Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101006175/na1513sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101006175/na1513Isup2.hkl |
CCDC reference: 169949
The compound was obtained from LABORATORIOS GADOR. Crystals suitable for X-ray diffraction were obtained through slow evaporation from water solution.
The positional parameters of the H atoms were constrained to have C—H distances of 0.96 Å for primary, 0.97 Å for secondary, and 0.93 Å for aromatic H atoms. The H atoms were treated as riding and their isotropic thermal parameters were constrained to be 1.2 times larger than those of their hosts (1.5 for methyl groups). Data collection was performed at the Laboratorio Nacional de Difracción (LANADI).
Data collection: CAD-4-PC (Enraf Nonius, 1993); cell refinement: CAD-4-PC; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: PARST (Nardelli, 1995), CSD (Allen et al., 1983) and WinGX (Farrugia, 1999).
Fig. 1. View of the structure showing the numbering scheme used and displacement ellipsoids drawn at 30% probability. |
C20H17ClN2O3 | Dx = 1.403 Mg m−3 |
Mr = 368.81 | Melting point: 455 K |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 8.6326 (9) Å | Cell parameters from 25 reflections |
b = 13.119 (1) Å | θ = 10–20° |
c = 15.505 (4) Å | µ = 0.24 mm−1 |
β = 96.19 (1)° | T = 293 K |
V = 1745.7 (5) Å3 | Prism, colourless |
Z = 4 | 0.36 × 0.2 × 0.14 mm |
F(000) = 768 |
CAD4 diffractometer | Rint = 0.031 |
ω–2θ scans | θmax = 25°, θmin = 2.0° |
Absorption correction: numerical integration (Sheldrick, 1976) | h = −10→10 |
Tmin = 0.91, Tmax = 0.94 | k = −1→15 |
3493 measured reflections | l = 0→18 |
3071 independent reflections | 2 standard reflections every 98 reflections |
1551 reflections with I > 2σ(I) | intensity decay: <2% |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.046 | w = 1/[σ2(Fo2) + (0.0369P)2 + 0.9696P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.132 | (Δ/σ)max < 0.001 |
S = 1.07 | Δρmax = 0.22 e Å−3 |
3071 reflections | Δρmin = −0.24 e Å−3 |
235 parameters |
C20H17ClN2O3 | V = 1745.7 (5) Å3 |
Mr = 368.81 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.6326 (9) Å | µ = 0.24 mm−1 |
b = 13.119 (1) Å | T = 293 K |
c = 15.505 (4) Å | 0.36 × 0.2 × 0.14 mm |
β = 96.19 (1)° |
CAD4 diffractometer | 1551 reflections with I > 2σ(I) |
Absorption correction: numerical integration (Sheldrick, 1976) | Rint = 0.031 |
Tmin = 0.91, Tmax = 0.94 | 2 standard reflections every 98 reflections |
3493 measured reflections | intensity decay: <2% |
3071 independent reflections |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.22 e Å−3 |
3071 reflections | Δρmin = −0.24 e Å−3 |
235 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.0413 (2) | 0.31121 (17) | −0.17074 (14) | 0.0406 (6) | |
O4 | −0.0803 (3) | 0.0213 (2) | −0.14088 (19) | 0.0619 (8) | |
O7 | 0.3936 (3) | −0.0127 (2) | −0.09127 (18) | 0.0631 (8) | |
N5 | 0.0977 (3) | 0.1480 (2) | −0.11214 (17) | 0.0392 (7) | |
N8 | 0.4486 (3) | 0.1530 (2) | −0.06120 (18) | 0.0443 (7) | |
C2 | −0.0752 (4) | 0.2699 (3) | −0.2273 (2) | 0.0430 (9) | |
C3 | −0.1081 (4) | 0.1718 (3) | −0.2243 (2) | 0.0461 (9) | |
H3 | −0.1826 | 0.1445 | −0.2657 | 0.055* | |
C4 | −0.0314 (4) | 0.1053 (3) | −0.1583 (2) | 0.0458 (9) | |
C6 | 0.1877 (4) | 0.0886 (3) | −0.0445 (2) | 0.0457 (9) | |
H6B | 0.1368 | 0.0236 | −0.0378 | 0.055* | |
H6A | 0.1917 | 0.1248 | 0.0103 | 0.055* | |
C7 | 0.3524 (4) | 0.0705 (3) | −0.0671 (2) | 0.0467 (9) | |
C8 | 0.6064 (4) | 0.1430 (4) | −0.0865 (3) | 0.0686 (13) | |
H8C | 0.6224 | 0.0744 | −0.1051 | 0.103* | |
H8B | 0.6808 | 0.1588 | −0.0378 | 0.103* | |
H8A | 0.6194 | 0.1892 | −0.1332 | 0.103* | |
C9 | 0.4007 (4) | 0.2487 (3) | −0.0313 (2) | 0.0403 (8) | |
C10 | 0.4911 (4) | 0.3002 (3) | 0.0345 (2) | 0.0514 (10) | |
H10 | 0.5854 | 0.2722 | 0.0578 | 0.062* | |
C11 | 0.4437 (4) | 0.3913 (3) | 0.0655 (2) | 0.0543 (11) | |
H11 | 0.5062 | 0.4258 | 0.1085 | 0.065* | |
C12 | 0.3031 (4) | 0.4311 (3) | 0.0324 (2) | 0.0473 (9) | |
C13 | 0.2120 (4) | 0.3836 (3) | −0.0330 (2) | 0.0407 (9) | |
H13 | 0.1169 | 0.4121 | −0.0544 | 0.049* | |
C14 | 0.2610 (4) | 0.2926 (2) | −0.0677 (2) | 0.0349 (8) | |
C15 | 0.1648 (3) | 0.2412 (3) | −0.1429 (2) | 0.0362 (8) | |
C16 | 0.2586 (3) | 0.2249 (3) | −0.2203 (2) | 0.0347 (8) | |
C17 | 0.2796 (4) | 0.1313 (3) | −0.2568 (2) | 0.0464 (9) | |
H17 | 0.2349 | 0.0737 | −0.2346 | 0.056* | |
C18 | 0.3667 (4) | 0.1218 (3) | −0.3261 (3) | 0.0620 (12) | |
H18 | 0.3821 | 0.0579 | −0.3497 | 0.074* | |
C19 | 0.4300 (5) | 0.2061 (4) | −0.3601 (3) | 0.0654 (12) | |
H19 | 0.488 | 0.1996 | −0.407 | 0.078* | |
C20 | 0.4083 (4) | 0.2997 (3) | −0.3255 (3) | 0.0617 (12) | |
H20 | 0.4509 | 0.3571 | −0.349 | 0.074* | |
C21 | 0.3234 (4) | 0.3092 (3) | −0.2558 (2) | 0.0507 (10) | |
H21 | 0.3093 | 0.3734 | −0.2323 | 0.061* | |
C22 | −0.1521 (4) | 0.3485 (3) | −0.2865 (2) | 0.0597 (11) | |
H22C | −0.2339 | 0.3174 | −0.3244 | 0.09* | |
H22B | −0.0767 | 0.378 | −0.3203 | 0.09* | |
H22A | −0.1951 | 0.4008 | −0.2529 | 0.09* | |
Cl1 | 0.23773 (14) | 0.54380 (9) | 0.07470 (7) | 0.0750 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0346 (12) | 0.0436 (14) | 0.0422 (13) | 0.0111 (11) | −0.0026 (11) | 0.0006 (11) |
O4 | 0.0481 (16) | 0.0479 (17) | 0.089 (2) | −0.0120 (14) | 0.0039 (14) | 0.0032 (15) |
O7 | 0.0612 (17) | 0.0491 (17) | 0.077 (2) | 0.0150 (14) | 0.0010 (14) | 0.0026 (15) |
N5 | 0.0331 (15) | 0.0408 (17) | 0.0432 (17) | −0.0019 (14) | 0.0020 (13) | 0.0064 (14) |
N8 | 0.0341 (16) | 0.0487 (19) | 0.0498 (18) | 0.0080 (15) | 0.0027 (13) | 0.0110 (15) |
C2 | 0.0284 (18) | 0.066 (3) | 0.0343 (19) | 0.0053 (18) | 0.0037 (15) | 0.0013 (19) |
C3 | 0.0331 (19) | 0.059 (3) | 0.046 (2) | −0.0071 (18) | −0.0007 (16) | −0.003 (2) |
C4 | 0.035 (2) | 0.050 (2) | 0.053 (2) | 0.0003 (19) | 0.0092 (18) | −0.006 (2) |
C6 | 0.045 (2) | 0.045 (2) | 0.047 (2) | −0.0006 (18) | 0.0029 (17) | 0.0128 (18) |
C7 | 0.042 (2) | 0.049 (2) | 0.047 (2) | 0.008 (2) | −0.0024 (17) | 0.0123 (19) |
C8 | 0.040 (2) | 0.080 (3) | 0.088 (3) | 0.015 (2) | 0.016 (2) | 0.009 (3) |
C9 | 0.0327 (18) | 0.047 (2) | 0.0420 (19) | −0.0006 (17) | 0.0058 (16) | 0.0085 (17) |
C10 | 0.039 (2) | 0.071 (3) | 0.042 (2) | −0.006 (2) | −0.0032 (17) | 0.008 (2) |
C11 | 0.054 (2) | 0.068 (3) | 0.040 (2) | −0.018 (2) | 0.0019 (19) | −0.007 (2) |
C12 | 0.053 (2) | 0.053 (2) | 0.038 (2) | −0.008 (2) | 0.0136 (18) | −0.0070 (18) |
C13 | 0.0394 (19) | 0.046 (2) | 0.037 (2) | 0.0008 (17) | 0.0030 (16) | 0.0003 (17) |
C14 | 0.0340 (17) | 0.039 (2) | 0.0316 (17) | −0.0023 (16) | 0.0036 (14) | 0.0045 (16) |
C15 | 0.0289 (17) | 0.040 (2) | 0.0397 (18) | 0.0038 (16) | 0.0015 (15) | 0.0024 (17) |
C16 | 0.0298 (17) | 0.0382 (19) | 0.0352 (18) | 0.0020 (16) | −0.0003 (15) | 0.0019 (16) |
C17 | 0.046 (2) | 0.047 (2) | 0.047 (2) | −0.0007 (18) | 0.0064 (18) | −0.0071 (18) |
C18 | 0.059 (3) | 0.066 (3) | 0.062 (3) | 0.002 (2) | 0.011 (2) | −0.024 (2) |
C19 | 0.054 (3) | 0.093 (4) | 0.052 (3) | −0.003 (3) | 0.021 (2) | −0.011 (3) |
C20 | 0.062 (3) | 0.065 (3) | 0.062 (3) | −0.009 (2) | 0.024 (2) | 0.004 (2) |
C21 | 0.051 (2) | 0.049 (2) | 0.054 (2) | −0.0009 (19) | 0.0115 (19) | −0.002 (2) |
C22 | 0.052 (2) | 0.074 (3) | 0.051 (2) | 0.013 (2) | −0.0054 (19) | 0.004 (2) |
Cl1 | 0.0880 (8) | 0.0695 (7) | 0.0698 (7) | −0.0057 (6) | 0.0188 (6) | −0.0287 (6) |
O1—C2 | 1.372 (4) | C9—C14 | 1.399 (4) |
O1—C15 | 1.438 (4) | C10—C11 | 1.367 (5) |
O4—C4 | 1.221 (4) | C11—C12 | 1.369 (5) |
O7—C7 | 1.219 (4) | C12—C13 | 1.364 (5) |
N5—C4 | 1.377 (4) | C12—Cl1 | 1.736 (4) |
N5—C15 | 1.455 (4) | C13—C14 | 1.395 (4) |
N5—C6 | 1.462 (4) | C14—C15 | 1.515 (4) |
N8—C7 | 1.361 (4) | C15—C16 | 1.534 (4) |
N8—C9 | 1.416 (4) | C16—C17 | 1.372 (5) |
N8—C8 | 1.463 (4) | C16—C21 | 1.381 (5) |
C2—C3 | 1.320 (5) | C17—C18 | 1.382 (5) |
C2—C22 | 1.488 (5) | C18—C19 | 1.365 (6) |
C3—C4 | 1.449 (5) | C19—C20 | 1.360 (5) |
C6—C7 | 1.519 (5) | C20—C21 | 1.375 (5) |
C9—C10 | 1.390 (5) | ||
C2—O1—C15 | 114.1 (3) | C10—C11—C12 | 119.3 (4) |
C4—N5—C15 | 120.0 (3) | C13—C12—C11 | 121.4 (3) |
C4—N5—C6 | 119.7 (3) | C13—C12—Cl1 | 119.0 (3) |
C15—N5—C6 | 118.9 (3) | C11—C12—Cl1 | 119.7 (3) |
C7—N8—C9 | 122.0 (3) | C12—C13—C14 | 120.2 (3) |
C7—N8—C8 | 119.4 (3) | C13—C14—C9 | 118.7 (3) |
C9—N8—C8 | 118.7 (3) | C13—C14—C15 | 121.0 (3) |
C3—C2—O1 | 120.5 (3) | C9—C14—C15 | 120.3 (3) |
C3—C2—C22 | 127.9 (3) | O1—C15—N5 | 109.1 (2) |
O1—C2—C22 | 111.6 (3) | O1—C15—C14 | 105.9 (3) |
C2—C3—C4 | 121.9 (3) | N5—C15—C14 | 109.0 (3) |
O4—C4—N5 | 122.1 (4) | O1—C15—C16 | 107.0 (2) |
O4—C4—C3 | 123.8 (3) | N5—C15—C16 | 113.7 (3) |
N5—C4—C3 | 113.9 (3) | C14—C15—C16 | 111.8 (2) |
N5—C6—C7 | 110.9 (3) | C17—C16—C21 | 118.4 (3) |
O7—C7—N8 | 122.4 (3) | C17—C16—C15 | 123.5 (3) |
O7—C7—C6 | 121.5 (4) | C21—C16—C15 | 118.1 (3) |
N8—C7—C6 | 116.1 (3) | C16—C17—C18 | 120.5 (4) |
C10—C9—C14 | 119.2 (3) | C19—C18—C17 | 120.1 (4) |
C10—C9—N8 | 120.7 (3) | C20—C19—C18 | 120.1 (4) |
C14—C9—N8 | 120.1 (3) | C19—C20—C21 | 120.0 (4) |
C11—C10—C9 | 121.1 (4) | C20—C21—C16 | 120.9 (4) |
C15—O1—C2—C3 | 29.4 (4) | N8—C9—C14—C13 | 175.8 (3) |
C15—O1—C2—C22 | −151.3 (3) | C10—C9—C14—C15 | 176.5 (3) |
O1—C2—C3—C4 | 4.3 (5) | N8—C9—C14—C15 | −3.7 (4) |
C22—C2—C3—C4 | −174.9 (3) | C2—O1—C15—N5 | −50.8 (3) |
C15—N5—C4—O4 | 171.1 (3) | C2—O1—C15—C14 | −168.0 (2) |
C6—N5—C4—O4 | 5.0 (5) | C2—O1—C15—C16 | 72.6 (3) |
C15—N5—C4—C3 | −12.9 (4) | C4—N5—C15—O1 | 43.7 (4) |
C6—N5—C4—C3 | −179.0 (3) | C6—N5—C15—O1 | −150.2 (3) |
C2—C3—C4—O4 | 163.1 (4) | C4—N5—C15—C14 | 158.9 (3) |
C2—C3—C4—N5 | −12.8 (5) | C6—N5—C15—C14 | −35.0 (4) |
C4—N5—C6—C7 | 116.7 (3) | C4—N5—C15—C16 | −75.6 (3) |
C15—N5—C6—C7 | −49.4 (4) | C6—N5—C15—C16 | 90.6 (3) |
C9—N8—C7—O7 | −178.7 (3) | C13—C14—C15—O1 | 7.2 (4) |
C8—N8—C7—O7 | 1.4 (5) | C9—C14—C15—O1 | −173.3 (3) |
C9—N8—C7—C6 | 3.3 (5) | C13—C14—C15—N5 | −110.0 (3) |
C8—N8—C7—C6 | −176.7 (3) | C9—C14—C15—N5 | 69.5 (4) |
N5—C6—C7—O7 | −106.0 (4) | C13—C14—C15—C16 | 123.4 (3) |
N5—C6—C7—N8 | 72.0 (4) | C9—C14—C15—C16 | −57.1 (4) |
C7—N8—C9—C10 | 128.6 (4) | O1—C15—C16—C17 | −121.2 (3) |
C8—N8—C9—C10 | −51.5 (5) | N5—C15—C16—C17 | −0.8 (4) |
C7—N8—C9—C14 | −51.2 (4) | C14—C15—C16—C17 | 123.2 (3) |
C8—N8—C9—C14 | 128.7 (3) | O1—C15—C16—C21 | 57.8 (4) |
C14—C9—C10—C11 | 1.7 (5) | N5—C15—C16—C21 | 178.2 (3) |
N8—C9—C10—C11 | −178.1 (3) | C14—C15—C16—C21 | −57.8 (4) |
C9—C10—C11—C12 | 1.5 (5) | C21—C16—C17—C18 | 1.5 (5) |
C10—C11—C12—C13 | −2.4 (5) | C15—C16—C17—C18 | −179.5 (3) |
C10—C11—C12—Cl1 | 177.1 (3) | C16—C17—C18—C19 | −1.3 (6) |
C11—C12—C13—C14 | 0.0 (5) | C17—C18—C19—C20 | 0.4 (6) |
Cl1—C12—C13—C14 | −179.5 (2) | C18—C19—C20—C21 | 0.4 (6) |
C12—C13—C14—C9 | 3.2 (5) | C19—C20—C21—C16 | −0.3 (6) |
C12—C13—C14—C15 | −177.3 (3) | C17—C16—C21—C20 | −0.7 (5) |
C10—C9—C14—C13 | −4.0 (5) | C15—C16—C21—C20 | −179.8 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O4 | 0.97 | 2.33 | 2.760 (4) | 106 |
C8—H8C···O7 | 0.96 | 2.31 | 2.743 (5) | 106 |
C13—H13···O1 | 0.93 | 2.28 | 2.637 (4) | 102 |
C17—H17···N5 | 0.93 | 2.54 | 2.882 (4) | 102 |
C20—H20···O4i | 0.93 | 2.44 | 3.332 (5) | 161 |
C22—H22A···Cl1ii | 0.96 | 2.92 | 3.721 (4) | 142 |
C22—H22B···O7i | 0.96 | 2.63 | 3.578 (5) | 171 |
Symmetry codes: (i) −x+1/2, y+1/2, −z−1/2; (ii) −x, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C20H17ClN2O3 |
Mr | 368.81 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 8.6326 (9), 13.119 (1), 15.505 (4) |
β (°) | 96.19 (1) |
V (Å3) | 1745.7 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.24 |
Crystal size (mm) | 0.36 × 0.2 × 0.14 |
Data collection | |
Diffractometer | CAD4 diffractometer |
Absorption correction | Numerical integration (Sheldrick, 1976) |
Tmin, Tmax | 0.91, 0.94 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3493, 3071, 1551 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.132, 1.07 |
No. of reflections | 3071 |
No. of parameters | 235 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.24 |
Computer programs: CAD-4-PC (Enraf Nonius, 1993), CAD-4-PC, MolEN (Fair, 1990), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), PARST (Nardelli, 1995), CSD (Allen et al., 1983) and WinGX (Farrugia, 1999).
O1—C15 | 1.438 (4) | N8—C7 | 1.361 (4) |
O4—C4 | 1.221 (4) | N8—C9 | 1.416 (4) |
O7—C7 | 1.219 (4) | C6—C7 | 1.519 (5) |
N5—C4 | 1.377 (4) | C12—Cl1 | 1.736 (4) |
N5—C15 | 1.455 (4) | C14—C15 | 1.515 (4) |
N5—C6 | 1.462 (4) | C15—C16 | 1.534 (4) |
C4—N5—C15 | 120.0 (3) | O1—C15—N5 | 109.1 (2) |
C4—N5—C6 | 119.7 (3) | O1—C15—C14 | 105.9 (3) |
C15—N5—C6 | 118.9 (3) | N5—C15—C14 | 109.0 (3) |
C7—N8—C9 | 122.0 (3) | O1—C15—C16 | 107.0 (2) |
C7—N8—C8 | 119.4 (3) | N5—C15—C16 | 113.7 (3) |
C9—N8—C8 | 118.7 (3) | C14—C15—C16 | 111.8 (2) |
N5—C6—C7 | 110.9 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6B···O4 | 0.97 | 2.33 | 2.760 (4) | 106 |
C8—H8C···O7 | 0.96 | 2.31 | 2.743 (5) | 106 |
C13—H13···O1 | 0.93 | 2.28 | 2.637 (4) | 102 |
C17—H17···N5 | 0.93 | 2.54 | 2.882 (4) | 102 |
C20—H20···O4i | 0.93 | 2.44 | 3.332 (5) | 161 |
C22—H22A···Cl1ii | 0.96 | 2.92 | 3.721 (4) | 142 |
C22—H22B···O7i | 0.96 | 2.63 | 3.578 (5) | 171 |
Symmetry codes: (i) −x+1/2, y+1/2, −z−1/2; (ii) −x, −y+1, −z. |
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Many benzodiazepines are used as pharmacotherapy of several neurologic and psychiatric disorders because of their efficacy in the treatment of conditions involving a dysfunction of the GABAergic transmission in the central nervous system (Bradwejn, 1993; Gracies et al., 1997; Mohler, 1998; Nelson & Chouinard, 1999). The title compound, Ketazolam, (I), which is a benzodiazepine of the type possessing an additional fused heterocyclic ring, has proven safe and effective antispastic action (Basmajian et al., 1984) as well as effectiveness in the treatment of a variety of manifestations of anxiety (Fabre & Harris, 1976; Fabre et al., 1981). \sch
The crystal structure has previously been studied, the cell parameters have been reported (Szmuszkovicz et al., 1971) and deposited without any structural information in the Cambridge Structural Database (refcode CHMPOA) [CSD; Allen et al., 1983]; besides, in the final publication the crystal structure is not actually described. Despite the fact that in the CSD there is available information of 5-phenyl-1,4-benzodiazepines attaching an additional O-containing ring, none of these has an oxazine ring.
This work is part of our ongoing study on benzodiazepines and derived compounds (Vega et al., 1999) and was undertaken to give a detailed description of intra- and intermolecular features of a member of this family of drugs.
In the asymmetric unit of the title compound, the C15—C16 bond makes an angle of 85.3 (4)° with the plane through the oxazine ring so, as is apparent in Fig. 1, the phenyl ring protrudes axially from the tricyclic core of the molecule due to the sp3 character and tetrahedral angle configuration of the C15 carbon (see Table 1). The phenyl ring could be oriented around the C15—C16 bond in such a way either as to avoid a steric hindrance between H18 and H13 at 1/2 - x, y - 1/2, -z - 1/2 (distance H18···H13 2.42 Å) or as to maximize hydrogen bond interactions involving C20—H20···O4i and C17—H17···N5. The value of the N5—C15—C16—C17 torsion angle [-0.8 (4)°] indicates that the C16—C17 bond of the phenyl ring is coplanar with the C15—N5 bond of the core.
A geometrical descriptor common to benzodiazepines has been the dihedral angle between the phenyl and the benzo rings, ranging from 54 to 75° for 5-(unsubstituted)phenyl-1,4-benzodiazepines (Chananont et al., 1980; Hamor & Martin, 1983; Butcher & Hamor, 1985). In this work, the phenyl ring sustains a dihedral angle of 86.2 (1)° with the benzo ring, which exceeds by more than 10° the value cited in the literature.
The six-membered rings of the core, the oxazine heterocycle and the benzo ring, are fused to the N5—C15 side (d-face) and across the C9—C14 bond of the central diazepine ring, respectively. The former has a conformation intermediate between half-chair and sofa [the ring puckering parameters (Cremer & Pople, 1975) for the sequence C3,C2,O1,C15,N5,C4 are QT 0.427 (3) Å, θ2 63.8 (4)° and ϕ2 165.4 (5)°, and the asymmetry parameters (Nardelli, 1983) are Δ2(C3—C4) 0.061 (1) and Δs(C3) 0.069 (1)] whereas the latter is slightly deviated from planarity [maximum deviation from least-squares plane defined by C9,C10,C11,C12,C13,C14 and Cl1 of 0.038 (4) Å at C11].
The diazepine ring adopts a twist-boat conformation, the ring puckering parameters for the sequence N5,C15,C14,C9,N8,C7,C6 are QT 1.066 (3) Å, θ2 82.4 (2)°, ϕ2 92.6 (2)° and ϕ3 97 (1)°. The asymmetry parameters are Δs(C6) 0.114 (1) and Δ2(N5) 0.028 (1), i.e. with a local pseudo-twofold axis running along N5 and the mid-point of the C9—N8 bond corresponding to a twisted conformation. The asymmetry parameter is representative of the degree of departure from a boat-like conformation of the diazepine ring. By comparison, the Δs(C6) averages 0.009 (2) [four independent molecules] for such a ring in the benzodiazepine Alprazolam (Vega et al., 1999), hence showing a pseudosymmetry mirror plane passing through the bow atom and the midpoint of the opposite bond, i.e. the diazepine ring has an almost perfect boat conformation.
The amide bonds in the vicinity of C6 atom, N8—C7 and N5—C4, are affected by electron delocalization between the nitrogen lone pair and the carbonyl oxygen. The bond has a length about halfway between the C—N pure single- and double-bond distances and the valency angles at the N atoms are close to 120° (see table 1). The overall geometry of the C—N bonds resembles that of a normal double bond and their planar nature are illustrated by the values of the torsion angles of the sequences C15—N5—C4—O4 and C9—N8—C7—O7 [171.1 (3) and -178.7 (3)°, respectively].
The packing for the crystal involves the use of both keto O atoms and the halogen atom as hydrogen-bond acceptor sites in very weak intermolecular hydrogen bondings, the donors being methyl and aryl carbons (see Table 2). The C—H···O contacts determine chains of molecules running along the crystallographic b direction; meanwhile, parallel chains are held together by the C—H···Cl hydrogen bonds thus forming a layer of molecules, and the packing of a crystal of Ketazolam comprises the stacking of layers.