6-Fluoro-4-methyl-2-(3-pyrid­yl)-1,2,3,4-tetra­hydro­quinoline

In the title compound, C₁₅H₁₅FN₂, the tetrahydropyridine ring adopts a half-chair conformation. Hydrogen bonds of the type N—H...N form extended zigzag chains related by 2₁ screw axes running along [010]. Additionally, C—H...π hydrogen bonds contribute to the stabilization of the crystal structure, which packs with an efficiency of 68.2%.

Key indicators

• Single-crystal synchrotron study
• T = 120 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.063
• wR factor = 0.178
• Data-to-parameter ratio = 24.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97

Alert level G
  ABSMU_01  Radiation type not identified. Calculation of
            _exptl_absorpt_correction_mu not performed.
PLAT793_ALERT_1_G Check the Absolute Configuration of C2     = ...          S
PLAT793_ALERT_1_G Check the Absolute Configuration of C4     = ...          S

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 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

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S1. Comment

In this work, the structure of the compound 6-fluoro-4-methyl-2-(3'-pyridil)-1,2,3,4-tetrahydroquinoline (I) is presented, which was prepared from the related homoallylamine derivative by mixing with H₂SO₄ (85%),CHCl₃ at 363 K for 10–12 hrs (Vargas et al., 2003). There is a binary axis bisecting the C2—C3 and C6—C17 bonds (Cs = +8.2 (2)°) (Cremer & Pople,1975) in the pyridine ring; therefore, this ring adopts the half-chair conformation (Fig. 1), as seen in the related structures DISHIW (Obodovskaya etal., 1985) and IXAHOE (Rybakov et al., 2004) (Cambridge Structural Database, 2006). C2 and C3 are out of the pyridine ring mean plane by 0.302 (1)Å and -0.314 (1) Å, respectively. The methyl group in position 4 and the pyridyl group in position 2 are bisectorial and equatorial to the pyridine ring, respectively. The N1—C17 distance is shorter than the N1—C2 distance by 0.0604 (2)Å (Table 1). The asymmetry in the N—C distances have also been observed in three 1,2,3,4-tetrahydroquinoline compounds substituted in positions 2,4,6 reported in the CSD [DISHIW, IXAHOE, MHXHQV] (Obodovskaya et al., 1985; Rybakov et al., 2004; Zavalishin et al., 1977), and have been attributed to resonance effects between the benzene ring and the electron pair of N1, awarding a pseudo double character to the N1—C17 bond.

The crystal structure is essentially lamellar, with layers of molecules bonded by hydrogen bonds packing in a sinusoidal way along the [001] direction (Fig.2 & Table 2). This interaction by hydrogen bond forms extended zigzag chains along [010]. In the chain depicted in Fig. 2, pairs of molecules are related by 2₁ screw axis. Non-conventional C—H···aromatic hydrogen bonds between benzene rings (C5—C8/C16—C17) and hydrogen atoms of neighboring layers link every two layer. Between these hydrogen-bonded double-layers there are intercalated H···H hydrophophic interactions; all these attractive and disruptive interactions contribute to the stabilization of the crystal structure, which packs with an efficiency of 68.2% of filled space.

Related literature

For related literature, see: Allen (2002); Cremer & Pople (1975); Obodovskaya et al. (1985); Rybakov et al. (2004); Vargas-Méndez et al. (2003); Zavalishin et al. (1977).

S2. Experimental

The synthesis of the fluoro tetrahydroquinoline derivative is explained elsewhere (Vargas et al., 2003). Single crystals were obtained from the slow evaporation of 50 mg of C₁₅H₁₅FN₂ from chloroform.

S3. Refinement

The H atom of N1 refined freely. The other H atoms were positioned geometrically and refined using a riding model, with C—H = 0.95 Å for aromatic H atoms and C—H = 0.99 Å for methylene H atoms, both with U_iso(H) = 1.2U_eq(C), and C—H = 0.98 Å and U_iso(H) = 1.5U_eq(C) for methyl H atoms.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: PLATON (Spek, 2003) and publCIF (Westrip, 2007).

Figures

	Fig. 1. Asymmetric unit and labeling of atoms in (I), showing thermal ellipsoids with 50% probability.
	Fig. 2. Layer packing of (I) seen down b. [Symmetry codes: (i) -x + 3/2, y + 1/2, z; (ii) -x + 1, y - 1/2, -z + 1/2.]

6-Fluoro-4-methyl-2-(3-pyridyl)-1,2,3,4-tetrahydroquinoline

Crystal data

C15H15FN2	Dx = 1.282 Mg m^−3
Mr = 242.29	Melting point = 387–388 K
Orthorhombic, Pbca	Synchrotron radiation, λ = 0.50915 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 3048 reflections
a = 16.2219 (7) Å	θ = 9.1–42.7°
b = 8.5208 (2) Å	µ = 0.04 mm^−1
c = 18.1612 (7) Å	T = 120 K
V = 2510.31 (16) Å^3	Needle, colourless
Z = 8	0.20 × 0.05 × 0.05 mm
F(000) = 1024

Data collection

Bruker SMART CCD area-detector diffractometer	3706 reflections with I > 2σ(I)
Radiation source: Beam line ID-11 ESRF	Rint = 0.033
Double crystal Si monochromator	θmax = 22.1°, θmin = 1.6°
Detector resolution: 8.0 pixels mm^-1	h = −22→23
oscillation scans	k = −12→12
23667 measured reflections	l = −26→26
4099 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.178	H atoms treated by a mixture of independent and constrained refinement
S = 1.13	w = 1/[σ^2(Fo^2) + (0.0761P)^2 + 1.7041P] where P = (Fo^2 + 2Fc^2)/3
4099 reflections	(Δ/σ)max < 0.001
167 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.39 e Å^−3

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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
F1	0.25209 (6)	0.89015 (15)	0.22468 (6)	0.0409 (3)
N1	0.56467 (7)	0.87020 (14)	0.10281 (7)	0.0219 (3)
N2	0.84577 (8)	0.68002 (16)	0.08529 (8)	0.0274 (3)
C2	0.62185 (8)	0.75116 (16)	0.13001 (7)	0.0205 (3)
C3	0.57922 (9)	0.59195 (16)	0.12436 (8)	0.0239 (3)
C4	0.50292 (9)	0.58544 (17)	0.17442 (8)	0.0246 (3)
C5	0.37335 (8)	0.74564 (19)	0.19852 (8)	0.0259 (4)
C6	0.32926 (8)	0.8843 (2)	0.19385 (8)	0.0272 (4)
C7	0.35906 (8)	1.01602 (18)	0.15868 (8)	0.0253 (4)
C8	0.43766 (8)	1.00741 (17)	0.12804 (8)	0.0225 (3)
C9	0.70204 (8)	0.75541 (16)	0.08748 (7)	0.0203 (3)
C10	0.77139 (8)	0.68369 (18)	0.11756 (8)	0.0239 (3)
C11	0.85312 (9)	0.75054 (19)	0.01961 (9)	0.0278 (4)
C12	0.78812 (10)	0.8257 (2)	−0.01530 (8)	0.0301 (4)
C13	0.71109 (9)	0.82767 (19)	0.01895 (8)	0.0265 (4)
C14	0.45329 (11)	0.4364 (2)	0.15721 (13)	0.0403 (5)
C16	0.45266 (8)	0.73577 (16)	0.16809 (7)	0.0202 (3)
C17	0.48560 (7)	0.87039 (15)	0.13369 (7)	0.0186 (3)
H1	0.5849 (12)	0.968 (3)	0.1038 (11)	0.025 (5)*
H2	0.63390	0.77310	0.18300	0.0250*
H3A	0.61830	0.50820	0.13880	0.0290*
H3B	0.56240	0.57300	0.07270	0.0290*
H4	0.52270	0.57720	0.22640	0.0290*
H5	0.34990	0.65700	0.22240	0.0310*
H7	0.32710	1.10930	0.15550	0.0300*
H8	0.45930	1.09590	0.10280	0.0270*
H10	0.76570	0.63400	0.16410	0.0290*
H11	0.90530	0.74890	−0.00410	0.0330*
H12	0.79590	0.87500	−0.06170	0.0360*
H13	0.66550	0.87750	−0.00400	0.0320*
H14A	0.48900	0.34430	0.16230	0.0480*
H14B	0.43230	0.44200	0.10670	0.0480*
H14C	0.40700	0.42800	0.19160	0.0480*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
F1	0.0180 (4)	0.0536 (7)	0.0512 (6)	0.0078 (4)	0.0113 (4)	0.0115 (5)
N1	0.0157 (5)	0.0172 (5)	0.0327 (6)	0.0014 (4)	0.0026 (4)	0.0051 (4)
N2	0.0198 (5)	0.0270 (6)	0.0353 (6)	0.0051 (4)	0.0010 (4)	0.0001 (5)
C2	0.0170 (5)	0.0225 (6)	0.0221 (5)	0.0032 (4)	−0.0001 (4)	0.0019 (4)
C3	0.0226 (6)	0.0186 (6)	0.0306 (6)	0.0024 (5)	0.0001 (5)	0.0034 (5)
C4	0.0212 (6)	0.0218 (6)	0.0307 (6)	0.0010 (5)	−0.0004 (5)	0.0085 (5)
C5	0.0192 (6)	0.0302 (7)	0.0284 (6)	−0.0006 (5)	0.0014 (5)	0.0072 (5)
C6	0.0141 (5)	0.0384 (8)	0.0290 (6)	0.0030 (5)	0.0021 (5)	0.0033 (6)
C7	0.0181 (6)	0.0277 (7)	0.0300 (6)	0.0055 (5)	−0.0024 (5)	0.0009 (5)
C8	0.0186 (5)	0.0208 (6)	0.0280 (6)	0.0019 (4)	−0.0016 (4)	0.0019 (5)
C9	0.0176 (5)	0.0213 (6)	0.0221 (5)	0.0028 (4)	0.0009 (4)	0.0003 (4)
C10	0.0199 (6)	0.0255 (6)	0.0264 (6)	0.0047 (5)	0.0000 (4)	0.0023 (5)
C11	0.0210 (6)	0.0293 (7)	0.0330 (7)	0.0025 (5)	0.0061 (5)	−0.0047 (6)
C12	0.0269 (7)	0.0384 (8)	0.0250 (6)	0.0036 (6)	0.0060 (5)	0.0028 (6)
C13	0.0227 (6)	0.0330 (7)	0.0238 (6)	0.0054 (5)	0.0013 (5)	0.0044 (5)
C14	0.0312 (8)	0.0226 (7)	0.0671 (12)	−0.0030 (6)	0.0017 (8)	0.0094 (7)
C16	0.0172 (5)	0.0219 (6)	0.0216 (5)	0.0004 (4)	−0.0019 (4)	0.0041 (4)
C17	0.0149 (5)	0.0191 (6)	0.0218 (5)	0.0001 (4)	−0.0016 (4)	0.0013 (4)

Geometric parameters (Å, º)

F1—C6	1.3723 (17)	C11—C12	1.387 (2)
N1—C2	1.4606 (18)	C12—C13	1.396 (2)
N1—C17	1.3999 (16)	C16—C17	1.4112 (18)
N2—C10	1.3418 (19)	C2—H2	1.0000
N2—C11	1.341 (2)	C3—H3A	0.9900
N1—H1	0.90 (2)	C3—H3B	0.9900
C2—C9	1.5133 (18)	C4—H4	1.0000
C2—C3	1.5261 (19)	C5—H5	0.9500
C3—C4	1.537 (2)	C7—H7	0.9500
C4—C14	1.536 (2)	C8—H8	0.9500
C4—C16	1.523 (2)	C10—H10	0.9500
C5—C16	1.4028 (19)	C11—H11	0.9500
C5—C6	1.384 (2)	C12—H12	0.9500
C6—C7	1.379 (2)	C13—H13	0.9500
C7—C8	1.3931 (19)	C14—H14A	0.9800
C8—C17	1.4066 (19)	C14—H14B	0.9800
C9—C10	1.3919 (19)	C14—H14C	0.9800
C9—C13	1.396 (2)
F1···H2^i	2.7400	H2···C16	2.9700
F1···H5^ii	2.8100	H2···H4	2.5800
F1···H14C^ii	2.6700	H2···H10	2.4700
N1···N2^iii	3.0300 (18)	H2···F1^x	2.7400
N2···C13^iv	3.364 (2)	H3A···C10	2.9200
N2···N1^iv	3.0300 (18)	H3A···H14A	2.5600
N1···H13	2.5400	H3B···C17	3.0300
N2···H1^iv	2.15 (2)	H3B···H14B	2.4700
C10···C13^iv	3.534 (2)	H4···H2	2.5800
C13···C10^iii	3.534 (2)	H4···C7^xi	2.8800
C13···N2^iii	3.364 (2)	H4···C8^xi	2.7800
C5···H14C	2.7600	H4···C17^xi	3.1000
C5···H12^v	2.9700	H5···C14	2.7800
C7···H13^vi	2.9800	H5···H14C	2.2300
C7···H4^vii	2.8800	H5···H10^i	2.4800
C8···H14A^viii	3.0500	H5···F1^xii	2.8100
C8···H13^vi	2.9700	H8···C14^viii	3.0700
C8···H4^vii	2.7800	H8···H1	2.3100
C10···H3A	2.9200	H8···H14A^viii	2.4200
C10···H1^iv	2.98 (2)	H10···H2	2.4700
C11···H1^iv	3.02 (2)	H10···H5^x	2.4800
C13···H1	2.83 (2)	H11···C16^xiii	3.0800
C14···H5	2.7800	H11···C17^xiii	2.8800
C14···H8^ix	3.0700	H12···C5^xiii	2.9700
C16···H2	2.9700	H13···N1	2.5400
C16···H11^v	3.0800	H13···H1	2.4800
C17···H3B	3.0300	H13···C7^vi	2.9800
C17···H11^v	2.8800	H13···C8^vi	2.9700
C17···H4^vii	3.1000	H14A···C8^ix	3.0500
H1···C13	2.83 (2)	H14A···H3A	2.5600
H1···H8	2.3100	H14A···H8^ix	2.4200
H1···H13	2.4800	H14B···H3B	2.4700
H1···N2^iii	2.15 (2)	H14C···C5	2.7600
H1···C10^iii	2.98 (2)	H14C···H5	2.2300
H1···C11^iii	3.02 (2)	H14C···F1^xii	2.6700
C2—N1—C17	116.56 (11)	C3—C2—H2	109.00
C10—N2—C11	117.26 (13)	C9—C2—H2	109.00
C2—N1—H1	114.0 (13)	C2—C3—H3A	109.00
C17—N1—H1	109.1 (13)	C2—C3—H3B	109.00
N1—C2—C3	107.87 (11)	C4—C3—H3A	109.00
N1—C2—C9	110.90 (11)	C4—C3—H3B	109.00
C3—C2—C9	112.12 (11)	H3A—C3—H3B	108.00
C2—C3—C4	110.93 (11)	C3—C4—H4	108.00
C14—C4—C16	113.55 (12)	C14—C4—H4	108.00
C3—C4—C14	109.37 (13)	C16—C4—H4	108.00
C3—C4—C16	110.87 (11)	C6—C5—H5	120.00
C6—C5—C16	120.07 (14)	C16—C5—H5	120.00
C5—C6—C7	122.83 (13)	C6—C7—H7	121.00
F1—C6—C5	118.53 (14)	C8—C7—H7	121.00
F1—C6—C7	118.64 (14)	C7—C8—H8	119.00
C6—C7—C8	117.58 (13)	C17—C8—H8	119.00
C7—C8—C17	121.37 (13)	N2—C10—H10	118.00
C2—C9—C13	123.77 (12)	C9—C10—H10	118.00
C10—C9—C13	117.29 (12)	N2—C11—H11	118.00
C2—C9—C10	118.94 (12)	C12—C11—H11	118.00
N2—C10—C9	124.44 (14)	C11—C12—H12	121.00
N2—C11—C12	123.09 (14)	C13—C12—H12	121.00
C11—C12—C13	118.84 (14)	C9—C13—H13	120.00
C9—C13—C12	119.08 (13)	C12—C13—H13	120.00
C4—C16—C17	120.96 (11)	C4—C14—H14A	109.00
C5—C16—C17	118.23 (12)	C4—C14—H14B	109.00
C4—C16—C5	120.78 (12)	C4—C14—H14C	109.00
C8—C17—C16	119.84 (11)	H14A—C14—H14B	109.00
N1—C17—C8	118.58 (12)	H14A—C14—H14C	110.00
N1—C17—C16	121.56 (11)	H14B—C14—H14C	110.00
N1—C2—H2	109.00
C17—N1—C2—C3	51.97 (15)	C16—C5—C6—C7	1.4 (2)
C17—N1—C2—C9	175.10 (11)	C6—C5—C16—C4	178.44 (13)
C2—N1—C17—C8	160.05 (12)	C6—C5—C16—C17	0.5 (2)
C2—N1—C17—C16	−21.78 (18)	F1—C6—C7—C8	179.78 (13)
C11—N2—C10—C9	0.0 (2)	C5—C6—C7—C8	−1.2 (2)
C10—N2—C11—C12	0.1 (2)	C6—C7—C8—C17	−1.0 (2)
N1—C2—C3—C4	−63.55 (14)	C7—C8—C17—N1	−178.91 (13)
C9—C2—C3—C4	174.07 (11)	C7—C8—C17—C16	2.9 (2)
N1—C2—C9—C10	162.18 (12)	C2—C9—C10—N2	−179.82 (14)
N1—C2—C9—C13	−17.85 (18)	C13—C9—C10—N2	0.2 (2)
C3—C2—C9—C10	−77.19 (16)	C2—C9—C13—C12	179.53 (14)
C3—C2—C9—C13	102.79 (16)	C10—C9—C13—C12	−0.5 (2)
C2—C3—C4—C14	170.01 (13)	N2—C11—C12—C13	−0.4 (2)
C2—C3—C4—C16	44.05 (15)	C11—C12—C13—C9	0.6 (2)
C3—C4—C16—C5	168.74 (12)	C4—C16—C17—N1	1.35 (19)
C3—C4—C16—C17	−13.41 (18)	C4—C16—C17—C8	179.50 (12)
C14—C4—C16—C5	45.14 (19)	C5—C16—C17—N1	179.26 (12)
C14—C4—C16—C17	−137.01 (15)	C5—C16—C17—C8	−2.59 (19)
C16—C5—C6—F1	−179.54 (13)

Symmetry codes: (i) x−1/2, y, −z+1/2; (ii) −x+1/2, y+1/2, z; (iii) −x+3/2, y+1/2, z; (iv) −x+3/2, y−1/2, z; (v) x−1/2, −y+3/2, −z; (vi) −x+1, −y+2, −z; (vii) −x+1, y+1/2, −z+1/2; (viii) x, y+1, z; (ix) x, y−1, z; (x) x+1/2, y, −z+1/2; (xi) −x+1, y−1/2, −z+1/2; (xii) −x+1/2, y−1/2, z; (xiii) x+1/2, −y+3/2, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N2^iii	0.90 (2)	2.15 (2)	3.0300 (18)	165.5 (18)
C4—H4···Cg^xi	1.00	2.87	3.7421 (16)	146

Symmetry codes: (iii) −x+3/2, y+1/2, z; (xi) −x+1, y−1/2, −z+1/2.