2-Chloro-12-phenyl-6,7,8,9,10,11-hexa­hydro­cyclo­octa­[b]quinoline

Bazgir, A.; Astaraki, A.M.

doi:10.1107/S1600536808009239

organic compounds

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ISSN: 2056-9890

Volume 64| Part 5| May 2008| Page o831

doi:10.1107/S1600536808009239

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2-Chloro-12-phenyl-6,7,8,9,10,11-hexahydrocycloocta[b]quinoline

Ayoob Bazgir ^a ^* and Ali Mohammad Astaraki ^a

^aDepartment of Chemistry, Islamic Azad University, Dorood Branch, Dorood 688173551, Iran
^*Correspondence e-mail: a_bazgir@yahoo.com

(Received 4 April 2008; accepted 5 April 2008; online 10 April 2008)

In the molecule of the title compound, C₂₁H₂₀ClN, the quinoline group is nearly planar and is oriented at a dihedral angle of 77.21 (3)° with respect to the phenyl ring. The conformation of the cyclooctane ring is twist-boat. In the crystal structure, there are some weak π–π interactions [centroid-to-centroid distances of 3.7414 (11) and 3.8633 (12) Å] between the rings of the quinoline groups.

Related literature

For general background, see: Kalluraya & Sreenivasa (1998 ); Doube et al. (1998 ); Maguire et al. (1994 ). For bond-length data, see: Allen et al. (1987 ).

Experimental

Crystal data

C₂₁H₂₀ClN
M_r = 321.83
Triclinic, $[P \overline 1]$
a = 9.837 (2) Å
b = 9.980 (2) Å
c = 10.175 (2) Å
α = 74.600 (17)°
β = 70.575 (16)°
γ = 61.829 (15)°
V = 823.4 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 298 (2) K
0.5 × 0.5 × 0.25 mm

Data collection

Stoe IPDSII diffractometer
Absorption correction: numerical; shape of crystal determined optically (X-RED and X-SHAPE; Stoe & Cie, 2002 ) T_min = 0.889, T_max = 0.949
8123 measured reflections
3801 independent reflections
3493 reflections with I > 2σ(I)
R_int = 0.045

Refinement

R[F² > 2σ(F²)] = 0.046
wR(F²) = 0.126
S = 1.03
3801 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002); 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 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808009239/hk2449sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808009239/hk2449Isup2.hkl

checkCIF report

Comment top

Quinoline nucleus is a backbone of many natural products and pharmacologicallly significant compounds displaying a broad range of biological activities and many functionalized quinolines are widely used as antimalarial, antiasthmatic, antiinflamatory, antibacterial, antihypertensive and tyrosine kinase PDGF-RTK inhibiting agents (Kalluraya & Sreenivasa, 1998; Doube et al., 1998; Maguire et al., 1994). We report herein the synthesis and crystal structure of the title compound, (I).

In the molecule of the title compound, (I), (Fig. 1) the bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings A (C1-C6), B (N1/C1/C6-C8/C15) and C (C16-C21) are, of course, planar, and they are oriented at dihedral angles of A/B = 0.88 (3)°, A/C = 76.76 (4)° and B/C = 77.64 (3)°. So, rings A and B are also nearly coplanar. The dihedral angle between the coplanar ring system and ring C is 77.21 (3)°.

In the crystal structure, the weak π–π interactions between the two adjacent A rings and A and B rings, with centroid-centroid distances of 3.7414 (11) Å and 3.8633 (12) Å, may be effective in the stabilization of the structure (Fig. 2).

Related literature top

For general background, see: Kalluraya & Sreenivasa (1998); Doube et al. (1998); Maguire et al. (1994). For bond-length data, see: Allen et al. (1987).

Experimental top

A mixture of 2-amino-5-chlorophenyl(phenyl)methanone (0.23 g, 1 mmol), cyclooctanone (1.26 g, 1 mmol) and Dewax-50 W ion exchange resin (0.3 g) was heated at 353 K. After 2 h the reaction mixture was washed with ethyl acetate (10 ml). Evaporation of the solvent followed by recrystallization from ethanol to afford the pure product (yield; 0.278 g, 75%).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED (Stoe & Cie, 2002); 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

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A packing diagram of (I).

2-Chloro-12-phenyl-6,7,8,9,10,11-hexahydrocycloocta[b]quinoline top

Crystal data top

C₂₁H₂₀ClN	Z = 2
M_r = 321.83	F(000) = 340
Triclinic, P1	D_x = 1.298 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.837 (2) Å	Cell parameters from 2086 reflections
b = 9.980 (2) Å	θ = 2.4–28.0°
c = 10.175 (2) Å	µ = 0.23 mm⁻¹
α = 74.600 (17)°	T = 298 K
β = 70.575 (16)°	Block, colorless
γ = 61.829 (15)°	0.5 × 0.5 × 0.25 mm
V = 823.4 (3) Å³

Data collection top

Stoe IPDSII diffractometer	3493 reflections with I > 2σ(I)
rotation method scans	R_int = 0.045
Absorption correction: numerical shape of crystal determined optically [PROGRAM NAME? reference?	θ_max = 28.0°, θ_min = 2.4°
T_min = 0.889, T_max = 0.949	h = −12→11
8123 measured reflections	k = −13→10
3801 independent reflections	l = −13→13

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.046	w = 1/[σ²(F_o²) + (0.0607P)² + 0.1883P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.126	(Δ/σ)_max = 0.006
S = 1.04	Δρ_max = 0.25 e Å⁻³
3801 reflections	Δρ_min = −0.19 e Å⁻³
208 parameters

Crystal data top

C₂₁H₂₀ClN	γ = 61.829 (15)°
M_r = 321.83	V = 823.4 (3) Å³
Triclinic, P1	Z = 2
a = 9.837 (2) Å	Mo Kα radiation
b = 9.980 (2) Å	µ = 0.23 mm⁻¹
c = 10.175 (2) Å	T = 298 K
α = 74.600 (17)°	0.5 × 0.5 × 0.25 mm
β = 70.575 (16)°

Data collection top

Stoe IPDSII diffractometer	3801 independent reflections
Absorption correction: numerical shape of crystal determined optically [PROGRAM NAME? reference?	3493 reflections with I > 2σ(I)
T_min = 0.889, T_max = 0.949	R_int = 0.045
8123 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.046	0 restraints
wR(F²) = 0.126	H-atom parameters constrained
S = 1.04	Δρ_max = 0.25 e Å⁻³
3801 reflections	Δρ_min = −0.19 e Å⁻³
208 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.

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

	x	y	z	U_iso*/U_eq
Cl1	0.59962 (5)	0.96565 (4)	0.17975 (4)	0.06276 (16)
N1	0.51106 (12)	0.54812 (13)	0.69575 (11)	0.0391 (2)
C1	0.53821 (13)	0.64045 (14)	0.57445 (12)	0.0354 (2)
C2	0.42557 (15)	0.79582 (15)	0.56208 (15)	0.0440 (3)
H2	0.3377	0.8313	0.6366	0.053*
C3	0.44417 (16)	0.89348 (15)	0.44312 (16)	0.0462 (3)
H3	0.3693	0.9949	0.4354	0.055*
C4	0.57823 (15)	0.83909 (14)	0.33177 (14)	0.0418 (3)
C5	0.69071 (14)	0.69125 (14)	0.33901 (13)	0.0392 (3)
H5	0.7787	0.659	0.2639	0.047*
C6	0.67271 (13)	0.58733 (13)	0.46148 (12)	0.0333 (2)
C7	0.78256 (13)	0.43037 (13)	0.47776 (12)	0.0339 (2)
C8	0.75403 (14)	0.33702 (14)	0.60027 (12)	0.0357 (2)
C9	0.86347 (17)	0.16885 (15)	0.62161 (14)	0.0456 (3)
H9A	0.9111	0.1313	0.531	0.055*
H9B	0.8003	0.1139	0.6796	0.055*
C10	0.99695 (16)	0.13077 (18)	0.69016 (16)	0.0542 (4)
H10A	1.0455	0.0207	0.7167	0.065*
H10B	1.0777	0.1584	0.62	0.065*
C11	0.94953 (18)	0.2078 (2)	0.81886 (16)	0.0549 (4)
H11A	0.9085	0.3178	0.7909	0.066*
H11B	1.0445	0.1765	0.8501	0.066*
C12	0.82614 (19)	0.17430 (19)	0.94328 (16)	0.0553 (4)
H12A	0.8568	0.1606	1.0289	0.066*
H12B	0.8289	0.078	0.936	0.066*
C13	0.65535 (18)	0.29655 (18)	0.95684 (14)	0.0510 (3)
H13A	0.6551	0.3948	0.9529	0.061*
H13B	0.5927	0.2748	1.0491	0.061*
C14	0.57222 (16)	0.31198 (17)	0.84728 (14)	0.0470 (3)
H14A	0.5988	0.2101	0.8307	0.056*
H14B	0.4582	0.3605	0.8855	0.056*
C15	0.61401 (13)	0.40276 (14)	0.70838 (12)	0.0370 (3)
C16	0.92569 (13)	0.37293 (13)	0.35925 (12)	0.0359 (2)
C17	0.91195 (17)	0.34403 (19)	0.23968 (14)	0.0498 (3)
H17	0.8139	0.3575	0.2335	0.06*
C18	1.0449 (2)	0.2949 (2)	0.12879 (17)	0.0655 (5)
H18	1.0355	0.2746	0.0489	0.079*
C19	1.1906 (2)	0.2758 (2)	0.13600 (18)	0.0631 (4)
H19	1.2792	0.2421	0.0617	0.076*
C20	1.20421 (17)	0.30678 (19)	0.25315 (18)	0.0564 (4)
H20	1.302	0.2955	0.2578	0.068*
C21	1.07270 (15)	0.35483 (16)	0.36480 (15)	0.0453 (3)
H21	1.083	0.3752	0.4442	0.054*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0600 (3)	0.0434 (2)	0.0641 (3)	−0.01716 (17)	−0.01096 (18)	0.01044 (16)
N1	0.0288 (5)	0.0426 (5)	0.0396 (5)	−0.0107 (4)	−0.0059 (4)	−0.0076 (4)
C1	0.0271 (5)	0.0369 (6)	0.0400 (6)	−0.0093 (4)	−0.0084 (4)	−0.0094 (4)
C2	0.0304 (6)	0.0392 (6)	0.0524 (7)	−0.0063 (5)	−0.0053 (5)	−0.0130 (5)
C3	0.0367 (6)	0.0334 (6)	0.0607 (8)	−0.0071 (5)	−0.0131 (6)	−0.0078 (5)
C4	0.0396 (6)	0.0357 (6)	0.0486 (7)	−0.0157 (5)	−0.0132 (5)	−0.0006 (5)
C5	0.0327 (6)	0.0376 (6)	0.0426 (6)	−0.0123 (5)	−0.0068 (5)	−0.0059 (5)
C6	0.0268 (5)	0.0346 (5)	0.0377 (5)	−0.0102 (4)	−0.0084 (4)	−0.0083 (4)
C7	0.0277 (5)	0.0358 (6)	0.0366 (5)	−0.0095 (4)	−0.0080 (4)	−0.0096 (4)
C8	0.0318 (5)	0.0346 (6)	0.0391 (6)	−0.0103 (4)	−0.0104 (4)	−0.0074 (4)
C9	0.0475 (7)	0.0333 (6)	0.0455 (7)	−0.0086 (5)	−0.0103 (5)	−0.0065 (5)
C10	0.0372 (7)	0.0478 (7)	0.0542 (8)	−0.0030 (6)	−0.0116 (6)	0.0008 (6)
C11	0.0457 (7)	0.0622 (9)	0.0552 (8)	−0.0218 (7)	−0.0207 (6)	0.0034 (7)
C12	0.0548 (8)	0.0573 (9)	0.0470 (7)	−0.0206 (7)	−0.0186 (6)	0.0057 (6)
C13	0.0531 (8)	0.0526 (8)	0.0366 (6)	−0.0188 (6)	−0.0069 (5)	−0.0013 (5)
C14	0.0372 (6)	0.0509 (7)	0.0463 (7)	−0.0197 (6)	−0.0053 (5)	−0.0001 (6)
C15	0.0301 (5)	0.0413 (6)	0.0387 (6)	−0.0142 (5)	−0.0091 (4)	−0.0050 (5)
C16	0.0308 (5)	0.0325 (5)	0.0378 (6)	−0.0083 (4)	−0.0052 (4)	−0.0085 (4)
C17	0.0420 (7)	0.0655 (9)	0.0450 (7)	−0.0231 (6)	−0.0054 (5)	−0.0178 (6)
C18	0.0635 (10)	0.0914 (13)	0.0468 (8)	−0.0362 (9)	0.0029 (7)	−0.0309 (8)
C19	0.0472 (8)	0.0739 (11)	0.0574 (9)	−0.0243 (8)	0.0123 (7)	−0.0265 (8)
C20	0.0323 (6)	0.0617 (9)	0.0695 (9)	−0.0167 (6)	−0.0022 (6)	−0.0190 (7)
C21	0.0348 (6)	0.0471 (7)	0.0513 (7)	−0.0118 (5)	−0.0087 (5)	−0.0152 (6)

Geometric parameters (Å, º) top

C1—N1	1.3612 (16)	C11—H11A	0.97
C1—C6	1.4153 (16)	C11—H11B	0.97
C1—C2	1.4194 (17)	C12—C13	1.526 (2)
C2—C3	1.358 (2)	C12—H12A	0.97
C2—H2	0.93	C12—H12B	0.97
C3—C4	1.4051 (19)	C13—C14	1.527 (2)
C3—H3	0.93	C13—H13A	0.97
C4—C5	1.3644 (18)	C13—H13B	0.97
C4—Cl1	1.7405 (14)	C14—C15	1.5075 (18)
C5—C6	1.4143 (17)	C14—H14A	0.97
C5—H5	0.93	C14—H14B	0.97
C6—C7	1.4255 (16)	C15—N1	1.3217 (17)
C7—C8	1.3777 (17)	C16—C17	1.3836 (18)
C7—C16	1.4969 (16)	C16—C21	1.3890 (18)
C8—C15	1.4353 (17)	C17—C18	1.390 (2)
C8—C9	1.5096 (17)	C17—H17	0.93
C9—C10	1.534 (2)	C18—C19	1.378 (3)
C9—H9A	0.97	C18—H18	0.93
C9—H9B	0.97	C19—C20	1.370 (2)
C10—C11	1.521 (2)	C19—H19	0.93
C10—H10A	0.97	C20—C21	1.3857 (19)
C10—H10B	0.97	C20—H20	0.93
C11—C12	1.524 (2)	C21—H21	0.93

N1—C1—C6	122.66 (11)	H11A—C11—H11B	107.4
N1—C1—C2	117.98 (11)	C11—C12—C13	115.65 (13)
C6—C1—C2	119.36 (11)	C11—C12—H12A	108.4
C3—C2—C1	121.00 (12)	C13—C12—H12A	108.4
C3—C2—H2	119.5	C11—C12—H12B	108.4
C1—C2—H2	119.5	C13—C12—H12B	108.4
C2—C3—C4	119.00 (12)	H12A—C12—H12B	107.4
C2—C3—H3	120.5	C12—C13—C14	116.62 (13)
C4—C3—H3	120.5	C12—C13—H13A	108.1
C5—C4—C3	122.25 (12)	C14—C13—H13A	108.1
C5—C4—Cl1	119.37 (10)	C12—C13—H13B	108.1
C3—C4—Cl1	118.37 (10)	C14—C13—H13B	108.1
C4—C5—C6	119.61 (11)	H13A—C13—H13B	107.3
C4—C5—H5	120.2	C15—C14—C13	114.79 (11)
C6—C5—H5	120.2	C15—C14—H14A	108.6
C5—C6—C1	118.77 (11)	C13—C14—H14A	108.6
C5—C6—C7	123.61 (10)	C15—C14—H14B	108.6
C1—C6—C7	117.63 (11)	C13—C14—H14B	108.6
C8—C7—C6	119.53 (10)	H14A—C14—H14B	107.5
C8—C7—C16	122.32 (10)	N1—C15—C8	123.17 (11)
C6—C7—C16	118.15 (10)	N1—C15—C14	114.02 (11)
C7—C8—C15	118.28 (11)	C8—C15—C14	122.80 (11)
C7—C8—C9	121.86 (11)	C17—C16—C21	118.98 (11)
C15—C8—C9	119.85 (11)	C17—C16—C7	120.43 (11)
C8—C9—C10	115.07 (12)	C21—C16—C7	120.52 (11)
C8—C9—H9A	108.5	C16—C17—C18	119.87 (13)
C10—C9—H9A	108.5	C16—C17—H17	120.1
C8—C9—H9B	108.5	C18—C17—H17	120.1
C10—C9—H9B	108.5	C19—C18—C17	120.65 (15)
H9A—C9—H9B	107.5	C19—C18—H18	119.7
C11—C10—C9	116.56 (12)	C17—C18—H18	119.7
C11—C10—H10A	108.2	C20—C19—C18	119.70 (13)
C9—C10—H10A	108.2	C20—C19—H19	120.2
C11—C10—H10B	108.2	C18—C19—H19	120.1
C9—C10—H10B	108.2	C19—C20—C21	120.16 (14)
H10A—C10—H10B	107.3	C19—C20—H20	119.9
C10—C11—C12	116.04 (14)	C21—C20—H20	119.9
C10—C11—H11A	108.3	C20—C21—C16	120.63 (13)
C12—C11—H11A	108.3	C20—C21—H21	119.7
C10—C11—H11B	108.3	C16—C21—H21	119.7
C12—C11—H11B	108.3	C15—N1—C1	118.73 (10)

N1—C1—C2—C3	−178.99 (12)	C10—C11—C12—C13	−98.63 (17)
C6—C1—C2—C3	0.70 (19)	C11—C12—C13—C14	70.55 (19)
C1—C2—C3—C4	−0.6 (2)	C12—C13—C14—C15	−80.42 (17)
C2—C3—C4—C5	0.0 (2)	C7—C8—C15—N1	0.29 (18)
C2—C3—C4—Cl1	179.69 (11)	C9—C8—C15—N1	−178.45 (11)
C3—C4—C5—C6	0.7 (2)	C7—C8—C15—C14	−179.14 (11)
Cl1—C4—C5—C6	−179.07 (9)	C9—C8—C15—C14	2.13 (18)
C4—C5—C6—C1	−0.59 (18)	C13—C14—C15—N1	−96.60 (14)
C4—C5—C6—C7	178.98 (11)	C13—C14—C15—C8	82.88 (16)
N1—C1—C6—C5	179.60 (10)	C8—C7—C16—C17	103.88 (15)
C2—C1—C6—C5	−0.07 (17)	C6—C7—C16—C17	−75.90 (16)
N1—C1—C6—C7	0.00 (17)	C8—C7—C16—C21	−79.21 (16)
C2—C1—C6—C7	−179.67 (11)	C6—C7—C16—C21	101.02 (14)
C5—C6—C7—C8	−179.10 (11)	C21—C16—C17—C18	1.2 (2)
C1—C6—C7—C8	0.48 (16)	C7—C16—C17—C18	178.19 (15)
C5—C6—C7—C16	0.69 (17)	C16—C17—C18—C19	−0.6 (3)
C1—C6—C7—C16	−179.74 (10)	C17—C18—C19—C20	−0.5 (3)
C6—C7—C8—C15	−0.62 (17)	C18—C19—C20—C21	1.0 (3)
C16—C7—C8—C15	179.61 (10)	C19—C20—C21—C16	−0.3 (2)
C6—C7—C8—C9	178.09 (11)	C17—C16—C21—C20	−0.8 (2)
C16—C7—C8—C9	−1.68 (18)	C7—C16—C21—C20	−177.74 (13)
C7—C8—C9—C10	91.27 (15)	C8—C15—N1—C1	0.19 (18)
C15—C8—C9—C10	−90.04 (15)	C14—C15—N1—C1	179.66 (10)
C8—C9—C10—C11	46.24 (18)	C6—C1—N1—C15	−0.33 (18)
C9—C10—C11—C12	59.62 (18)	C2—C1—N1—C15	179.34 (11)

Experimental details

Crystal data
Chemical formula	C₂₁H₂₀ClN
M_r	321.83
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	9.837 (2), 9.980 (2), 10.175 (2)
α, β, γ (°)	74.600 (17), 70.575 (16), 61.829 (15)
V (Å³)	823.4 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.23
Crystal size (mm)	0.5 × 0.5 × 0.25

Data collection
Diffractometer	Stoe IPDSII diffractometer
Absorption correction	Numerical shape of crystal determined optically [PROGRAM NAME? reference?
T_min, T_max	0.889, 0.949
No. of measured, independent and observed [I > 2σ(I)] reflections	8123, 3801, 3493
R_int	0.045
(sin θ/λ)_max (Å⁻¹)	0.659

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.046, 0.126, 1.04
No. of reflections	3801
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.19

Computer programs: X-AREA (Stoe & Cie, 2002), X-RED (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Acknowledgements

The author is grateful to the Islamic Azad University, Dorood Branch, for financial support.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Doube, D., Blouin, M., Brideau, C., Chan, C., Desmarais, S., Eithier, D., Falgueyert, J. P., Friesen, R. W., Girrard, M., Girrard, J., Tagari, P. & Yang, R. N. (1998). Bioorg. Med. Chem. Lett. 8, 1255–1260. Web of Science PubMed Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Kalluraya, B. & Sreenivasa, S. (1998). Il Farmaco, 53, 399–404. Web of Science CrossRef CAS PubMed Google Scholar
Maguire, M. P., Sheets, K. R., Mevety, K., Spada, A. P. & Ziberstein, A. (1994). J. Med. Chem. 37, 2129–2137. CrossRef CAS PubMed Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (2002). X-AREA, X-RED and X-SHAPE. Stoe & Cie, Darmstadt, Germany. Google Scholar