Structural characterization of [1,4]diazepino[6,5-b]indoles by powder diffraction

As part of a systematic structural study of potentially pharmacologically active [1,4]diazepino[6,5-b]indoles, the crystal structures of nine compounds have been determined from laboratory powder diffraction data. The investigated compounds are: 2-oxo-1-(4-nitrophenyl)-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₇H₁₂N₄O₄ (1a); 2-oxo-1-phenyl-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₇H₁₃N₃O₂ (1b); 2-oxo-1-(4-ethoxyphenyl)-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₉H₁₇N₃O₃ (1c); 2-oxo-1-(4-chlorophenyl)-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₇H₁₂N₃O₂Cl (1d); 2-oxo-1-(4-cyanophenyl)-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₈H₁₂N₄O₂ (1e); 6-methyl-2-oxo-1-phenyl-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole-4-oxide, C₁₈H₁₅N₃O₂ (1f); 2-formyl-3-[N′-(ω-chloracetyl)-N′-(4-nitrophenyl)]aminoindole, C₁₇H₁₂N₃O₄Cl (2a); 2-formyl-3-[N′-(ω-chloracetyl)-N′-(4-nitrophenyl)]aminoindole solvate with toluene (2:1), C₁₇H₁₂N₃O₄Cl·0.5C₇H₈ (2as); 2-formyl-3-[N′-(ω-chloracetyl)-N′-(4-cyanophenyl)]aminoindole, C₁₈H₁₂N₃O₂Cl (2e). Compounds (1a)–(1f) crystallize in non-centrosymmetric triclinic, monoclinic and orthorhombic space groups. The three-dimensional structures of (1a)–(1e) demonstrate identical intermolecular NH(indole)...O←N hydrogen bonds, which form linear chains of connected molecules. A comparison of the crystal structures (2a), (2e) and (2as) shows that the solvent used in the re-crystallization of (2a) and (2e), which are intermediates in the synthesis of (1a) and (1e), affects the intermolecular hydrogen-bond formation and, as a result, leads to essentially different yields of the goal products.

Computing details

Data collection: Johannson LS18 linescanner data collection program; cell refinement: LSPAID (Visser et al., 1986); data reduction: local program; program(s) used to solve structure: MRIA (Chernyshev & Zlokazov, 1992); program(s) used to refine structure: MRIA; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: MRIA, SHELXL93 (Sheldrick, 1997), PARST (Nardelli, 1995).

Figures

2-Oxo-1-phenyl-1,2,3,6-tetrahydro[1,4]diazepino[6,5-b]indole- 4-oxide

Crystal data

C17H13N3O2	Dx = 1.395 Mg m^−3
Mr = 291.30	Melting point: 282-283 C K
Orthorhombic, P212121	Cu Kα1 radiation, λ = 1.54059 Å
a = 23.97 (2) Å	µ = 0.77 mm^−1
b = 10.609 (8) Å	T = 295 K
c = 5.457 (3) Å	Particle morphology: needles
V = 1387.0 (17) Å^3	pale yellow
Z = 4	flat_sheet, 7 × 7 mm
F(000) = 608

Data collection

Enraf-Nonius Guinier Johannson camera FR 552 diffractometer	Specimen mounting: pressed as a thin layer in the specimen holder of the camera
Radiation source: Fine focus X-ray tube, Nonius 3502.223	Data collection mode: transmission
Quartz monochromator	Scan method: Stationary detector

Refinement

Refinement on Inet	120 parameters
Least-squares matrix: full with fixed elements per cycle	95 restraints
Rp = 0.088	21 constraints
Rwp = 0.118	H atoms treated by a mixture of independent and constrained refinement
Rexp = 0.040	Weighting scheme based on measured s.u.'s
χ^2 = 8.679	(Δ/σ)max = 0.032
6901 data points	Background function: Chebyshev polynomial up to the 5th order
Profile function: split-type pseudo-Voigt (Toraya, 1986)	Preferred orientation correction: Symmetrized harmonics expansion up to the 6th order (Ahtee et al., 1989, (Jarvinen, 1993)

Special details

Experimental. specimen was rotated in its plane

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 (Ų)

	x	y	z	Uiso*/Ueq
C11	0.8705 (4)	0.7791 (8)	0.8016 (16)	0.053 (2)*
C9	0.8031 (3)	0.8642 (9)	1.0901 (13)	0.053 (2)*
C7	0.8374 (4)	1.0002 (7)	0.7592 (16)	0.053 (2)*
C10	0.8358 (4)	0.7651 (8)	1.0135 (17)	0.053 (2)*
C8	0.8034 (3)	0.9817 (8)	0.9645 (18)	0.053 (2)*
C13	0.8713 (3)	0.8972 (8)	0.6837 (15)	0.053 (2)*
C12	0.9096 (4)	0.6984 (7)	0.6746 (16)	0.053 (2)*
C14	0.9300 (3)	0.7683 (8)	0.4714 (15)	0.053 (2)*
N6	0.9067 (3)	0.8895 (6)	0.4825 (13)	0.053 (2)*
N1	0.9227 (3)	0.5715 (6)	0.7259 (14)	0.053 (2)*
C5	0.9694 (4)	0.7336 (7)	0.2886 (17)	0.053 (2)*
N4	1.0126 (3)	0.6574 (6)	0.3393 (12)	0.053 (2)*
C2	0.9748 (4)	0.5142 (7)	0.6674 (15)	0.053 (2)*
C3	1.0197 (4)	0.6060 (9)	0.5915 (15)	0.053 (2)*
O15	1.0475 (2)	0.6164 (4)	0.1744 (9)	0.053 (2)*
O16	0.9802 (2)	0.3977 (5)	0.6573 (9)	0.053 (2)*
C17	0.8804 (4)	0.4883 (7)	0.8345 (18)	0.053 (2)*
C18	0.8927 (4)	0.4171 (9)	1.0478 (16)	0.053 (2)*
C19	0.8528 (4)	0.3386 (8)	1.1426 (16)	0.053 (2)*
C20	0.7974 (4)	0.3382 (9)	1.0478 (17)	0.053 (2)*
C21	0.7857 (4)	0.4095 (9)	0.8375 (16)	0.053 (2)*
C22	0.8266 (4)	0.4854 (8)	0.7333 (18)	0.053 (2)*
H9	0.7803	0.8538	1.2264	0.050*
H7	0.8378	1.0769	0.6761	0.050*
H10	0.8353	0.6896	1.1000	0.050*
H8	0.7807	1.0466	1.0189	0.050*
H6	0.9132	0.9495	0.3803	0.050*
H5	0.9651	0.7648	0.1307	0.050*
H31	1.0556	0.5640	0.6015	0.050*
H32	1.0201	0.6756	0.7067	0.050*
H18	0.9274	0.4236	1.1224	0.050*
H19	0.8620	0.2847	1.2708	0.050*
H20	0.7695	0.2915	1.1239	0.050*
H21	0.7503	0.4059	0.7673	0.050*
H22	0.8183	0.5342	0.5965	0.050*

Geometric parameters (Å, º)

C11—C13	1.411 (14)	C5—N4	1.343 (12)
C11—C10	1.428 (14)	C5—H5	0.93
C11—C12	1.446 (14)	N4—O15	1.303 (10)
C9—C10	1.376 (14)	N4—C3	1.492 (12)
C9—C8	1.423 (14)	C2—O16	1.242 (12)
C9—H9	0.93	C2—C3	1.514 (14)
C7—C8	1.403 (14)	C3—H31	0.97
C7—C13	1.419 (14)	C3—H32	0.97
C7—H7	0.93	C17—C22	1.394 (14)
C10—H10	0.93	C17—C18	1.418 (14)
C8—H8	0.93	C18—C19	1.377 (14)
C13—N6	1.398 (12)	C18—H18	0.93
C12—N1	1.411 (12)	C19—C20	1.423 (14)
C12—C14	1.422 (14)	C19—H19	0.93
C14—N6	1.403 (13)	C20—C21	1.399 (14)
C14—C5	1.419 (14)	C20—H20	0.93
N6—H6	0.86	C21—C22	1.401 (14)
N1—C2	1.426 (12)	C21—H21	0.93
N1—C17	1.464 (12)	C22—H22	0.93
C13—C11—C10	118.0 (9)	C14—C5—H5	119
C13—C11—C12	107.4 (8)	O15—N4—C5	123.9 (8)
C10—C11—C12	134.6 (9)	O15—N4—C3	116.1 (7)
C10—C9—C8	121.2 (9)	C5—N4—C3	119.8 (8)
C10—C9—H9	119	O16—C2—N1	121.8 (9)
C8—C9—H9	119	O16—C2—C3	123.4 (9)
C8—C7—C13	116.9 (9)	N1—C2—C3	114.5 (8)
C8—C7—H7	122	N4—C3—C2	114.0 (8)
C13—C7—H7	121	N4—C3—H31	109
C9—C10—C11	119.9 (9)	C2—C3—H31	109
C9—C10—H10	120	N4—C3—H32	109
C11—C10—H10	120	C2—C3—H32	109
C7—C8—C9	120.9 (9)	H31—C3—H32	108
C7—C8—H8	120	C22—C17—C18	120.2 (9)
C9—C8—H8	120	C22—C17—N1	119.3 (8)
N6—C13—C11	108.4 (8)	C18—C17—N1	120.4 (8)
N6—C13—C7	128.5 (9)	C19—C18—C17	119.1 (9)
C11—C13—C7	123.0 (9)	C19—C18—H18	120
N1—C12—C14	125.0 (8)	C17—C18—H18	120
N1—C12—C11	128.0 (8)	C18—C19—C20	121.0 (9)
C14—C12—C11	106.9 (8)	C18—C19—H19	119
N6—C14—C5	121.7 (9)	C20—C19—H19	120
N6—C14—C12	108.0 (8)	C21—C20—C19	119.0 (9)
C5—C14—C12	130.2 (9)	C21—C20—H20	121
C13—N6—C14	109.2 (7)	C19—C20—H20	121
C13—N6—H6	125	C20—C21—C22	120.0 (9)
C14—N6—H6	125	C20—C21—H21	120
C12—N1—C2	123.9 (8)	C22—C21—H21	120
C12—N1—C17	119.9 (8)	C17—C22—C21	120.3 (9)
C2—N1—C17	116.2 (7)	C17—C22—H22	120
N4—C5—C14	121.5 (9)	C21—C22—H22	120
N4—C5—H5	119