Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106020567/av3014sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106020567/av3014Isup2.hkl |
CCDC reference: 616147
A solution of benzoyl chloride (0.4 ml, 3.0 mmol) in CCl4 (5.0 ml) and a solution of triethylamine (0.6 ml, 4.5 mmol) in CCl4 (5.0 ml) were simultaneously added to a suspension of piroxicam (0.99 g, 3.0 mmol) in dry CCl4 (9.0 ml), dropwise, under a nitrogen atmosphere during cooling in an ice bath. The mixture was then stirred at room temperature under a nitrogen atmosphere for 5 h. The solvent was evaporated in vacuo and the residue was treated according to a standard procedure to obtain crude product (1.27 g, 86% purity, HPLC). The product was recrystallized from ethyl acetate to give pure (I) [m.p. 421–423 K (literature 418–421 K; Boneschans et al., 2003)].
All H atoms were located in a difference Fourier synthesis and then treated as riding atoms, with C—H distances of 0.93 (aromatic) and 0.96 Å (CH3), an N—H distance of 0.86 Å, and Uiso(H) values of 1.2Ueq(C,N), or 1.5Ueq(C) for the methyl group.
Data collection: STADI4 (Stoe & Cie, 1997); cell refinement: STADI4; data reduction: X-RED (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997), PowderCell (Kraus & Nolze, 1999) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999), SHELXL97 and X-RED.
C22H17N3O5S | F(000) = 904 |
Mr = 435.46 | Dx = 1.404 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 60 reflections |
a = 11.106 (3) Å | θ = 10.0–14.6° |
b = 16.5606 (16) Å | µ = 0.20 mm−1 |
c = 12.0351 (18) Å | T = 295 K |
β = 111.463 (12)° | Block, colourless |
V = 2060.0 (7) Å3 | 0.42 × 0.34 × 0.23 mm |
Z = 4 |
Stoe Stadi04 four-circle diffractometer | 2544 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.055 |
Planar graphite monochromator | θmax = 27.5°, θmin = 2.1° |
Scan width (ω) = 1.40 – 1.70, scan ratio 2θ:ω = 1.00 I(Net) and σ(I) calculated according to Blessing (1987) | h = −14→14 |
Absorption correction: ψ scan (X-RED; Stoe & Cie, 1997) | k = −21→21 |
Tmin = 0.900, Tmax = 0.956 | l = −15→15 |
9810 measured reflections | 3 standard reflections every 180 min |
4717 independent reflections | intensity decay: 3.8% |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.062 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0353P)2 + 0.7359P] where P = (Fo2 + 2Fc2)/3 |
4717 reflections | (Δ/σ)max < 0.001 |
331 parameters | Δρmax = 0.17 e Å−3 |
17 restraints | Δρmin = −0.25 e Å−3 |
C22H17N3O5S | V = 2060.0 (7) Å3 |
Mr = 435.46 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.106 (3) Å | µ = 0.20 mm−1 |
b = 16.5606 (16) Å | T = 295 K |
c = 12.0351 (18) Å | 0.42 × 0.34 × 0.23 mm |
β = 111.463 (12)° |
Stoe Stadi04 four-circle diffractometer | 2544 reflections with I > 2σ(I) |
Absorption correction: ψ scan (X-RED; Stoe & Cie, 1997) | Rint = 0.055 |
Tmin = 0.900, Tmax = 0.956 | 3 standard reflections every 180 min |
9810 measured reflections | intensity decay: 3.8% |
4717 independent reflections |
R[F2 > 2σ(F2)] = 0.062 | 17 restraints |
wR(F2) = 0.135 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.17 e Å−3 |
4717 reflections | Δρmin = −0.25 e Å−3 |
331 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. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) 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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.2358 (3) | 0.48883 (18) | 0.1038 (3) | 0.0494 (7) | |
C2 | 0.2468 (3) | 0.50437 (17) | 0.2169 (3) | 0.0527 (8) | |
C3 | 0.3429 (4) | 0.5822 (2) | 0.4075 (3) | 0.0764 (11) | |
H3 | 0.2690 | 0.5737 | 0.4250 | 0.092* | |
C4 | 0.4450 (5) | 0.6259 (3) | 0.4846 (4) | 0.0922 (13) | |
H4 | 0.4396 | 0.6454 | 0.5551 | 0.111* | |
C5 | 0.5536 (4) | 0.6414 (2) | 0.4609 (3) | 0.0833 (11) | |
H5 | 0.6192 | 0.6731 | 0.5129 | 0.100* | |
C6 | 0.5661 (3) | 0.6098 (2) | 0.3595 (3) | 0.0652 (9) | |
H6 | 0.6409 | 0.6188 | 0.3435 | 0.078* | |
C7 | 0.4660 (3) | 0.56487 (19) | 0.2824 (3) | 0.0515 (8) | |
C8 | 0.3514 (3) | 0.55057 (18) | 0.3024 (3) | 0.0536 (8) | |
C9 | 0.2889 (3) | 0.5997 (2) | −0.0067 (3) | 0.0645 (9) | |
H9A | 0.2879 | 0.6424 | 0.0469 | 0.097* | |
H9B | 0.2037 | 0.5930 | −0.0659 | 0.097* | |
H9C | 0.3484 | 0.6129 | −0.0451 | 0.097* | |
C10 | 0.1356 (3) | 0.43567 (19) | 0.0185 (3) | 0.0515 (7) | |
C11 | 0.0919 (3) | 0.36330 (17) | −0.1738 (3) | 0.0491 (7) | |
C12 | −0.0136 (3) | 0.3184 (2) | −0.1751 (3) | 0.0748 (11) | |
H12 | −0.0448 | 0.3217 | −0.1134 | 0.090* | |
C13 | −0.0709 (4) | 0.2682 (2) | −0.2724 (4) | 0.0898 (13) | |
H13 | −0.1412 | 0.2364 | −0.2758 | 0.108* | |
C14 | −0.0254 (4) | 0.2651 (2) | −0.3621 (3) | 0.0820 (12) | |
H14 | −0.0628 | 0.2312 | −0.4273 | 0.098* | |
C15 | 0.0767 (4) | 0.3130 (2) | −0.3542 (3) | 0.0739 (10) | |
H15 | 0.1068 | 0.3117 | −0.4169 | 0.089* | |
C16 | 0.1426 (3) | 0.3985 (2) | 0.2798 (3) | 0.0515 (8) | |
C17 | 0.0267 (3) | 0.38078 (18) | 0.3067 (2) | 0.0476 (7) | |
C18 | −0.0474 (3) | 0.4403 (2) | 0.3306 (3) | 0.0585 (8) | |
H18 | −0.0224 | 0.4941 | 0.3342 | 0.070* | |
C19 | −0.1595 (3) | 0.4193 (3) | 0.3490 (3) | 0.0754 (11) | |
H19 | −0.2099 | 0.4591 | 0.3651 | 0.091* | |
C20 | −0.1958 (4) | 0.3402 (3) | 0.3435 (3) | 0.0815 (12) | |
H20 | −0.2720 | 0.3266 | 0.3543 | 0.098* | |
C21 | −0.1218 (4) | 0.2808 (2) | 0.3224 (3) | 0.0783 (11) | |
H21 | −0.1468 | 0.2271 | 0.3202 | 0.094* | |
C22 | −0.0105 (3) | 0.3007 (2) | 0.3045 (3) | 0.0632 (9) | |
H22 | 0.0404 | 0.2602 | 0.2907 | 0.076* | |
N1 | 0.3299 (2) | 0.52371 (15) | 0.0613 (2) | 0.0472 (6) | |
N2 | 0.1633 (2) | 0.41425 (15) | −0.0791 (2) | 0.0533 (6) | |
H2 | 0.2329 | 0.4344 | −0.0832 | 0.064* | |
N3 | 0.1364 (3) | 0.36181 (16) | −0.2627 (2) | 0.0613 (7) | |
O1 | 0.55872 (19) | 0.56614 (15) | 0.11303 (19) | 0.0672 (6) | |
O2 | 0.5092 (2) | 0.43495 (14) | 0.1837 (2) | 0.0678 (6) | |
O3 | 0.0409 (2) | 0.41227 (15) | 0.0370 (2) | 0.0698 (7) | |
O4 | 0.1528 (2) | 0.47894 (12) | 0.2598 (2) | 0.0599 (6) | |
O5 | 0.2212 (2) | 0.35046 (14) | 0.2756 (2) | 0.0708 (7) | |
S1 | 0.47932 (7) | 0.51799 (5) | 0.15678 (7) | 0.0531 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0418 (16) | 0.0547 (19) | 0.0584 (19) | 0.0011 (14) | 0.0262 (14) | −0.0031 (15) |
C2 | 0.0552 (18) | 0.0500 (19) | 0.067 (2) | 0.0009 (15) | 0.0396 (16) | 0.0003 (15) |
C3 | 0.096 (3) | 0.080 (3) | 0.069 (2) | −0.010 (2) | 0.048 (2) | −0.018 (2) |
C4 | 0.118 (4) | 0.102 (3) | 0.062 (2) | −0.019 (3) | 0.040 (2) | −0.028 (2) |
C5 | 0.091 (3) | 0.090 (3) | 0.061 (2) | −0.020 (2) | 0.019 (2) | −0.020 (2) |
C6 | 0.062 (2) | 0.071 (2) | 0.055 (2) | −0.0069 (18) | 0.0132 (17) | −0.0037 (18) |
C7 | 0.0530 (18) | 0.0542 (19) | 0.0471 (18) | −0.0005 (15) | 0.0182 (15) | −0.0011 (15) |
C8 | 0.064 (2) | 0.0518 (19) | 0.0522 (19) | −0.0008 (16) | 0.0298 (16) | −0.0038 (15) |
C9 | 0.060 (2) | 0.072 (2) | 0.061 (2) | −0.0074 (17) | 0.0224 (17) | 0.0056 (18) |
C10 | 0.0380 (16) | 0.0565 (19) | 0.062 (2) | 0.0013 (14) | 0.0208 (14) | 0.0001 (16) |
C11 | 0.0447 (16) | 0.0394 (16) | 0.0555 (19) | −0.0016 (13) | 0.0093 (14) | 0.0029 (14) |
C12 | 0.074 (2) | 0.075 (3) | 0.074 (3) | −0.027 (2) | 0.025 (2) | 0.000 (2) |
C13 | 0.088 (3) | 0.082 (3) | 0.083 (3) | −0.045 (2) | 0.012 (2) | 0.008 (2) |
C14 | 0.101 (3) | 0.065 (2) | 0.061 (2) | −0.023 (2) | 0.006 (2) | 0.0005 (19) |
C15 | 0.079 (3) | 0.071 (2) | 0.064 (2) | −0.009 (2) | 0.0172 (19) | −0.012 (2) |
C16 | 0.0481 (18) | 0.058 (2) | 0.0511 (18) | 0.0041 (15) | 0.0211 (15) | 0.0010 (15) |
C17 | 0.0474 (17) | 0.0515 (18) | 0.0467 (17) | 0.0011 (14) | 0.0205 (14) | 0.0026 (14) |
C18 | 0.061 (2) | 0.062 (2) | 0.062 (2) | 0.0117 (17) | 0.0329 (17) | 0.0126 (17) |
C19 | 0.064 (2) | 0.096 (3) | 0.078 (3) | 0.019 (2) | 0.040 (2) | 0.016 (2) |
C20 | 0.060 (2) | 0.115 (4) | 0.081 (3) | −0.016 (2) | 0.039 (2) | 0.005 (2) |
C21 | 0.079 (3) | 0.080 (3) | 0.084 (3) | −0.027 (2) | 0.039 (2) | −0.011 (2) |
C22 | 0.063 (2) | 0.063 (2) | 0.067 (2) | −0.0048 (17) | 0.0266 (17) | −0.0043 (18) |
N1 | 0.0399 (13) | 0.0579 (15) | 0.0482 (14) | −0.0061 (12) | 0.0212 (11) | −0.0033 (13) |
N2 | 0.0442 (14) | 0.0582 (16) | 0.0620 (17) | −0.0095 (12) | 0.0246 (12) | −0.0091 (13) |
N3 | 0.0590 (16) | 0.0630 (18) | 0.0613 (17) | −0.0083 (14) | 0.0214 (14) | −0.0142 (15) |
O1 | 0.0505 (12) | 0.0901 (17) | 0.0691 (15) | −0.0226 (12) | 0.0314 (11) | −0.0152 (13) |
O2 | 0.0604 (14) | 0.0615 (15) | 0.0817 (16) | 0.0123 (11) | 0.0263 (12) | −0.0062 (12) |
O3 | 0.0476 (13) | 0.0938 (18) | 0.0765 (16) | −0.0157 (12) | 0.0326 (12) | −0.0052 (13) |
O4 | 0.0687 (14) | 0.0530 (13) | 0.0797 (15) | −0.0003 (11) | 0.0528 (12) | −0.0022 (12) |
O5 | 0.0614 (14) | 0.0674 (16) | 0.0943 (18) | 0.0165 (12) | 0.0411 (13) | 0.0080 (13) |
S1 | 0.0415 (4) | 0.0642 (5) | 0.0575 (5) | −0.0044 (4) | 0.0224 (3) | −0.0090 (4) |
C1—C2 | 1.346 (4) | C12—H12 | 0.9300 |
C1—N1 | 1.442 (3) | C13—C14 | 1.350 (5) |
C1—C10 | 1.494 (4) | C13—H13 | 0.9300 |
C2—O4 | 1.388 (3) | C14—C15 | 1.359 (5) |
C2—C8 | 1.456 (4) | C14—H14 | 0.9300 |
C3—C4 | 1.379 (5) | C15—N3 | 1.331 (4) |
C3—C8 | 1.404 (4) | C15—H15 | 0.9300 |
C3—H3 | 0.9300 | C16—O5 | 1.196 (3) |
C4—C5 | 1.362 (5) | C16—O4 | 1.366 (3) |
C4—H4 | 0.9300 | C16—C17 | 1.467 (4) |
C5—C6 | 1.381 (5) | C17—C18 | 1.380 (4) |
C5—H5 | 0.9300 | C17—C22 | 1.387 (4) |
C6—C7 | 1.377 (4) | C18—C19 | 1.385 (4) |
C6—H6 | 0.9300 | C18—H18 | 0.9300 |
C7—C8 | 1.399 (4) | C19—C20 | 1.366 (5) |
C7—S1 | 1.753 (3) | C19—H19 | 0.9300 |
C9—N1 | 1.478 (4) | C20—C21 | 1.364 (5) |
C9—H9A | 0.9600 | C20—H20 | 0.9300 |
C9—H9B | 0.9600 | C21—C22 | 1.370 (4) |
C9—H9C | 0.9600 | C21—H21 | 0.9300 |
C10—O3 | 1.216 (3) | C22—H22 | 0.9300 |
C10—N2 | 1.365 (4) | N1—S1 | 1.639 (2) |
C11—N3 | 1.333 (4) | N2—H2 | 0.8600 |
C11—C12 | 1.383 (4) | O1—S1 | 1.425 (2) |
C11—N2 | 1.406 (4) | O2—S1 | 1.424 (2) |
C12—C13 | 1.386 (5) | ||
C2—C1—N1 | 118.2 (3) | C13—C14—C15 | 118.0 (4) |
C2—C1—C10 | 125.2 (3) | C13—C14—H14 | 121.0 |
N1—C1—C10 | 116.5 (3) | C15—C14—H14 | 121.0 |
C1—C2—O4 | 121.0 (3) | N3—C15—C14 | 124.2 (4) |
C1—C2—C8 | 124.7 (3) | N3—C15—H15 | 117.9 |
O4—C2—C8 | 114.3 (3) | C14—C15—H15 | 117.9 |
C4—C3—C8 | 119.5 (4) | O5—C16—O4 | 122.2 (3) |
C4—C3—H3 | 120.2 | O5—C16—C17 | 126.1 (3) |
C8—C3—H3 | 120.2 | O4—C16—C17 | 111.7 (3) |
C5—C4—C3 | 122.1 (4) | C18—C17—C22 | 119.4 (3) |
C5—C4—H4 | 118.9 | C18—C17—C16 | 122.8 (3) |
C3—C4—H4 | 118.9 | C22—C17—C16 | 117.8 (3) |
C4—C5—C6 | 119.8 (4) | C17—C18—C19 | 119.6 (3) |
C4—C5—H5 | 120.1 | C17—C18—H18 | 120.2 |
C6—C5—H5 | 120.1 | C19—C18—H18 | 120.2 |
C7—C6—C5 | 118.8 (3) | C20—C19—C18 | 119.9 (3) |
C7—C6—H6 | 120.6 | C20—C19—H19 | 120.0 |
C5—C6—H6 | 120.6 | C18—C19—H19 | 120.0 |
C6—C7—C8 | 122.5 (3) | C19—C20—C21 | 120.9 (3) |
C6—C7—S1 | 121.2 (2) | C19—C20—H20 | 119.5 |
C8—C7—S1 | 116.3 (2) | C21—C20—H20 | 119.5 |
C7—C8—C3 | 117.2 (3) | C20—C21—C22 | 119.8 (4) |
C7—C8—C2 | 120.5 (3) | C20—C21—H21 | 120.1 |
C3—C8—C2 | 122.3 (3) | C22—C21—H21 | 120.1 |
N1—C9—H9A | 109.5 | C21—C22—C17 | 120.4 (3) |
N1—C9—H9B | 109.5 | C21—C22—H22 | 119.8 |
H9A—C9—H9B | 109.5 | C17—C22—H22 | 119.8 |
N1—C9—H9C | 109.5 | C1—N1—C9 | 114.8 (2) |
H9A—C9—H9C | 109.5 | C1—N1—S1 | 114.02 (19) |
H9B—C9—H9C | 109.5 | C9—N1—S1 | 117.71 (19) |
O3—C10—N2 | 123.8 (3) | C10—N2—C11 | 128.0 (2) |
O3—C10—C1 | 122.6 (3) | C10—N2—H2 | 116.0 |
N2—C10—C1 | 113.5 (2) | C11—N2—H2 | 116.0 |
N3—C11—C12 | 122.8 (3) | C11—N3—C15 | 117.2 (3) |
N3—C11—N2 | 113.4 (3) | C16—O4—C2 | 118.9 (2) |
C12—C11—N2 | 123.8 (3) | O2—S1—O1 | 120.03 (14) |
C11—C12—C13 | 117.3 (4) | O2—S1—N1 | 107.88 (13) |
C11—C12—H12 | 121.4 | O1—S1—N1 | 108.24 (13) |
C13—C12—H12 | 121.4 | O2—S1—C7 | 108.51 (14) |
C14—C13—C12 | 120.5 (3) | O1—S1—C7 | 109.26 (14) |
C14—C13—H13 | 119.8 | N1—S1—C7 | 101.29 (13) |
C12—C13—H13 | 119.8 | ||
N1—C1—C2—O4 | 174.0 (2) | C17—C18—C19—C20 | 0.0 (5) |
C10—C1—C2—O4 | −8.1 (5) | C18—C19—C20—C21 | 1.3 (6) |
N1—C1—C2—C8 | −3.5 (4) | C19—C20—C21—C22 | −1.1 (6) |
C10—C1—C2—C8 | 174.4 (3) | C20—C21—C22—C17 | −0.5 (6) |
C8—C3—C4—C5 | 1.7 (7) | C18—C17—C22—C21 | 1.8 (5) |
C3—C4—C5—C6 | −3.0 (7) | C16—C17—C22—C21 | −176.4 (3) |
C4—C5—C6—C7 | 1.8 (6) | C2—C1—N1—C9 | −96.7 (3) |
C5—C6—C7—C8 | 0.6 (5) | C10—C1—N1—C9 | 85.2 (3) |
C5—C6—C7—S1 | −176.1 (3) | C2—C1—N1—S1 | 43.4 (3) |
C6—C7—C8—C3 | −1.8 (5) | C10—C1—N1—S1 | −134.7 (2) |
S1—C7—C8—C3 | 175.1 (3) | O3—C10—N2—C11 | 0.0 (5) |
C6—C7—C8—C2 | 178.5 (3) | C1—C10—N2—C11 | 177.9 (3) |
S1—C7—C8—C2 | −4.7 (4) | N3—C11—N2—C10 | 172.6 (3) |
C4—C3—C8—C7 | 0.7 (5) | C12—C11—N2—C10 | −7.9 (5) |
C4—C3—C8—C2 | −179.6 (3) | C12—C11—N3—C15 | −1.6 (5) |
C1—C2—C8—C7 | −16.5 (5) | N2—C11—N3—C15 | 177.9 (3) |
O4—C2—C8—C7 | 165.9 (3) | C14—C15—N3—C11 | −0.2 (5) |
C1—C2—C8—C3 | 163.8 (3) | O5—C16—O4—C2 | 9.2 (5) |
O4—C2—C8—C3 | −13.9 (4) | C17—C16—O4—C2 | −171.1 (3) |
C2—C1—C10—O3 | 12.9 (5) | C1—C2—O4—C16 | 71.3 (4) |
N1—C1—C10—O3 | −169.1 (3) | C8—C2—O4—C16 | −111.0 (3) |
C2—C1—C10—N2 | −165.1 (3) | C1—N1—S1—O2 | 58.5 (2) |
N1—C1—C10—N2 | 12.9 (4) | C9—N1—S1—O2 | −162.6 (2) |
N3—C11—C12—C13 | 2.2 (5) | C1—N1—S1—O1 | −170.2 (2) |
N2—C11—C12—C13 | −177.3 (3) | C9—N1—S1—O1 | −31.3 (2) |
C11—C12—C13—C14 | −1.0 (6) | C1—N1—S1—C7 | −55.3 (2) |
C12—C13—C14—C15 | −0.6 (6) | C9—N1—S1—C7 | 83.6 (2) |
C13—C14—C15—N3 | 1.3 (6) | C6—C7—S1—O2 | 100.0 (3) |
O5—C16—C17—C18 | 168.3 (3) | C8—C7—S1—O2 | −76.9 (3) |
O4—C16—C17—C18 | −11.3 (4) | C6—C7—S1—O1 | −32.5 (3) |
O5—C16—C17—C22 | −13.5 (5) | C8—C7—S1—O1 | 150.5 (2) |
O4—C16—C17—C22 | 166.9 (3) | C6—C7—S1—N1 | −146.6 (3) |
C22—C17—C18—C19 | −1.6 (5) | C8—C7—S1—N1 | 36.5 (3) |
C16—C17—C18—C19 | 176.6 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···O1i | 0.86 | 2.47 | 3.275 (3) | 157 |
C5—H5···O5ii | 0.93 | 2.54 | 3.244 (5) | 132 |
C13—H13···O5iii | 0.93 | 2.34 | 3.240 (4) | 163 |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, −y+1, −z+1; (iii) x−1/2, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C22H17N3O5S |
Mr | 435.46 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 295 |
a, b, c (Å) | 11.106 (3), 16.5606 (16), 12.0351 (18) |
β (°) | 111.463 (12) |
V (Å3) | 2060.0 (7) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.20 |
Crystal size (mm) | 0.42 × 0.34 × 0.23 |
Data collection | |
Diffractometer | Stoe Stadi04 four-circle diffractometer |
Absorption correction | ψ scan (X-RED; Stoe & Cie, 1997) |
Tmin, Tmax | 0.900, 0.956 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9810, 4717, 2544 |
Rint | 0.055 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.062, 0.135, 1.09 |
No. of reflections | 4717 |
No. of parameters | 331 |
No. of restraints | 17 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.17, −0.25 |
Computer programs: STADI4 (Stoe & Cie, 1997), STADI4, X-RED (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), PowderCell (Kraus & Nolze, 1999) and Mercury (Macrae et al., 2006), WinGX (Farrugia, 1999), SHELXL97 and X-RED.
C2—O4 | 1.388 (3) | N1—S1 | 1.639 (2) |
C10—O3 | 1.216 (3) | O1—S1 | 1.425 (2) |
C16—O5 | 1.196 (3) | O2—S1 | 1.424 (2) |
C16—O4 | 1.366 (3) | ||
C16—O4—C2 | 118.9 (2) | N1—S1—C7 | 101.29 (13) |
O2—S1—O1 | 120.03 (14) | ||
C2—C1—C10—O3 | 12.9 (5) | C1—C2—O4—C16 | 71.3 (4) |
C1—C10—N2—C11 | 177.9 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2···O1i | 0.86 | 2.47 | 3.275 (3) | 157 |
C5—H5···O5ii | 0.93 | 2.54 | 3.244 (5) | 132 |
C13—H13···O5iii | 0.93 | 2.34 | 3.240 (4) | 163 |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, −y+1, −z+1; (iii) x−1/2, −y+1/2, z−1/2. |
Piroxicam, 4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide, is a non-steroidal anti-inflammatory and analgesic drug belonging to a new class of compounds called oxicams (Hirai et al., 1997, Khalil et al., 2000). Besides great therapeutic potential, oxicams are very interesting polyfunctional chemical compounds by virtue of their dynamic structural features, which include tautomeric switches and their possible polymorphism (Banerjee & Sarkar, 2002). Piroxicam benzoate, (I), was synthesized by an acylation reaction from piroxicam and benzoyl chloride (Boneschans et al., 2003). This acyl piroxicam derivative proved to be useful in therapy as a non-steroidal anti-inflammatory agent (Lombardino, 1982). Compound (I) has been characterized by elemental analysis, IR spectroscopy, HPLC and thermal analysis (melting point) (Boneschans et al., 2003; Lombardino, 1982), but its crystal structure has not been solved until now. The structure of a compound of similar composition, 4-ethoxy-2- methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide, (II), which contains an ethoxy group is instead of a benzoyloxy group, was solved by Hammen et al. (1989).
We have synthesized piroxicam benzoate according to a modified procedure and have studied the crystalline structure. Single crystals of (I), grown from ethyl acetate, are monoclinic (space groups P21/n, Z = 4), with an asymmetric unit containing one molecule (Fig. 1). Selected geometric parameters of the molecule are listed in Table 1. The geometric parameters of the piroxicam group in (I) are similar to those in β-piroxicam. The C2—O4 bond length in (I) is the greatest among those of polymorphs of piroxicam [ranging from 1.339 (15) to 1.350 (9) Å; Kojic-Prodic & Ruzic-Toros, 1982, Reck et al., 1988] or the monohydrate of piroxicam [ranging from 1.268 (5) to 1.279 (5) Å; Bordner et al., 1984, Reck et al., 1988], but is close to that in (II) [1.377 (7) Å; Hammen et al., 1989]. Conversely, the C10—O3 bond length is somewhat shorter than those in other piroxicam-based structures [ranging from 1.223 (7) to 1.262 (10) Å]. Despite the fact that only one O atom the SO2 group is involved in hydrogen bonding, the S1—O1 and S1—O2 bond lengths are identical within the limits of experimental errors, as is the case for β-piroxicam (Kojic-Prodic & Ruzic-Toros, 1982). In piroxicam monohydrate and (II), these lengths differ from one another, and the greatest difference is found in α-piroxicam [1.465 (14) and 1.406 (10) Å; Reck et al., 1988]. There are remarkable differences in the C2—C1—C10—O3 torsion angle (Table 1). This angle is about −177° in piroxicam monohydrate and (II), but 6.0 (5) and 1(2)° in β- and α-piroxicam, respectively. In piroxicam benzoate, atom O3 is on the same side of the molecule as atom O4, but the N2/H2 group is on the opposite side. This fact is very important, because atom N2 is involved in hydrogen bonding. The angle between the planes of the C3–C8 and C17–C22 rings in (I) is 53.3 (1)°.
The molecules of (I) are linked together by paired N—H···O hydrogen bonds (Table 2), forming a centrosymmetric R22(14) dimer (Fig. 2). Similar dimers are observed in β-piroxicam. The structure of α-piroxicam is formed by uncoupled molecules. There is an infinite three-dimensional framework of N—H···O and C—H···O hydrogen bonds in piroxicam monohydrate, with water molecules playing an important role in bonding. In turn, in (II), there are no conventional hydrogen bonds, only intramolecular N—H···O ones.
The molecules in (I) are linked into a three-dimensional framework by C—H···O bonds, in which atom O5 accepts bonds from the C5/H5 group of the benzyl ring and the C13/H13 group of the pyridine ring in two neighbouring molecules (Fig. 3 and Table 2). The molecules are packed in a herringbone structure, with O5 as the site of junction.
Among the remaining short distances between atoms belonging to different molecules, the C—H···N contacts involving atom N3 of the pyridine ring are very interesting. This atom appears to be the site of a junction between three molecules. The C21/H21 group in the molecule at (1/2 + x, 1/2 − y, −1/2 + z) is at a C21iv···N3 distance of 3.439 (5) Å (H21iv···N3 = 2.68 Å and C21iv—H21iv···N3 = 139°) and the C18/H18 group in the molecule at (−x, 1 − y, −z) is at a C18v···N3 distance of 3.434 (4) Å (H18v···N3 = 2.69 Å and C18v—H18v···N3 = 138°). The parameters of the C—H···N contacts are identical within the limits of experimental errors, but they are not related to one another via symmetry. The C—H···N contacts form an infinite two-dimensional-framework.