Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680100366X/na6054sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S160053680100366X/na6054Isup2.hkl |
CCDC reference: 159879
Equimolar quantities of ethyl malonate and pyridine, each 0.5 g (6.3 mmol), and 9-aldehyde acridine (1 g, 0.5 mmol) in 30 ml diethyl ether were added to a 100 ml three-necked flask fitted with a reflux condenser. The mixture was stirred at room temperature. Then, 3 ml titanium tetrachloride (TiCl4) dissolved in 20 ml diethyl ether were added. At the end of the addition reaction, the mixture was stirred and refluxed for 8 h. The solution was filtered and extracted with diethyl ether (50 ml). The solvent was removed using a rotary evaporator. The residue was recrystallized from ethyl ether and hexane (2:3 ratio) leading to yellow crystals of the title compound.
All H atoms were located by difference Fourier synthesis and were refined with fixed individual displacement parameters [U(H) = 1.2Ueq(C) or 1.5Ueq(Cmethyl)] using a riding model with aromatic C—H = 0.95 Å, methyl C—H = 0.98 Å or methylene C—H = 0.99 Å.
Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).
Fig. 1. A perspective view of (II) with the atom-numbering scheme. Displacement ellipsoids are at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii. |
C21H19NO4 | F(000) = 736 |
Mr = 349.37 | Dx = 1.333 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 9.8535 (7) Å | Cell parameters from 509 reflections |
b = 14.888 (1) Å | θ = 1–20° |
c = 12.5317 (8) Å | µ = 0.09 mm−1 |
β = 108.805 (5)° | T = 173 K |
V = 1740.3 (2) Å3 | Block, yellow |
Z = 4 | 0.68 × 0.62 × 0.28 mm |
Siemens CCD three-circle diffractometer | 3553 independent reflections |
Radiation source: fine-focus sealed tube | 3240 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
ω scans | θmax = 27.1°, θmin = 2.2° |
Absorption correction: empirical (SADABS; Sheldrick, 1996) | h = −12→12 |
Tmin = 0.940, Tmax = 0.975 | k = −17→18 |
25802 measured reflections | l = −15→15 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.036 | H-atom parameters constrained |
wR(F2) = 0.086 | w = 1/[σ2(Fo2) + (0.0336P)2 + 0.6851P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
3553 reflections | Δρmax = 0.21 e Å−3 |
236 parameters | Δρmin = −0.17 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0117 (11) |
C21H19NO4 | V = 1740.3 (2) Å3 |
Mr = 349.37 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.8535 (7) Å | µ = 0.09 mm−1 |
b = 14.888 (1) Å | T = 173 K |
c = 12.5317 (8) Å | 0.68 × 0.62 × 0.28 mm |
β = 108.805 (5)° |
Siemens CCD three-circle diffractometer | 3553 independent reflections |
Absorption correction: empirical (SADABS; Sheldrick, 1996) | 3240 reflections with I > 2σ(I) |
Tmin = 0.940, Tmax = 0.975 | Rint = 0.025 |
25802 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.086 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.21 e Å−3 |
3553 reflections | Δρmin = −0.17 e Å−3 |
236 parameters |
Experimental. ; |
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 | 0.26955 (12) | 0.42640 (8) | 0.16720 (9) | 0.0231 (2) | |
C2 | 0.20494 (11) | 0.42147 (8) | 0.25206 (9) | 0.0227 (2) | |
C3 | 0.23026 (12) | 0.35032 (8) | 0.33269 (10) | 0.0262 (3) | |
H3 | 0.2963 | 0.3040 | 0.3319 | 0.031* | |
C4 | 0.16102 (13) | 0.34806 (8) | 0.41057 (10) | 0.0288 (3) | |
H4 | 0.1801 | 0.3007 | 0.4642 | 0.035* | |
C5 | 0.06042 (13) | 0.41579 (9) | 0.41266 (10) | 0.0311 (3) | |
H5 | 0.0122 | 0.4131 | 0.4671 | 0.037* | |
C6 | 0.03282 (13) | 0.48421 (8) | 0.33754 (10) | 0.0289 (3) | |
H6 | −0.0346 | 0.5291 | 0.3401 | 0.035* | |
C7 | 0.10332 (12) | 0.49015 (8) | 0.25457 (9) | 0.0237 (2) | |
N8 | 0.06857 (10) | 0.55913 (7) | 0.18145 (8) | 0.0259 (2) | |
C9 | 0.13105 (12) | 0.56268 (8) | 0.10047 (10) | 0.0247 (2) | |
C10 | 0.09174 (13) | 0.63450 (8) | 0.02092 (10) | 0.0300 (3) | |
H10 | 0.0262 | 0.6790 | 0.0281 | 0.036* | |
C11 | 0.14732 (14) | 0.63971 (9) | −0.06492 (11) | 0.0336 (3) | |
H11 | 0.1188 | 0.6873 | −0.1179 | 0.040* | |
C12 | 0.24739 (14) | 0.57509 (9) | −0.07665 (11) | 0.0328 (3) | |
H12 | 0.2851 | 0.5797 | −0.1373 | 0.039* | |
C13 | 0.28964 (13) | 0.50660 (8) | −0.00138 (10) | 0.0283 (3) | |
H13 | 0.3582 | 0.4644 | −0.0091 | 0.034* | |
C14 | 0.23219 (12) | 0.49736 (8) | 0.08916 (9) | 0.0236 (2) | |
C15 | 0.36460 (12) | 0.35354 (8) | 0.15277 (10) | 0.0247 (2) | |
H15 | 0.3288 | 0.3176 | 0.0870 | 0.030* | |
C16 | 0.49443 (12) | 0.33298 (8) | 0.22174 (9) | 0.0240 (2) | |
C17 | 0.56797 (12) | 0.25193 (8) | 0.19547 (10) | 0.0245 (2) | |
O17 | 0.51567 (9) | 0.20410 (6) | 0.11525 (7) | 0.0332 (2) | |
O18 | 0.69742 (9) | 0.24075 (6) | 0.27090 (7) | 0.0299 (2) | |
C19 | 0.77218 (13) | 0.15790 (8) | 0.26135 (11) | 0.0310 (3) | |
H19A | 0.7666 | 0.1477 | 0.1820 | 0.037* | |
H19B | 0.7279 | 0.1060 | 0.2869 | 0.037* | |
C20 | 0.92543 (13) | 0.16831 (9) | 0.33415 (11) | 0.0344 (3) | |
H20A | 0.9788 | 0.1136 | 0.3298 | 0.052* | |
H20B | 0.9295 | 0.1784 | 0.4124 | 0.052* | |
H20C | 0.9681 | 0.2197 | 0.3079 | 0.052* | |
C21 | 0.57236 (12) | 0.38889 (8) | 0.32314 (10) | 0.0257 (3) | |
O21 | 0.62386 (12) | 0.46068 (6) | 0.31636 (8) | 0.0445 (3) | |
O22 | 0.57564 (9) | 0.34863 (6) | 0.41841 (7) | 0.0311 (2) | |
C23 | 0.65208 (15) | 0.39471 (10) | 0.52345 (10) | 0.0360 (3) | |
H23A | 0.6350 | 0.4603 | 0.5150 | 0.043* | |
H23B | 0.7564 | 0.3837 | 0.5439 | 0.043* | |
C24 | 0.59637 (16) | 0.35829 (11) | 0.61253 (11) | 0.0419 (3) | |
H24A | 0.6457 | 0.3877 | 0.6846 | 0.063* | |
H24B | 0.6137 | 0.2934 | 0.6199 | 0.063* | |
H24C | 0.4932 | 0.3699 | 0.5914 | 0.063* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0203 (5) | 0.0239 (6) | 0.0229 (6) | −0.0018 (4) | 0.0040 (4) | −0.0029 (4) |
C2 | 0.0208 (5) | 0.0231 (6) | 0.0221 (5) | −0.0014 (4) | 0.0040 (4) | −0.0023 (4) |
C3 | 0.0250 (6) | 0.0246 (6) | 0.0278 (6) | 0.0014 (4) | 0.0069 (5) | 0.0007 (5) |
C4 | 0.0322 (6) | 0.0273 (6) | 0.0268 (6) | −0.0002 (5) | 0.0091 (5) | 0.0038 (5) |
C5 | 0.0339 (7) | 0.0346 (7) | 0.0284 (6) | 0.0003 (5) | 0.0150 (5) | −0.0005 (5) |
C6 | 0.0287 (6) | 0.0300 (6) | 0.0297 (6) | 0.0042 (5) | 0.0119 (5) | −0.0016 (5) |
C7 | 0.0228 (5) | 0.0238 (6) | 0.0226 (6) | −0.0011 (4) | 0.0045 (4) | −0.0023 (4) |
N8 | 0.0267 (5) | 0.0245 (5) | 0.0252 (5) | 0.0016 (4) | 0.0064 (4) | −0.0005 (4) |
C9 | 0.0244 (6) | 0.0237 (6) | 0.0227 (6) | −0.0037 (4) | 0.0030 (4) | −0.0021 (4) |
C10 | 0.0317 (6) | 0.0254 (6) | 0.0290 (6) | −0.0005 (5) | 0.0045 (5) | 0.0016 (5) |
C11 | 0.0394 (7) | 0.0289 (6) | 0.0281 (6) | −0.0052 (5) | 0.0048 (5) | 0.0058 (5) |
C12 | 0.0363 (7) | 0.0365 (7) | 0.0261 (6) | −0.0097 (5) | 0.0105 (5) | 0.0001 (5) |
C13 | 0.0277 (6) | 0.0308 (6) | 0.0265 (6) | −0.0046 (5) | 0.0090 (5) | −0.0033 (5) |
C14 | 0.0218 (5) | 0.0250 (6) | 0.0215 (5) | −0.0044 (4) | 0.0036 (4) | −0.0029 (4) |
C15 | 0.0285 (6) | 0.0250 (6) | 0.0224 (6) | −0.0011 (5) | 0.0106 (5) | −0.0018 (4) |
C16 | 0.0262 (6) | 0.0244 (6) | 0.0232 (6) | −0.0006 (4) | 0.0104 (5) | −0.0002 (4) |
C17 | 0.0271 (6) | 0.0246 (6) | 0.0233 (6) | −0.0004 (5) | 0.0099 (5) | 0.0013 (5) |
O17 | 0.0347 (5) | 0.0327 (5) | 0.0289 (5) | 0.0055 (4) | 0.0055 (4) | −0.0071 (4) |
O18 | 0.0268 (4) | 0.0281 (4) | 0.0318 (5) | 0.0050 (3) | 0.0053 (4) | −0.0053 (4) |
C19 | 0.0298 (6) | 0.0256 (6) | 0.0352 (7) | 0.0065 (5) | 0.0068 (5) | −0.0019 (5) |
C20 | 0.0292 (6) | 0.0356 (7) | 0.0365 (7) | 0.0048 (5) | 0.0081 (5) | 0.0012 (6) |
C21 | 0.0242 (6) | 0.0253 (6) | 0.0282 (6) | 0.0016 (5) | 0.0094 (5) | −0.0009 (5) |
O21 | 0.0618 (7) | 0.0319 (5) | 0.0375 (5) | −0.0160 (5) | 0.0127 (5) | −0.0019 (4) |
O22 | 0.0362 (5) | 0.0322 (5) | 0.0235 (4) | −0.0088 (4) | 0.0077 (4) | −0.0044 (3) |
C23 | 0.0374 (7) | 0.0413 (7) | 0.0264 (6) | −0.0113 (6) | 0.0065 (5) | −0.0091 (5) |
C24 | 0.0467 (8) | 0.0505 (9) | 0.0270 (7) | −0.0118 (7) | 0.0098 (6) | −0.0072 (6) |
C1—C14 | 1.4057 (16) | C13—H13 | 0.9500 |
C1—C2 | 1.4064 (16) | C15—C16 | 1.3284 (16) |
C1—C15 | 1.4819 (16) | C15—H15 | 0.9500 |
C2—C3 | 1.4292 (16) | C16—C17 | 1.4978 (16) |
C2—C7 | 1.4386 (16) | C16—C21 | 1.5060 (16) |
C3—C4 | 1.3596 (17) | C17—O17 | 1.2038 (14) |
C3—H3 | 0.9500 | C17—O18 | 1.3308 (14) |
C4—C5 | 1.4202 (17) | O18—C19 | 1.4613 (14) |
C4—H4 | 0.9500 | C19—C20 | 1.4995 (17) |
C5—C6 | 1.3538 (18) | C19—H19A | 0.9900 |
C5—H5 | 0.9500 | C19—H19B | 0.9900 |
C6—C7 | 1.4272 (16) | C20—H20A | 0.9800 |
C6—H6 | 0.9500 | C20—H20B | 0.9800 |
C7—N8 | 1.3451 (15) | C20—H20C | 0.9800 |
N8—C9 | 1.3471 (15) | C21—O21 | 1.1978 (15) |
C9—C10 | 1.4277 (16) | C21—O22 | 1.3270 (14) |
C9—C14 | 1.4317 (16) | O22—C23 | 1.4600 (14) |
C10—C11 | 1.3576 (18) | C23—C24 | 1.4956 (19) |
C10—H10 | 0.9500 | C23—H23A | 0.9900 |
C11—C12 | 1.4188 (19) | C23—H23B | 0.9900 |
C11—H11 | 0.9500 | C24—H24A | 0.9800 |
C12—C13 | 1.3601 (18) | C24—H24B | 0.9800 |
C12—H12 | 0.9500 | C24—H24C | 0.9800 |
C13—C14 | 1.4286 (16) | ||
C14—C1—C2 | 118.98 (10) | C13—C14—C9 | 118.68 (10) |
C14—C1—C15 | 119.96 (10) | C16—C15—C1 | 127.10 (11) |
C2—C1—C15 | 120.80 (10) | C16—C15—H15 | 116.4 |
C1—C2—C3 | 123.70 (10) | C1—C15—H15 | 116.4 |
C1—C2—C7 | 117.86 (10) | C15—C16—C17 | 118.38 (10) |
C3—C2—C7 | 118.39 (10) | C15—C16—C21 | 122.94 (10) |
C4—C3—C2 | 120.81 (11) | C17—C16—C21 | 118.66 (10) |
C4—C3—H3 | 119.6 | O17—C17—O18 | 125.00 (11) |
C2—C3—H3 | 119.6 | O17—C17—C16 | 123.57 (11) |
C3—C4—C5 | 120.69 (11) | O18—C17—C16 | 111.43 (10) |
C3—C4—H4 | 119.7 | C17—O18—C19 | 116.13 (9) |
C5—C4—H4 | 119.7 | O18—C19—C20 | 107.35 (10) |
C6—C5—C4 | 120.43 (11) | O18—C19—H19A | 110.2 |
C6—C5—H5 | 119.8 | C20—C19—H19A | 110.2 |
C4—C5—H5 | 119.8 | O18—C19—H19B | 110.2 |
C5—C6—C7 | 121.15 (11) | C20—C19—H19B | 110.2 |
C5—C6—H6 | 119.4 | H19A—C19—H19B | 108.5 |
C7—C6—H6 | 119.4 | C19—C20—H20A | 109.5 |
N8—C7—C6 | 117.82 (10) | C19—C20—H20B | 109.5 |
N8—C7—C2 | 123.63 (10) | H20A—C20—H20B | 109.5 |
C6—C7—C2 | 118.53 (10) | C19—C20—H20C | 109.5 |
C7—N8—C9 | 117.74 (10) | H20A—C20—H20C | 109.5 |
N8—C9—C10 | 117.94 (11) | H20B—C20—H20C | 109.5 |
N8—C9—C14 | 123.34 (10) | O21—C21—O22 | 125.37 (11) |
C10—C9—C14 | 118.71 (11) | O21—C21—C16 | 123.08 (11) |
C11—C10—C9 | 120.54 (12) | O22—C21—C16 | 111.55 (10) |
C11—C10—H10 | 119.7 | C21—O22—C23 | 117.05 (10) |
C9—C10—H10 | 119.7 | O22—C23—C24 | 107.21 (10) |
C10—C11—C12 | 120.98 (12) | O22—C23—H23A | 110.3 |
C10—C11—H11 | 119.5 | C24—C23—H23A | 110.3 |
C12—C11—H11 | 119.5 | O22—C23—H23B | 110.3 |
C13—C12—C11 | 120.27 (12) | C24—C23—H23B | 110.3 |
C13—C12—H12 | 119.9 | H23A—C23—H23B | 108.5 |
C11—C12—H12 | 119.9 | C23—C24—H24A | 109.5 |
C12—C13—C14 | 120.79 (12) | C23—C24—H24B | 109.5 |
C12—C13—H13 | 119.6 | H24A—C24—H24B | 109.5 |
C14—C13—H13 | 119.6 | C23—C24—H24C | 109.5 |
C1—C14—C13 | 122.88 (11) | H24A—C24—H24C | 109.5 |
C1—C14—C9 | 118.43 (10) | H24B—C24—H24C | 109.5 |
C14—C1—C2—C3 | 177.23 (10) | C2—C1—C14—C9 | 0.92 (16) |
C15—C1—C2—C3 | 3.19 (17) | C15—C1—C14—C9 | 175.01 (10) |
C14—C1—C2—C7 | −0.14 (15) | C12—C13—C14—C1 | 178.23 (11) |
C15—C1—C2—C7 | −174.18 (10) | C12—C13—C14—C9 | −1.16 (17) |
C1—C2—C3—C4 | −177.98 (11) | N8—C9—C14—C1 | −0.73 (16) |
C7—C2—C3—C4 | −0.62 (17) | C10—C9—C14—C1 | −179.48 (10) |
C2—C3—C4—C5 | 0.83 (18) | N8—C9—C14—C13 | 178.68 (10) |
C3—C4—C5—C6 | −0.57 (19) | C10—C9—C14—C13 | −0.07 (16) |
C4—C5—C6—C7 | 0.10 (19) | C14—C1—C15—C16 | 116.28 (13) |
C5—C6—C7—N8 | 178.82 (11) | C2—C1—C15—C16 | −69.74 (16) |
C5—C6—C7—C2 | 0.09 (17) | C1—C15—C16—C17 | 175.44 (10) |
C1—C2—C7—N8 | −0.98 (16) | C1—C15—C16—C21 | −6.31 (18) |
C3—C2—C7—N8 | −178.50 (11) | C15—C16—C17—O17 | −0.21 (17) |
C1—C2—C7—C6 | 177.68 (10) | C21—C16—C17—O17 | −178.55 (11) |
C3—C2—C7—C6 | 0.16 (16) | C15—C16—C17—O18 | 179.12 (10) |
C6—C7—N8—C9 | −177.46 (10) | C21—C16—C17—O18 | 0.79 (14) |
C2—C7—N8—C9 | 1.20 (16) | O17—C17—O18—C19 | −7.67 (17) |
C7—N8—C9—C10 | 178.43 (10) | C16—C17—O18—C19 | 173.01 (9) |
C7—N8—C9—C14 | −0.33 (16) | C17—O18—C19—C20 | 166.89 (10) |
N8—C9—C10—C11 | −177.63 (11) | C15—C16—C21—O21 | −72.84 (17) |
C14—C9—C10—C11 | 1.19 (17) | C17—C16—C21—O21 | 105.41 (14) |
C9—C10—C11—C12 | −1.11 (18) | C15—C16—C21—O22 | 107.05 (13) |
C10—C11—C12—C13 | −0.14 (19) | C17—C16—C21—O22 | −74.69 (13) |
C11—C12—C13—C14 | 1.28 (18) | O21—C21—O22—C23 | −1.91 (18) |
C2—C1—C14—C13 | −178.46 (10) | C16—C21—O22—C23 | 178.21 (10) |
C15—C1—C14—C13 | −4.37 (17) | C21—O22—C23—C24 | 158.67 (11) |
Experimental details
Crystal data | |
Chemical formula | C21H19NO4 |
Mr | 349.37 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 173 |
a, b, c (Å) | 9.8535 (7), 14.888 (1), 12.5317 (8) |
β (°) | 108.805 (5) |
V (Å3) | 1740.3 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.68 × 0.62 × 0.28 |
Data collection | |
Diffractometer | Siemens CCD three-circle diffractometer |
Absorption correction | Empirical (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.940, 0.975 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 25802, 3553, 3240 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.641 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.086, 1.05 |
No. of reflections | 3553 |
No. of parameters | 236 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.21, −0.17 |
Computer programs: SMART (Siemens, 1995), SMART, SAINT (Siemens, 1995), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), XP in SHELXTL-Plus (Sheldrick, 1991).
C7—N8 | 1.3451 (15) | N8—C9 | 1.3471 (15) |
C7—N8—C9 | 117.74 (10) | ||
C1—C15—C16—C17 | 175.44 (10) | C17—O18—C19—C20 | 166.89 (10) |
C1—C15—C16—C21 | −6.31 (18) | C15—C16—C21—O21 | −72.84 (17) |
C15—C16—C17—O17 | −0.21 (17) | C15—C16—C21—O22 | 107.05 (13) |
C15—C16—C17—O18 | 179.12 (10) | C16—C21—O22—C23 | 178.21 (10) |
C16—C17—O18—C19 | 173.01 (9) | C21—O22—C23—C24 | 158.67 (11) |
Derivatives of acridine are very important building blocks in synthetic chemistry. They have interesting biological and photophysical properties (Galy et al., 1980). We have recently described the preparation of diethyl 2-anthracen-9-ylmethylenemalonate (Elazami et al., 1999). Such compounds are prepared by the condensation reaction of 9-aldehyde acridine (I) and ethyl malonate (see scheme below). We present here the structure of diethyl 2-acridin-9-ylmethylenemalonate, (II), which was synthesized according to the method of Lehnert (1972). (II) displays a high stability at room temperature and its structure has been determined by IR, mass, UV and NMR (1H, 13C) spectroscopy. Since NMR and mass spectroscopy did not provide sufficient information about the conformation of the reaction product, we have carried out the X-ray structure analysis.
The title compound contains an acridine ring system to which an ethylene bond is attached at position 9. Due to steric hindrance this ethylene bond cannot be coplanar with the aromatic ring system: the angle between the acridine ring system and the ethylene moiety is 68.30 (2)°. Whereas one of the ester groups (O17, C17, O18, C19, C20) is nearly planar (r.m.s.d. = 0.232 Å) and coplanar with the ethylene bond (Table 1), the other one (C21, O21, O22, C23, C24) is less planar (r.m.s.d. = 0.318 Å) and it is tilted by 77.34 (5)° out of the plane of the ethylene bond. The aromatic ring systems of two adjacent molecules are partly stacked with an interplanar distance of approximately 3.5 Å.
It is remarkable that compound (II) is isostructural with diethyl 2-anthracen-9-ylmethylenemalonate (Elazami et al., 1999). A least-squares fit of all non-H atoms gives an r.m.s. deviation of 0.082 Å. There are no significant differences between both structures apart from the geometry around the N atom: the C—N bonds (Table 2) are of course shorter than the respective C—C bonds [1.395 (3) and 1.397 (3) Å] and the C—N—C angle is smaller than the corresponding C—C—C angle [122.4 (2)°].