9 (4)	C12—C13—C14—C15	0.9 (6)
C1—C12—C13—C14	179.8 (4)	C13—C12—C17—C16	0.3 (6)
C1—C12—C17—C16	179.3 (3)	C13—C14—C15—F2	179.5 (4)
C2—C1—C12—C13	−93.6 (4)	C13—C14—C15—C16	0.3 (7)
C2—C1—C12—C17	87.4 (4)	C14—C15—C16—C17	−1.1 (7)
C2—C3—C4—C5	−44.0 (4)	C15—C16—C17—C12	0.8 (6)
C3—C4—C5—N1	51.1 (4)	C17—C12—C13—C14	−1.2 (6)
C3—C4—C5—C6	172.9 (3)	C18—C2—C3—O1	−9.9 (5)
C4—C5—C6—C7	−79.9 (5)	C18—C2—C3—C4	170.4 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1ⁱ	1.00	2.44	3.328 (5)	148

Symmetry code: (i) x+1/2, −y+3/2, z.

Acknowledgements

The authors would like to acknowledge the Sophisticated Analytical Instrument Facility (SAIF), IITM, Chennai, for recording the NMR spectra. We extend our thanks to the Principal Dr N. Seraman, Chairman Mr R. Sattanathan and Treasurer Mr T. Ramalingam of Thiruvalluvar Arts and Science College for giving permission to carry out research work in the Chemistry Laboratory. JPJ acknowledges the NSF–MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.

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