Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108014509/sk3236sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270108014509/sk3236Isup2.hkl |
CCDC reference: 692671
A mixture of 5-amino-3-(4-chlorophenyl-1H-pyrazole, (B) (1.9 mmol), and 1-(4-nitrophenyl)-propenone, (C) (1.9 mmol), in dimethylformamide (1 ml) was heated under reflux for 20 min to afford the intermediate, 2-(4-chlorophenyl)-5-(4-nitrophenyl)-4,7- dihydropyrazolo[1,5-a]pyrimidine, (A). The reaction mixture was cooled to ambient temperature and the intermediate was collected by filtration, washed with ethanol and dried, and then purified by chromatography on alumina using chloroform as the eluent. Phosphoryl chloride (2.1 mmol) was then added dropwise to a suspension of the pyrazolopyrimidine intermediate (1.0 mmol) in dimethylformamide (2 ml) at 273 K. When the addition had been completed the reaction mixture was stirred vigorously for 0.5 h at ambient temperature. The resulting solid product, (I), was collected by filtration, dried and recrystallized from dimethylformamide to give yellow crystals suitable for single-crystal X-ray diffraction (yield 65%, m.p. 555–557 K). Spectroscopic analysis: MS (m/z, %) 410/408 (35/100, M+), 407 (53), 361 (51), 350 (70), 102 (31), 75 (42), 40 (82).
The systematic absences permitted C2/c and Cc as possible space groups. C2/c was selected, and confirmed by the subsequent structure analysis. All H atoms were located in difference maps and then treated as riding atoms, with C—H = 0.99 (CH2) or 0.95 Å (all other H atoms) and N—H 0.88 Å, and with Uiso(H) = 1.2Ueq(parent).
Data collection: COLLECT (Nonius, 1999); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: OSCAIL (McArdle, 2003) and SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PRPKAPPA (Ferguson, 1999).
C20H13ClN4O4 | F(000) = 1680 |
Mr = 408.79 | Dx = 1.558 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 4002 reflections |
a = 23.943 (5) Å | θ = 3.8–27.5° |
b = 13.445 (2) Å | µ = 0.26 mm−1 |
c = 12.336 (5) Å | T = 120 K |
β = 118.594 (10)° | Block, colourless |
V = 3486.7 (17) Å3 | 0.46 × 0.36 × 0.24 mm |
Z = 8 |
Bruker Nonius KappaCCD area-detector diffractometer | 4002 independent reflections |
Radiation source: Bruker Nonius FR591 rotating anode | 2520 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.066 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.8° |
ϕ and ω scans | h = −31→31 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −17→16 |
Tmin = 0.891, Tmax = 0.941 | l = −16→15 |
40202 measured reflections |
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)] = 0.051 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.139 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0465P)2 + 9.8005P] where P = (Fo2 + 2Fc2)/3 |
4002 reflections | (Δ/σ)max = 0.001 |
262 parameters | Δρmax = 0.36 e Å−3 |
0 restraints | Δρmin = −0.43 e Å−3 |
C20H13ClN4O4 | V = 3486.7 (17) Å3 |
Mr = 408.79 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 23.943 (5) Å | µ = 0.26 mm−1 |
b = 13.445 (2) Å | T = 120 K |
c = 12.336 (5) Å | 0.46 × 0.36 × 0.24 mm |
β = 118.594 (10)° |
Bruker Nonius KappaCCD area-detector diffractometer | 4002 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2520 reflections with I > 2σ(I) |
Tmin = 0.891, Tmax = 0.941 | Rint = 0.066 |
40202 measured reflections |
R[F2 > 2σ(F2)] = 0.051 | 0 restraints |
wR(F2) = 0.139 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.36 e Å−3 |
4002 reflections | Δρmin = −0.43 e Å−3 |
262 parameters |
x | y | z | Uiso*/Ueq | ||
Cl24 | 0.57868 (3) | 0.28471 (6) | 1.23489 (6) | 0.0334 (2) | |
O31 | 0.37089 (10) | 0.53108 (15) | 0.53537 (17) | 0.0328 (5) | |
O61 | 0.20351 (9) | 0.04486 (13) | 0.23740 (17) | 0.0267 (4) | |
O541 | 0.06077 (10) | 0.47143 (16) | −0.24494 (19) | 0.0384 (5) | |
O542 | 0.14516 (11) | 0.45976 (17) | −0.26641 (19) | 0.0397 (6) | |
N1 | 0.37250 (10) | 0.20177 (16) | 0.63810 (19) | 0.0212 (5) | |
N4 | 0.30105 (10) | 0.35687 (16) | 0.37383 (18) | 0.0209 (5) | |
N7a | 0.33309 (10) | 0.22484 (16) | 0.51655 (19) | 0.0201 (5) | |
N54 | 0.11720 (12) | 0.45234 (17) | −0.2053 (2) | 0.0285 (6) | |
C2 | 0.40156 (12) | 0.28667 (19) | 0.6894 (2) | 0.0192 (5) | |
C3 | 0.38083 (12) | 0.36589 (19) | 0.6023 (2) | 0.0199 (5) | |
C3a | 0.33697 (12) | 0.32057 (19) | 0.4917 (2) | 0.0196 (5) | |
C5 | 0.25899 (12) | 0.29502 (19) | 0.2826 (2) | 0.0184 (5) | |
C6 | 0.25238 (12) | 0.19857 (19) | 0.3066 (2) | 0.0196 (5) | |
C7 | 0.29180 (12) | 0.15067 (19) | 0.4309 (2) | 0.0214 (6) | |
C21 | 0.44740 (12) | 0.28813 (19) | 0.8235 (2) | 0.0197 (5) | |
C22 | 0.48543 (12) | 0.2050 (2) | 0.8789 (2) | 0.0214 (6) | |
C23 | 0.52645 (12) | 0.2035 (2) | 1.0055 (2) | 0.0237 (6) | |
C24 | 0.52908 (12) | 0.2853 (2) | 1.0757 (2) | 0.0235 (6) | |
C25 | 0.49190 (13) | 0.3679 (2) | 1.0228 (2) | 0.0261 (6) | |
C26 | 0.45100 (12) | 0.3691 (2) | 0.8968 (2) | 0.0237 (6) | |
C31 | 0.39776 (13) | 0.4690 (2) | 0.6164 (2) | 0.0243 (6) | |
C51 | 0.22207 (12) | 0.34056 (19) | 0.1571 (2) | 0.0198 (6) | |
C52 | 0.25311 (13) | 0.3684 (2) | 0.0912 (2) | 0.0234 (6) | |
C53 | 0.21878 (13) | 0.4055 (2) | −0.0271 (2) | 0.0241 (6) | |
C54 | 0.15351 (13) | 0.41582 (19) | −0.0774 (2) | 0.0224 (6) | |
C55 | 0.12178 (13) | 0.3914 (2) | −0.0134 (2) | 0.0240 (6) | |
C56 | 0.15671 (13) | 0.3539 (2) | 0.1057 (2) | 0.0240 (6) | |
C61 | 0.20890 (12) | 0.1314 (2) | 0.2131 (2) | 0.0228 (6) | |
H4 | 0.3044 | 0.4190 | 0.3551 | 0.025* | |
H7A | 0.2637 | 0.1224 | 0.4612 | 0.026* | |
H7B | 0.3176 | 0.0960 | 0.4237 | 0.026* | |
H22 | 0.4833 | 0.1492 | 0.8298 | 0.026* | |
H23 | 0.5523 | 0.1470 | 1.0432 | 0.028* | |
H25 | 0.4943 | 0.4235 | 1.0723 | 0.031* | |
H26 | 0.4251 | 0.4259 | 0.8600 | 0.028* | |
H31 | 0.4318 | 0.4904 | 0.6930 | 0.029* | |
H52 | 0.2980 | 0.3618 | 0.1275 | 0.028* | |
H53 | 0.2396 | 0.4237 | −0.0733 | 0.029* | |
H55 | 0.0770 | 0.4000 | −0.0495 | 0.029* | |
H56 | 0.1358 | 0.3373 | 0.1521 | 0.029* | |
H61 | 0.1839 | 0.1548 | 0.1310 | 0.027* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl24 | 0.0346 (4) | 0.0341 (4) | 0.0177 (3) | −0.0021 (3) | 0.0014 (3) | 0.0000 (3) |
O31 | 0.0401 (12) | 0.0239 (11) | 0.0253 (10) | −0.0019 (9) | 0.0082 (9) | 0.0039 (9) |
O61 | 0.0333 (11) | 0.0170 (10) | 0.0243 (10) | −0.0025 (8) | 0.0092 (9) | −0.0019 (8) |
O541 | 0.0308 (12) | 0.0391 (13) | 0.0303 (11) | 0.0055 (10) | 0.0027 (9) | 0.0110 (10) |
O542 | 0.0502 (14) | 0.0460 (14) | 0.0236 (11) | −0.0016 (11) | 0.0183 (10) | 0.0070 (10) |
N1 | 0.0227 (11) | 0.0226 (12) | 0.0146 (10) | −0.0007 (9) | 0.0059 (9) | 0.0010 (9) |
N4 | 0.0262 (12) | 0.0152 (11) | 0.0157 (10) | 0.0005 (9) | 0.0055 (9) | 0.0012 (9) |
N7a | 0.0223 (11) | 0.0195 (11) | 0.0150 (10) | 0.0005 (9) | 0.0060 (9) | 0.0004 (9) |
N54 | 0.0346 (14) | 0.0234 (13) | 0.0208 (12) | −0.0015 (11) | 0.0080 (11) | 0.0032 (10) |
C2 | 0.0184 (12) | 0.0207 (13) | 0.0189 (12) | 0.0016 (10) | 0.0091 (11) | 0.0004 (11) |
C3 | 0.0203 (13) | 0.0187 (13) | 0.0166 (12) | 0.0005 (10) | 0.0056 (10) | 0.0018 (10) |
C3a | 0.0184 (13) | 0.0204 (13) | 0.0208 (13) | 0.0009 (10) | 0.0101 (11) | 0.0021 (11) |
C5 | 0.0194 (12) | 0.0191 (13) | 0.0154 (12) | −0.0008 (10) | 0.0073 (10) | −0.0029 (10) |
C6 | 0.0182 (12) | 0.0217 (14) | 0.0171 (12) | 0.0008 (11) | 0.0070 (10) | −0.0009 (10) |
C7 | 0.0245 (14) | 0.0178 (13) | 0.0194 (13) | −0.0015 (11) | 0.0084 (11) | −0.0012 (10) |
C21 | 0.0177 (12) | 0.0212 (13) | 0.0182 (12) | −0.0025 (10) | 0.0071 (10) | 0.0001 (11) |
C22 | 0.0218 (13) | 0.0215 (14) | 0.0199 (13) | −0.0015 (11) | 0.0092 (11) | −0.0001 (11) |
C23 | 0.0204 (13) | 0.0261 (15) | 0.0216 (13) | −0.0008 (11) | 0.0076 (11) | 0.0057 (11) |
C24 | 0.0208 (13) | 0.0289 (15) | 0.0166 (12) | −0.0038 (11) | 0.0055 (11) | 0.0010 (11) |
C25 | 0.0259 (14) | 0.0267 (15) | 0.0222 (14) | −0.0031 (12) | 0.0087 (12) | −0.0045 (12) |
C26 | 0.0221 (14) | 0.0224 (14) | 0.0244 (14) | 0.0000 (11) | 0.0094 (11) | 0.0021 (11) |
C31 | 0.0239 (14) | 0.0227 (14) | 0.0204 (13) | −0.0031 (11) | 0.0059 (11) | 0.0012 (11) |
C51 | 0.0245 (14) | 0.0158 (13) | 0.0170 (12) | −0.0011 (10) | 0.0081 (11) | −0.0032 (10) |
C52 | 0.0212 (13) | 0.0258 (14) | 0.0217 (13) | 0.0011 (11) | 0.0090 (11) | −0.0011 (11) |
C53 | 0.0285 (15) | 0.0255 (15) | 0.0223 (13) | 0.0007 (12) | 0.0153 (12) | 0.0006 (11) |
C54 | 0.0276 (14) | 0.0178 (13) | 0.0179 (13) | 0.0016 (11) | 0.0078 (11) | 0.0002 (10) |
C55 | 0.0221 (13) | 0.0219 (14) | 0.0224 (14) | −0.0003 (11) | 0.0061 (11) | 0.0026 (11) |
C56 | 0.0256 (14) | 0.0241 (14) | 0.0226 (13) | −0.0017 (11) | 0.0118 (12) | 0.0011 (11) |
C61 | 0.0228 (14) | 0.0216 (14) | 0.0208 (13) | 0.0017 (11) | 0.0078 (11) | −0.0012 (11) |
Cl24—C24 | 1.742 (3) | C21—C26 | 1.391 (4) |
O541—N54 | 1.224 (3) | C21—C22 | 1.396 (4) |
O542—N54 | 1.229 (3) | C22—C23 | 1.391 (4) |
N1—C2 | 1.329 (3) | C22—H22 | 0.95 |
C2—C3 | 1.423 (4) | C23—C24 | 1.382 (4) |
C3—C3a | 1.401 (4) | C23—H23 | 0.95 |
C3a—N4 | 1.377 (3) | C24—C25 | 1.376 (4) |
N4—C5 | 1.374 (3) | C25—C26 | 1.385 (4) |
C5—C6 | 1.356 (4) | C25—H25 | 0.95 |
C6—C7 | 1.507 (4) | C26—H26 | 0.95 |
C7—N7a | 1.445 (3) | C31—H31 | 0.95 |
N7a—N1 | 1.371 (3) | C51—C56 | 1.390 (4) |
C3a—N7a | 1.337 (3) | C51—C52 | 1.391 (4) |
C3—C31 | 1.432 (4) | C52—C53 | 1.381 (4) |
C31—O31 | 1.222 (3) | C52—H52 | 0.95 |
C6—C61 | 1.442 (4) | C53—C54 | 1.385 (4) |
C61—O61 | 1.223 (3) | C53—H53 | 0.95 |
N4—H4 | 0.88 | C54—C55 | 1.372 (4) |
N54—C54 | 1.474 (3) | C55—C56 | 1.392 (4) |
C2—C21 | 1.484 (3) | C55—H55 | 0.95 |
C5—C51 | 1.497 (3) | C56—H56 | 0.95 |
C7—H7A | 0.99 | C61—H61 | 0.95 |
C7—H7B | 0.99 | ||
C2—N1—N7a | 104.8 (2) | C24—C23—C22 | 119.2 (2) |
C5—N4—C3a | 119.5 (2) | C24—C23—H23 | 120.4 |
C5—N4—H4 | 118.9 | C22—C23—H23 | 120.4 |
C3a—N4—H4 | 121.6 | C25—C24—C23 | 121.3 (2) |
C3a—N7a—N1 | 112.4 (2) | C25—C24—Cl24 | 118.4 (2) |
C3a—N7a—C7 | 126.5 (2) | C23—C24—Cl24 | 120.3 (2) |
N1—N7a—C7 | 121.0 (2) | C24—C25—C26 | 119.4 (3) |
O541—N54—O542 | 124.0 (2) | C24—C25—H25 | 120.3 |
O541—N54—C54 | 118.1 (2) | C26—C25—H25 | 120.3 |
O542—N54—C54 | 117.9 (2) | C25—C26—C21 | 120.7 (3) |
N1—C2—C3 | 111.7 (2) | C25—C26—H26 | 119.7 |
N1—C2—C21 | 118.8 (2) | C21—C26—H26 | 119.7 |
C3—C2—C21 | 129.5 (2) | O31—C31—C3 | 123.7 (2) |
C3a—C3—C2 | 103.8 (2) | O31—C31—H31 | 118.2 |
C3a—C3—C31 | 125.2 (2) | C3—C31—H31 | 118.2 |
C2—C3—C31 | 131.1 (2) | C56—C51—C52 | 119.9 (2) |
N7a—C3a—N4 | 120.4 (2) | C56—C51—C5 | 120.2 (2) |
N7a—C3a—C3 | 107.3 (2) | C52—C51—C5 | 119.9 (2) |
N4—C3a—C3 | 132.2 (2) | C53—C52—C51 | 120.1 (2) |
C6—C5—N4 | 121.1 (2) | C53—C52—H52 | 120.0 |
C6—C5—C51 | 123.0 (2) | C51—C52—H52 | 120.0 |
N4—C5—C51 | 116.0 (2) | C52—C53—C54 | 118.9 (3) |
C5—C6—C61 | 122.6 (2) | C52—C53—H53 | 120.6 |
C5—C6—C7 | 123.3 (2) | C54—C53—H53 | 120.6 |
C61—C6—C7 | 114.0 (2) | C55—C54—C53 | 122.4 (2) |
N7a—C7—C6 | 109.0 (2) | C55—C54—N54 | 119.3 (2) |
N7a—C7—H7A | 109.9 | C53—C54—N54 | 118.3 (2) |
C6—C7—H7A | 109.9 | C54—C55—C56 | 118.4 (3) |
N7a—C7—H7B | 109.9 | C54—C55—H55 | 120.8 |
C6—C7—H7B | 109.9 | C56—C55—H55 | 120.8 |
H7A—C7—H7B | 108.3 | C51—C56—C55 | 120.3 (3) |
C26—C21—C22 | 119.0 (2) | C51—C56—H56 | 119.8 |
C26—C21—C2 | 121.1 (2) | C55—C56—H56 | 119.8 |
C22—C21—C2 | 119.7 (2) | O61—C61—C6 | 121.3 (2) |
C23—C22—C21 | 120.4 (2) | O61—C61—H61 | 119.3 |
C23—C22—H22 | 119.8 | C6—C61—H61 | 119.3 |
C21—C22—H22 | 119.8 | ||
C2—N1—N7a—C3a | 0.0 (3) | C26—C21—C22—C23 | −0.2 (4) |
C2—N1—N7a—C7 | −178.3 (2) | C2—C21—C22—C23 | −176.9 (2) |
N7a—N1—C2—C3 | 0.7 (3) | C21—C22—C23—C24 | 0.0 (4) |
N7a—N1—C2—C21 | 178.8 (2) | C22—C23—C24—C25 | 0.1 (4) |
N1—C2—C3—C3a | −1.1 (3) | C22—C23—C24—Cl24 | 178.6 (2) |
C21—C2—C3—C3a | −179.0 (2) | C23—C24—C25—C26 | 0.0 (4) |
N1—C2—C3—C31 | 178.5 (3) | Cl24—C24—C25—C26 | −178.5 (2) |
C21—C2—C3—C31 | 0.6 (5) | C24—C25—C26—C21 | −0.2 (4) |
N1—N7a—C3a—N4 | 179.5 (2) | C22—C21—C26—C25 | 0.3 (4) |
C7—N7a—C3a—N4 | −2.4 (4) | C2—C21—C26—C25 | 177.0 (2) |
N1—N7a—C3a—C3 | −0.7 (3) | C3a—C3—C31—O31 | 7.6 (5) |
C7—N7a—C3a—C3 | 177.5 (2) | C2—C3—C31—O31 | −171.9 (3) |
C5—N4—C3a—N7a | 2.8 (4) | C5—C6—C61—O61 | −179.5 (3) |
C5—N4—C3a—C3 | −177.0 (3) | C6—C5—C51—C56 | 67.8 (4) |
C2—C3—C3a—N7a | 1.0 (3) | N4—C5—C51—C56 | −112.6 (3) |
C31—C3—C3a—N7a | −178.6 (3) | C6—C5—C51—C52 | −111.4 (3) |
C2—C3—C3a—N4 | −179.1 (3) | N4—C5—C51—C52 | 68.2 (3) |
C31—C3—C3a—N4 | 1.3 (5) | C56—C51—C52—C53 | −2.6 (4) |
C3a—N4—C5—C6 | −0.2 (4) | C5—C51—C52—C53 | 176.6 (2) |
C3a—N4—C5—C51 | −179.8 (2) | C51—C52—C53—C54 | 1.0 (4) |
N4—C5—C6—C61 | −179.8 (2) | C52—C53—C54—C55 | 0.7 (4) |
C51—C5—C6—C61 | −0.2 (4) | C52—C53—C54—N54 | −178.0 (2) |
N4—C5—C6—C7 | −3.0 (4) | O541—N54—C54—C55 | 8.9 (4) |
C51—C5—C6—C7 | 176.6 (2) | O542—N54—C54—C55 | −169.6 (2) |
C3a—N7a—C7—C6 | −0.5 (4) | C53—C54—N54—O541 | −172.4 (2) |
N1—N7a—C7—C6 | 177.5 (2) | O542—N54—C54—C53 | 9.1 (4) |
C5—C6—C7—N7a | 3.2 (4) | C53—C54—C55—C56 | −0.8 (4) |
C61—C6—C7—N7a | −179.8 (2) | N54—C54—C55—C56 | 177.8 (2) |
N1—C2—C21—C26 | −141.7 (3) | C52—C51—C56—C55 | 2.5 (4) |
C3—C2—C21—C26 | 36.1 (4) | C5—C51—C56—C55 | −176.7 (2) |
N1—C2—C21—C22 | 35.0 (4) | C54—C55—C56—C51 | −0.8 (4) |
C3—C2—C21—C22 | −147.2 (3) | C7—C6—C61—O61 | 3.4 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H4···O31 | 0.88 | 2.52 | 3.011 (3) | 116 |
N4—H4···O61i | 0.88 | 2.00 | 2.853 (3) | 163 |
C61—H61···O31ii | 0.95 | 2.47 | 3.043 (3) | 118 |
Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C20H13ClN4O4 |
Mr | 408.79 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 120 |
a, b, c (Å) | 23.943 (5), 13.445 (2), 12.336 (5) |
β (°) | 118.594 (10) |
V (Å3) | 3486.7 (17) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.26 |
Crystal size (mm) | 0.46 × 0.36 × 0.24 |
Data collection | |
Diffractometer | Bruker Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.891, 0.941 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 40202, 4002, 2520 |
Rint | 0.066 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.051, 0.139, 1.09 |
No. of reflections | 4002 |
No. of parameters | 262 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.36, −0.43 |
Computer programs: COLLECT (Nonius, 1999), DIRAX/LSQ (Duisenberg et al., 2000), EVALCCD (Duisenberg et al., 2003), SIR2004 (Burla et al., 2005), OSCAIL (McArdle, 2003) and SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003), SHELXL97 (Sheldrick, 2008) and PRPKAPPA (Ferguson, 1999).
N1—C2 | 1.329 (3) | C7—N7a | 1.445 (3) |
C2—C3 | 1.423 (4) | N7a—N1 | 1.371 (3) |
C3—C3a | 1.401 (4) | C3a—N7a | 1.337 (3) |
C3a—N4 | 1.377 (3) | C3—C31 | 1.432 (4) |
N4—C5 | 1.374 (3) | C31—O31 | 1.222 (3) |
C5—C6 | 1.356 (4) | C6—C61 | 1.442 (4) |
C6—C7 | 1.507 (4) | C61—O61 | 1.223 (3) |
N1—C2—C21—C22 | 35.0 (4) | N4—C5—C51—C52 | 68.2 (3) |
C2—C3—C31—O31 | −171.9 (3) | C53—C54—N54—O541 | −172.4 (2) |
C5—C6—C61—O61 | −179.5 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H4···O31 | 0.88 | 2.52 | 3.011 (3) | 116 |
N4—H4···O61i | 0.88 | 2.00 | 2.853 (3) | 163 |
C61—H61···O31ii | 0.95 | 2.47 | 3.043 (3) | 118 |
Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, −z+1/2. |
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As part of a continuing search for biologically active molecules containing fused pyrazole systems, we have now (Quiroga et al., 2008) prepared the title compound, (I), by use of the Vilsmeier–Haack reaction to effect double formylation of the precursor (A) (see the first scheme), itself formed by condensation of the simple reagents (B) and (C). Product (I) is of potential value as a precursor for modified or fused polycyclic pyrazolo[1,5-a]pyrimidine systems. We report here the structure of (I) and compare it with the closely related analogue, (II) (Low et al., 2006). Both the molecular structure of (I) (Fig. 1) and its supramolecular aggregation show significant differences from those of compound (II), whose constitution differs from that of (I) not only in the nature of the 4-substituents in the aryl rings pendent from positions 2 and 5, but also in the presence of an additional unsubstituted phenyl ring at position 7.
Within the molecule of (I), the six-membered heterocyclic ring is effectively planar: the maximum deviation from the mean plane through the six ring atoms is 0.021 (3) Å for atom C6. This contrasts with the corresponding ring in compound (II), which is significantly puckered into a non-planar conformation intermediate between boat and screw-boat forms (Low et al., 2006). The overall conformation of the molecule of (I) can thus be defined in terms of five torsion angles (Table 1) which show that, apart from the nitro group which makes a dihedral angle of 9.4 (2)° with the adjacent aryl ring, the conformation of (I) is broadly similar to that of (II). In particular, the two independent carboxaldehyde groups in (I) are both nearly coplanar with the heterocyclic ring system, with deviations from the mean ring plane of 0.236 (3) Å for atom O31 and 0.106 (2) Å for atom O61. While the short intramolecular N—H···O hydrogen bond to atom O31 (Table 2) may influence the orientation of one carboxaldehyde group, there is no corresponding interaction which could influence the orientation of the carboxaldehyde group bonded to atom C6. However, the intramolecular dimensions of (I) (Table 1) provide some evidence for the polarization of its molecular structure, such that the potential for electronic delocalization is optimized when the carboxaldehyde groups are coplanar with the heterocyclic system, and this may thus be the dominant factor controlling the orientation of the carboxaldehyde groups. Firstly, the C31—O31 and C61—O61 bonds are both long for their type [mean value 1.192 Å (Allen et al., 1987)], while the C3—C31 and C6—C61 bonds are both short (mean value 1.464 Å). Secondly, the C5—C6 bond is long for its type (mean value 1.331 Å), and the C3a—N4 and N4—C5 bonds have almost identical lengths. These observations, taken all together, indicate that polarized forms such as (Ia)–(Ic) (see the second scheme) are contributors to the overall molecular-electronic structure. The molecular dimensions of compound (II) were not discussed in the original report (Low et al., 2006), but re-examination of the structure of (II) shows that it exhibits exactly the same pattern of intramolecular distances as found here for (I), pointing to a similar interpretation of the carboxaldehyde conformations.
The intramolecular hydrogen bond mentioned earlier forms an S(6) motif (Bernstein et al., 1995) and it is, in fact, the longer and weaker component of an asymmetric three-centre N—H···(O)2 system (Table 2), in which the shorter component links the molecules at (x, y, z) and (1/2 - x, 1/2 + y, 1/2 - z), which are related by the 21 screw axis along (1/4, y, 1/4). Propagation of this hydrogen bond forms a C(6) chain running parallel to the [010] direction (Fig. 2). This [010] chain is reinforced by a C—H···O hydrogen bond which forms a C(9) chain, and the combination of all these hydrogen bonds generates an S(6)C(6)C(9)[R22(5)] chain of rings (Fig. 2). In this chain, the R22(5) motif actually contains three hydrogen bonds, but atoms H4 and O31 act, respectively, as a double donor and a double acceptor. Four chains of this type pass through each unit cell, but there are no direction-specific interactions between the chains.
It is interesting to note that, despite the large excess in (I) of potential hydrogen-bond donors in the form of aromatic C—H bonds over potential hydrogen-bond acceptors, the O atoms of the nitro group play no part in the hydrogen bonding. Nor are there any dipolar nitro···nitro interactions (Garden et al., 2006; Glidewell et al., 2006), analogous to the well documented dipolar carbonyl···carbonyl interactions (Allen et al., 1998).
The action of the hydrogen bonds in (I) differs from that in (II) (Low et al., 2006). While (II) also contains an asymmetric N—H···(O)2 system, the shorter component generates a centrosymmetric dimer containing an R22(12) motif, rather than a C(6) chain as in (I). There are two C—H···O hydrogen bonds in the structure of (II), which link the R22(12) dimers into sheets, but both of these donor atoms are components of the unsubstituted phenyl ring, which is absent from the constitution of (I). Hence, the supramolecular aggregation in compounds of this type is very markedly influenced by the nature of the peripheral substituents.