Diethyl 4-(2,5-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, C21H27NO6, (I), diethyl 4-(3,4-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate, C21H27NO6, (II), and diethyl 2,6-dimethyl-4-(3,4,5-trimethoxyphenyl)-1,4-dihydropyridine-3,5-dicarboxylate, C22H29NO7, (III), crystallize with hydrogen-bonding networks involving the H atom bonded to the N atom of the 1,4-dihydropyridine ring and carbonyl O atoms in (I) and (II). Unusually, (III) shows O atoms of methoxy groups serving as hydrogen-bond acceptors.
Supporting information
CCDC references: 152607; 152608; 152609
For (I), an ethanol solution (40 ml) of 2,5-dimethoxybenzaldehyde (6.4 g, 0.0386 mol), ethyl acetoacetate (10.036 g, 0.0772 mol), and ammonium hydroxide (2.027 g, 9,9579 mol) was refluxed for 6 h. Acetonitrile was added to the resulting immiscible liquids, following which all solvent was removed under reduced pressure. The remaining solid was recrystallized from methanol giving large yellow cubes.
For (II), an ethanol solution of 3,4-dimethoxybenzaldehyde (6.4 g, 0.0386 mol), ethylacetoacetate (10.036 g, 0.0772 mol) and ammonium hydroxide (2.027 g, 0.0579 mol) was refluxed for 6 h. The resulting solid was collected by filtration and heated in acetonitrile. Cooling of the resulting solution yielded large yellow cubes.
For (III), a solution of 3,4,5-trimethoxybenzaldehyde (4.704 g, 0.024 mol), ethylacetoacetate (6.24 g, 0.048 mol), and ammonium hydroxide (1.26 g, 0.036 mol) was refluxed in ethanol for 5 h and the solvent was removed. The remaining solid was heated in ethanol and the solution allowed to cool to room temperature, whereupon large colorless rhombs formed.
For all three compounds hydrogen atoms on the C2' and C6' methyl groups display disorder over two sets of positions. Each set of hydrogen positions was included in final refinement with 50% occupancy. For (III), the terminal methyl atom of the ethyl ester group at C3 displays disorder over two positions, C3"a and C3"b which were treated as half-populated and isotropic. The tetrahedral methylene atom C3" has one ordered hydrogen atom clearly visible and a second one which is disordered over two sites depending upon which version of the terminal methyl atom is present. This hydrogen atom was not located. H-atom positions were calculated using idealized geometry and a C—H distance of 0.97 Å.
For all compounds, data collection: XSCANS (Siemens, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990). Program(s) used to refine structure: SHELXL97 (Sheldrick, 1997) for (I), (II); SHELXS97 (Sheldrick, 1997) for (III). For all compounds, molecular graphics: XP (Siemens, 1990); software used to prepare material for publication: SHELXL97.
(I) 4-(2,5-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(ethoxycarbo nyl)
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Crystal data top
C21H27NO6 | F(000) = 832 |
Mr = 389.4 | Dx = 1.196 Mg m−3 Dm = not meas Mg m−3 Dm measured by ? |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 8.268 (4) Å | Cell parameters from 33 reflections |
b = 17.802 (7) Å | θ = 4.4–22.2° |
c = 14.707 (8) Å | µ = 0.09 mm−1 |
β = 93.32 (2)° | T = 301 K |
V = 2161 (2) Å3 | Cube, yellow |
Z = 4 | 0.1 × 0.1 × 0.1 mm |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.059 |
Radiation source: fine-focus sealed tube | θmax = 30.0°, θmin = 2.3° |
Highly oriented graphite crystal monochromator | h = −1→11 |
θ/2θ scans | k = −25→1 |
7927 measured reflections | l = −20→20 |
6302 independent reflections | 3 standard reflections every 97 reflections min |
2411 reflections with I > 2σ(I) | intensity decay: 0.0001% |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.071 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Fo2) + (0.1102P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.250 | (Δ/σ)max = 0.04 |
S = 1.01 | Δρmax = 0.19 e Å−3 |
6302 reflections | Δρmin = −0.23 e Å−3 |
254 parameters | |
Crystal data top
C21H27NO6 | V = 2161 (2) Å3 |
Mr = 389.4 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.268 (4) Å | µ = 0.09 mm−1 |
b = 17.802 (7) Å | T = 301 K |
c = 14.707 (8) Å | 0.1 × 0.1 × 0.1 mm |
β = 93.32 (2)° | |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.059 |
7927 measured reflections | 3 standard reflections every 97 reflections min |
6302 independent reflections | intensity decay: 0.0001% |
2411 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.071 | 0 restraints |
wR(F2) = 0.250 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.19 e Å−3 |
6302 reflections | Δρmin = −0.23 e Å−3 |
254 parameters | |
Special details top
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. For (I), (II) and (III), a variable scan rate, a θ-2θ scan mode with a scan width of 0.6° below Kα1 and 0.6° above Kα2 to a maximum 2θ value of 60°. Refinement was completed using full-matrix least-squares methods. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
N1 | 0.0502 (3) | 0.25955 (13) | 0.02486 (12) | 0.0601 (6) | |
H1A | 0.0206 | 0.2473 | −0.0424 | 0.080* | |
C2 | −0.0537 (3) | 0.23768 (13) | 0.09114 (15) | 0.0515 (6) | |
C2' | −0.2016 (4) | 0.19576 (16) | 0.05191 (18) | 0.0693 (8) | |
H2'A | −0.2690 | 0.1822 | 0.1003 | 0.080* | 0.50 |
H2'B | −0.2614 | 0.2275 | 0.0092 | 0.080* | 0.50 |
H2'C | −0.1680 | 0.1512 | 0.0215 | 0.080* | 0.50 |
H2'D | −0.1918 | 0.1965 | −0.0128 | 0.050* | 0.50 |
H2'E | −0.2995 | 0.2219 | 0.0643 | 0.050* | 0.50 |
H2'F | −0.2076 | 0.1442 | 0.0706 | 0.050* | 0.50 |
C3 | −0.0146 (3) | 0.25492 (13) | 0.18020 (14) | 0.0477 (5) | |
C3' | −0.1065 (3) | 0.23082 (14) | 0.25803 (16) | 0.0554 (6) | |
C3" | −0.3273 (5) | 0.1594 (2) | 0.3119 (2) | 0.1092 (14) | |
H3"A | −0.2574 | 0.1337 | 0.3560 | 0.080* | |
H3"B | −0.3763 | 0.2011 | 0.3412 | 0.080* | |
C3"' | −0.4483 (7) | 0.1076 (3) | 0.2788 (4) | 0.199 (3) | |
H3"C | −0.5119 | 0.0890 | 0.3265 | 0.080* | |
H3"D | −0.5172 | 0.1341 | 0.2348 | 0.080* | |
H3"E | −0.3976 | 0.0662 | 0.2497 | 0.080* | |
O3' | −0.0726 (3) | 0.25036 (13) | 0.33577 (11) | 0.0842 (7) | |
O3" | −0.2334 (2) | 0.18531 (11) | 0.23730 (12) | 0.0770 (6) | |
C4 | 0.1257 (3) | 0.30926 (13) | 0.20576 (15) | 0.0503 (6) | |
H4A | 0.1786 | 0.2921 | 0.2618 | 0.080* | |
C5 | 0.2504 (3) | 0.30841 (14) | 0.13140 (16) | 0.0528 (6) | |
C5' | 0.4153 (3) | 0.33755 (16) | 0.1544 (2) | 0.0668 (7) | |
C5" | 0.5923 (4) | 0.3919 (2) | 0.2716 (3) | 0.1061 (13) | |
H5"A | 0.6775 | 0.3554 | 0.2698 | 0.080* | |
H5"B | 0.6150 | 0.4321 | 0.2308 | 0.080* | |
C5"' | 0.5894 (5) | 0.4203 (3) | 0.3612 (3) | 0.1279 (16) | |
H5"C | 0.6906 | 0.4433 | 0.3806 | 0.080* | |
H5"D | 0.5042 | 0.4568 | 0.3622 | 0.080* | |
H5"E | 0.5671 | 0.3796 | 0.4015 | 0.080* | |
O5' | 0.5241 (3) | 0.34555 (16) | 0.10227 (17) | 0.1087 (9) | |
O5" | 0.4371 (2) | 0.35684 (13) | 0.24239 (14) | 0.0830 (6) | |
C6 | 0.2061 (3) | 0.28745 (14) | 0.04484 (16) | 0.0566 (7) | |
C6' | 0.3090 (4) | 0.28941 (17) | −0.03778 (19) | 0.0732 (8) | |
H6'A | 0.4146 | 0.3090 | −0.0207 | 0.080* | 0.50 |
H6'B | 0.3191 | 0.2394 | −0.0612 | 0.080* | 0.50 |
H6'C | 0.2573 | 0.3209 | −0.0838 | 0.080* | 0.50 |
H6'D | 0.2152 | 0.2776 | −0.0767 | 0.050* | 0.50 |
H6'E | 0.3396 | 0.3401 | −0.0508 | 0.050* | 0.50 |
H6'F | 0.4033 | 0.2595 | −0.0225 | 0.050* | 0.50 |
C7 | 0.0613 (3) | 0.38914 (14) | 0.22152 (17) | 0.0560 (6) | |
C8 | 0.0863 (4) | 0.42771 (17) | 0.30437 (19) | 0.0694 (8) | |
C9 | 0.0245 (4) | 0.50103 (19) | 0.3121 (2) | 0.0864 (10) | |
H9A | 0.0458 | 0.5280 | 0.3681 | 0.080* | |
C10 | −0.0623 (4) | 0.53421 (18) | 0.2403 (3) | 0.0889 (10) | |
H10A | −0.1050 | 0.5839 | 0.2470 | 0.080* | |
C11 | −0.0916 (4) | 0.49695 (17) | 0.1582 (2) | 0.0751 (8) | |
C12 | −0.0276 (3) | 0.42476 (14) | 0.14968 (19) | 0.0622 (7) | |
H12A | −0.0468 | 0.3984 | 0.0931 | 0.080* | |
O8 | 0.1708 (3) | 0.38995 (13) | 0.37481 (13) | 0.0875 (7) | |
C8' | 0.1824 (5) | 0.4239 (2) | 0.4625 (2) | 0.1115 (13) | |
H8'A | 0.2432 | 0.3917 | 0.5042 | 0.080* | |
H8'B | 0.2377 | 0.4710 | 0.4578 | 0.080* | |
H8'C | 0.0768 | 0.4324 | 0.4844 | 0.080* | |
O11 | −0.1821 (3) | 0.53461 (13) | 0.0910 (2) | 0.1055 (8) | |
C11' | −0.2442 (4) | 0.4926 (2) | 0.0141 (3) | 0.0987 (11) | |
H11A | −0.3048 | 0.5241 | −0.0286 | 0.080* | |
H11B | −0.1546 | 0.4707 | −0.0151 | 0.080* | |
H11C | −0.3130 | 0.4535 | 0.0348 | 0.080* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0707 (15) | 0.0751 (14) | 0.0351 (10) | −0.0010 (12) | 0.0086 (9) | −0.0001 (9) |
C2 | 0.0617 (15) | 0.0529 (13) | 0.0400 (11) | 0.0012 (12) | 0.0037 (11) | −0.0022 (10) |
C2' | 0.0802 (19) | 0.0778 (18) | 0.0493 (14) | −0.0072 (16) | −0.0019 (13) | −0.0103 (13) |
C3 | 0.0551 (14) | 0.0491 (13) | 0.0392 (11) | 0.0005 (11) | 0.0059 (10) | 0.0000 (10) |
C3' | 0.0616 (15) | 0.0591 (14) | 0.0458 (13) | −0.0030 (13) | 0.0074 (11) | 0.0019 (11) |
C3" | 0.121 (3) | 0.118 (3) | 0.093 (3) | −0.048 (3) | 0.054 (2) | −0.004 (2) |
C3"' | 0.213 (6) | 0.224 (6) | 0.174 (5) | −0.143 (5) | 0.117 (5) | −0.082 (5) |
O3' | 0.0968 (15) | 0.1200 (17) | 0.0367 (9) | −0.0301 (13) | 0.0108 (9) | −0.0027 (10) |
O3" | 0.0840 (14) | 0.0870 (13) | 0.0617 (11) | −0.0296 (12) | 0.0199 (10) | −0.0050 (10) |
C4 | 0.0572 (14) | 0.0535 (13) | 0.0406 (11) | −0.0021 (12) | 0.0066 (10) | −0.0028 (10) |
C5 | 0.0564 (15) | 0.0525 (13) | 0.0505 (13) | 0.0043 (12) | 0.0125 (11) | 0.0018 (11) |
C5' | 0.0547 (16) | 0.0646 (17) | 0.083 (2) | 0.0038 (14) | 0.0174 (15) | −0.0007 (15) |
C5" | 0.057 (2) | 0.125 (3) | 0.136 (3) | −0.017 (2) | 0.000 (2) | −0.024 (3) |
C5"' | 0.103 (3) | 0.154 (4) | 0.121 (3) | −0.038 (3) | −0.041 (3) | 0.010 (3) |
O5' | 0.0720 (14) | 0.143 (2) | 0.1147 (19) | −0.0240 (14) | 0.0397 (14) | −0.0227 (16) |
O5" | 0.0558 (12) | 0.1123 (17) | 0.0809 (14) | −0.0112 (11) | 0.0037 (10) | −0.0149 (12) |
C6 | 0.0650 (17) | 0.0540 (14) | 0.0525 (14) | 0.0096 (13) | 0.0192 (12) | 0.0046 (11) |
C6' | 0.080 (2) | 0.0795 (19) | 0.0629 (16) | 0.0051 (16) | 0.0262 (14) | 0.0035 (14) |
C7 | 0.0561 (15) | 0.0574 (14) | 0.0564 (14) | −0.0053 (12) | 0.0186 (12) | −0.0089 (12) |
C8 | 0.0697 (18) | 0.0727 (19) | 0.0672 (17) | −0.0087 (15) | 0.0157 (15) | −0.0226 (15) |
C9 | 0.089 (2) | 0.078 (2) | 0.094 (2) | −0.0130 (19) | 0.0243 (19) | −0.0378 (19) |
C10 | 0.092 (2) | 0.0565 (18) | 0.122 (3) | −0.0019 (17) | 0.035 (2) | −0.0203 (19) |
C11 | 0.077 (2) | 0.0584 (17) | 0.092 (2) | 0.0017 (16) | 0.0230 (17) | 0.0060 (16) |
C12 | 0.0657 (17) | 0.0531 (15) | 0.0696 (17) | 0.0001 (13) | 0.0189 (14) | −0.0006 (13) |
O8 | 0.0969 (16) | 0.1005 (16) | 0.0645 (13) | 0.0005 (13) | −0.0007 (11) | −0.0310 (12) |
C8' | 0.149 (3) | 0.115 (3) | 0.071 (2) | −0.010 (3) | 0.006 (2) | −0.034 (2) |
O11 | 0.124 (2) | 0.0677 (14) | 0.125 (2) | 0.0242 (14) | 0.0088 (17) | 0.0129 (14) |
C11' | 0.090 (2) | 0.091 (2) | 0.115 (3) | 0.015 (2) | 0.016 (2) | 0.040 (2) |
Geometric parameters (Å, º) top
N1—C2 | 1.392 (3) | C5"—H5"A | 0.9600 |
N1—C6 | 1.397 (3) | C5"—H5"B | 0.9600 |
N1—H1A | 1.0282 | C5"'—H5"C | 0.9600 |
C2—C3 | 1.366 (3) | C5"'—H5"D | 0.9600 |
C2—C2' | 1.517 (4) | C5"'—H5"E | 0.9600 |
C2'—H2'A | 0.9600 | C6—C6' | 1.523 (3) |
C2'—H2'B | 0.9600 | C6'—H6'A | 0.9600 |
C2'—H2'C | 0.9600 | C6'—H6'B | 0.9599 |
C2'—H2'D | 0.9600 | C6'—H6'C | 0.9601 |
C2'—H2'E | 0.9600 | C6'—H6'D | 0.9600 |
C2'—H2'F | 0.9600 | C6'—H6'E | 0.9600 |
C3—C3' | 1.474 (3) | C6'—H6'F | 0.9600 |
C3—C4 | 1.540 (3) | C7—C12 | 1.403 (4) |
C3'—O3' | 1.212 (3) | C7—C8 | 1.403 (4) |
C3'—O3" | 1.347 (3) | C8—O8 | 1.389 (4) |
C3"—C3"' | 1.426 (5) | C8—C9 | 1.409 (5) |
C3"—O3" | 1.455 (3) | C9—C10 | 1.375 (5) |
C3"—H3"A | 0.9600 | C9—H9A | 0.9600 |
C3"—H3"B | 0.9599 | C10—C11 | 1.387 (4) |
C3"'—H3"C | 0.9600 | C10—H10A | 0.9600 |
C3"'—H3"D | 0.9599 | C11—O11 | 1.379 (4) |
C3"'—H3"E | 0.9601 | C11—C12 | 1.398 (4) |
C4—C7 | 1.541 (3) | C12—H12A | 0.9600 |
C4—C5 | 1.546 (3) | O8—C8' | 1.423 (3) |
C4—H4A | 0.9600 | C8'—H8'A | 0.9599 |
C5—C6 | 1.356 (3) | C8'—H8'B | 0.9600 |
C5—C5' | 1.480 (4) | C8'—H8'C | 0.9600 |
C5'—O5' | 1.224 (3) | O11—C11' | 1.427 (4) |
C5'—O5" | 1.340 (3) | C11'—H11A | 0.9599 |
C5"—C5"' | 1.412 (5) | C11'—H11B | 0.9600 |
C5"—O5" | 1.469 (4) | C11'—H11C | 0.9600 |
| | | |
C2—N1—C6 | 123.48 (19) | C5"—C5"'—H5"C | 111.6 |
C2—N1—H1A | 119.5 | C5"—C5"'—H5"D | 108.0 |
C6—N1—H1A | 116.3 | H5"C—C5"'—H5"D | 109.5 |
C3—C2—N1 | 119.2 (2) | C5"—C5"'—H5"E | 108.8 |
C3—C2—C2' | 128.0 (2) | H5"C—C5"'—H5"E | 109.5 |
N1—C2—C2' | 112.8 (2) | H5"D—C5"'—H5"E | 109.5 |
C2—C2'—H2'A | 109.4 | C5'—O5"—C5" | 117.2 (2) |
C2—C2'—H2'B | 109.4 | C5—C6—N1 | 119.4 (2) |
H2'A—C2'—H2'B | 109.5 | C5—C6—C6' | 127.5 (3) |
C2—C2'—H2'C | 109.6 | N1—C6—C6' | 113.0 (2) |
H2'A—C2'—H2'C | 109.5 | C6—C6'—H6'A | 109.9 |
H2'B—C2'—H2'C | 109.5 | C6—C6'—H6'B | 109.2 |
C2—C2'—H2'D | 105.0 | H6'A—C6'—H6'B | 109.5 |
H2'A—C2'—H2'D | 145.5 | C6—C6'—H6'C | 109.3 |
H2'B—C2'—H2'D | 54.1 | H6'A—C6'—H6'C | 109.5 |
H2'C—C2'—H2'D | 60.4 | H6'B—C6'—H6'C | 109.5 |
C2—C2'—H2'E | 111.0 | C6—C6'—H6'D | 90.1 |
H2'A—C2'—H2'E | 56.5 | H6'A—C6'—H6'D | 157.9 |
H2'B—C2'—H2'E | 55.3 | H6'B—C6'—H6'D | 70.6 |
H2'C—C2'—H2'E | 139.3 | H6'C—C6'—H6'D | 52.9 |
H2'D—C2'—H2'E | 107.6 | C6—C6'—H6'E | 110.3 |
C2—C2'—H2'F | 114.5 | H6'A—C6'—H6'E | 57.6 |
H2'A—C2'—H2'F | 60.3 | H6'B—C6'—H6'E | 140.5 |
H2'B—C2'—H2'F | 135.8 | H6'C—C6'—H6'E | 54.7 |
H2'C—C2'—H2'F | 50.6 | H6'D—C6'—H6'E | 107.5 |
H2'D—C2'—H2'F | 107.8 | C6—C6'—H6'F | 106.5 |
H2'E—C2'—H2'F | 110.5 | H6'A—C6'—H6'F | 55.0 |
C2—C3—C3' | 125.1 (2) | H6'B—C6'—H6'F | 58.9 |
C2—C3—C4 | 120.56 (19) | H6'C—C6'—H6'F | 144.2 |
C3'—C3—C4 | 114.09 (19) | H6'D—C6'—H6'F | 129.4 |
O3'—C3'—O3" | 121.4 (2) | H6'E—C6'—H6'F | 110.4 |
O3'—C3'—C3 | 123.2 (2) | C12—C7—C8 | 118.5 (3) |
O3"—C3'—C3 | 115.4 (2) | C12—C7—C4 | 118.3 (2) |
C3"'—C3"—O3" | 110.0 (3) | C8—C7—C4 | 123.2 (3) |
C3"'—C3"—H3"A | 107.7 | O8—C8—C7 | 117.0 (3) |
O3"—C3"—H3"A | 109.5 | O8—C8—C9 | 123.8 (3) |
C3"'—C3"—H3"B | 110.4 | C7—C8—C9 | 119.2 (3) |
O3"—C3"—H3"B | 110.5 | C10—C9—C8 | 120.8 (3) |
H3"A—C3"—H3"B | 108.6 | C10—C9—H9A | 120.4 |
C3"—C3"'—H3"C | 112.1 | C8—C9—H9A | 118.9 |
C3"—C3"'—H3"D | 106.8 | C9—C10—C11 | 121.4 (3) |
H3"C—C3"'—H3"D | 109.5 | C9—C10—H10A | 119.8 |
C3"—C3"'—H3"E | 109.4 | C11—C10—H10A | 118.8 |
H3"C—C3"'—H3"E | 109.5 | O11—C11—C10 | 116.9 (3) |
H3"D—C3"'—H3"E | 109.5 | O11—C11—C12 | 125.1 (3) |
C3'—O3"—C3" | 117.6 (2) | C10—C11—C12 | 118.0 (3) |
C3—C4—C7 | 110.74 (19) | C11—C12—C7 | 122.2 (3) |
C3—C4—C5 | 110.18 (18) | C11—C12—H12A | 118.8 |
C7—C4—C5 | 111.47 (19) | C7—C12—H12A | 119.0 |
C3—C4—H4A | 108.0 | C8—O8—C8' | 118.4 (3) |
C7—C4—H4A | 107.9 | O8—C8'—H8'A | 109.3 |
C5—C4—H4A | 108.4 | O8—C8'—H8'B | 108.2 |
C6—C5—C5' | 120.4 (2) | H8'A—C8'—H8'B | 109.5 |
C6—C5—C4 | 120.8 (2) | O8—C8'—H8'C | 110.9 |
C5'—C5—C4 | 118.6 (2) | H8'A—C8'—H8'C | 109.5 |
O5'—C5'—O5" | 120.9 (3) | H8'B—C8'—H8'C | 109.5 |
O5'—C5'—C5 | 126.7 (3) | C11—O11—C11' | 118.0 (3) |
O5"—C5'—C5 | 112.4 (2) | O11—C11'—H11A | 111.3 |
C5"'—C5"—O5" | 111.3 (3) | O11—C11'—H11B | 108.4 |
C5"'—C5"—H5"A | 108.7 | H11A—C11'—H11B | 109.5 |
O5"—C5"—H5"A | 109.5 | O11—C11'—H11C | 108.7 |
C5"'—C5"—H5"B | 109.4 | H11A—C11'—H11C | 109.5 |
O5"—C5"—H5"B | 109.4 | H11B—C11'—H11C | 109.5 |
H5"A—C5"—H5"B | 108.4 | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3′i | 1.03 | 1.91 | 2.910 (3) | 163 |
Symmetry code: (i) x, −y+1/2, z−1/2. |
(II) 4-(3,4-dimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(ethoxycarbo nyl)
top
Crystal data top
C21H27NO6 | F(000) = 832 |
Mr = 389.4 | Dx = 1.198 Mg m−3 Dm = not meas Mg m−3 Dm measured by ? |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 8.462 (6) Å | Cell parameters from 97 reflections |
b = 7.637 (6) Å | θ = 4.2–12.7° |
c = 33.44 (2) Å | µ = 0.09 mm−1 |
β = 94.48 (2)° | T = 301 K |
V = 2154 (3) Å3 | Cube, yellow |
Z = 4 | 0.1 × 0.1 × 0.1 mm |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.062 |
Radiation source: fine-focus sealed tube | θmax = 30.1°, θmin = 2.4° |
Highly oriented graphite crystal monochromator | h = −1→10 |
θ/2θ scans | k = −10→1 |
8355 measured reflections | l = −47→47 |
6261 independent reflections | 3 standard reflections every 97 reflections min |
2644 reflections with I > 2σ(I) | intensity decay: <1% |
Refinement top
Refinement on F2 | 253 parameters |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.085 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Fo2) + (0.1016P)2 + 1.0333P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.263 | (Δ/σ)max = 0.003 |
S = 1.01 | Δρmax = 0.21 e Å−3 |
6261 reflections | Δρmin = −0.22 e Å−3 |
Crystal data top
C21H27NO6 | V = 2154 (3) Å3 |
Mr = 389.4 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.462 (6) Å | µ = 0.09 mm−1 |
b = 7.637 (6) Å | T = 301 K |
c = 33.44 (2) Å | 0.1 × 0.1 × 0.1 mm |
β = 94.48 (2)° | |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.062 |
8355 measured reflections | 3 standard reflections every 97 reflections min |
6261 independent reflections | intensity decay: <1% |
2644 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.085 | 253 parameters |
wR(F2) = 0.263 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.21 e Å−3 |
6261 reflections | Δρmin = −0.22 e Å−3 |
Special details top
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
N1 | 0.6103 (3) | 0.2254 (4) | 0.07405 (8) | 0.0558 (7) | |
H1A | 0.5727 | 0.1152 | 0.0723 | 0.080* | |
C2 | 0.7702 (4) | 0.2517 (4) | 0.08874 (9) | 0.0510 (8) | |
C2' | 0.8669 (5) | 0.0829 (5) | 0.08919 (13) | 0.0689 (10) | |
H2'F | 0.8045 | −0.0190 | 0.0821 | 0.080* | 0.50 |
H2'A | 0.9740 | 0.1071 | 0.0993 | 0.080* | 0.50 |
H2'B | 0.8213 | −0.0014 | 0.1062 | 0.080* | 0.50 |
H2'C | 0.8664 | 0.0367 | 0.0625 | 0.080* | 0.50 |
H2'D | 0.9243 | 0.0790 | 0.1151 | 0.080* | 0.50 |
H2'E | 0.9592 | 0.0986 | 0.0746 | 0.080* | 0.50 |
C3 | 0.8186 (3) | 0.4162 (4) | 0.09975 (9) | 0.0448 (7) | |
C3' | 0.9890 (4) | 0.4505 (5) | 0.11289 (9) | 0.0567 (9) | |
C3" | 1.1745 (4) | 0.6578 (8) | 0.14204 (14) | 0.108 (2) | |
H3"A | 1.2238 | 0.5524 | 0.1525 | 0.080* | |
H3"E | 1.2347 | 0.6980 | 0.1207 | 0.080* | |
C3"' | 1.1800 (7) | 0.7878 (11) | 0.1700 (3) | 0.239 (6) | |
H3"B | 1.2891 | 0.8071 | 0.1791 | 0.080* | |
H3"C | 1.1308 | 0.8977 | 0.1627 | 0.080* | |
H3"D | 1.1260 | 0.7350 | 0.1912 | 0.080* | |
O3' | 1.0976 (3) | 0.3428 (4) | 0.11432 (9) | 0.0835 (9) | |
O3" | 1.0135 (3) | 0.6201 (4) | 0.12421 (8) | 0.0731 (8) | |
C4 | 0.6966 (3) | 0.5655 (4) | 0.10266 (8) | 0.0436 (7) | |
H4A | 0.7451 | 0.6729 | 0.0951 | 0.080* | |
C5 | 0.5497 (3) | 0.5313 (4) | 0.07315 (9) | 0.0446 (7) | |
C5' | 0.4599 (4) | 0.6917 (4) | 0.05979 (9) | 0.0467 (7) | |
C5" | 0.2149 (4) | 0.8117 (5) | 0.02954 (11) | 0.0628 (9) | |
H5"A | 0.2063 | 0.8897 | 0.0518 | 0.080* | |
H5"B | 0.2614 | 0.8738 | 0.0084 | 0.080* | |
C5"' | 0.0522 (4) | 0.7417 (5) | 0.01464 (12) | 0.0713 (11) | |
H5"C | −0.0172 | 0.8361 | 0.0060 | 0.080* | |
H5"D | 0.0637 | 0.6634 | −0.0074 | 0.080* | |
H5"E | 0.0084 | 0.6794 | 0.0361 | 0.080* | |
O5' | 0.5107 (3) | 0.8432 (3) | 0.06461 (8) | 0.0682 (7) | |
O5" | 0.3126 (3) | 0.6609 (3) | 0.04196 (7) | 0.0605 (6) | |
C6 | 0.5079 (4) | 0.3635 (4) | 0.06207 (9) | 0.0468 (7) | |
C6' | 0.3592 (4) | 0.2999 (5) | 0.03765 (11) | 0.0611 (9) | |
H6'A | 0.2931 | 0.3984 | 0.0300 | 0.080* | 0.50 |
H6'B | 0.3883 | 0.2405 | 0.0140 | 0.080* | 0.50 |
H6'C | 0.3023 | 0.2209 | 0.0536 | 0.080* | 0.50 |
H6'D | 0.3398 | 0.3663 | 0.0134 | 0.080* | 0.50 |
H6'E | 0.2659 | 0.3280 | 0.0509 | 0.080* | 0.50 |
H6'F | 0.3685 | 0.1784 | 0.0309 | 0.080* | 0.50 |
C7 | 0.6495 (3) | 0.5859 (4) | 0.14644 (9) | 0.0436 (7) | |
C8 | 0.5545 (3) | 0.4566 (4) | 0.16350 (9) | 0.0473 (7) | |
H8A | 0.5180 | 0.3577 | 0.1476 | 0.080* | |
C9 | 0.5152 (3) | 0.4696 (5) | 0.20347 (9) | 0.0503 (8) | |
C10 | 0.5710 (4) | 0.6134 (5) | 0.22743 (9) | 0.0554 (9) | |
C11 | 0.6652 (4) | 0.7413 (5) | 0.21087 (10) | 0.0620 (9) | |
H11A | 0.7033 | 0.8394 | 0.2268 | 0.080* | |
C12 | 0.7035 (4) | 0.7264 (5) | 0.17055 (10) | 0.0567 (8) | |
H12A | 0.7696 | 0.8136 | 0.1596 | 0.080* | |
C13 | 0.3753 (5) | 0.1913 (6) | 0.20142 (14) | 0.0810 (12) | |
H13A | 0.3119 | 0.1205 | 0.2177 | 0.080* | |
H13B | 0.3153 | 0.2195 | 0.1767 | 0.080* | |
H13C | 0.4690 | 0.1279 | 0.1958 | 0.080* | |
C14 | 0.5691 (6) | 0.7598 (8) | 0.29088 (13) | 0.114 (2) | |
H14A | 0.5299 | 0.7453 | 0.3169 | 0.080* | |
H14B | 0.6824 | 0.7712 | 0.2937 | 0.080* | |
H14C | 0.5235 | 0.8632 | 0.2784 | 0.080* | |
O9 | 0.4218 (3) | 0.3501 (4) | 0.22243 (7) | 0.0746 (8) | |
O10 | 0.5241 (3) | 0.6147 (4) | 0.26638 (7) | 0.0760 (8) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0567 (16) | 0.0424 (16) | 0.0678 (17) | 0.0027 (13) | 0.0027 (13) | −0.0002 (13) |
C2 | 0.0503 (17) | 0.050 (2) | 0.0535 (17) | 0.0126 (15) | 0.0094 (14) | 0.0079 (15) |
C2' | 0.069 (2) | 0.057 (2) | 0.081 (2) | 0.0191 (19) | 0.0084 (18) | 0.006 (2) |
C3 | 0.0419 (15) | 0.0491 (19) | 0.0441 (14) | 0.0074 (14) | 0.0080 (12) | 0.0074 (14) |
C3' | 0.0480 (17) | 0.076 (3) | 0.0469 (16) | 0.0102 (18) | 0.0115 (13) | 0.0082 (18) |
C3" | 0.043 (2) | 0.188 (6) | 0.092 (3) | −0.015 (3) | −0.0001 (19) | −0.038 (4) |
C3"' | 0.070 (4) | 0.252 (10) | 0.379 (14) | 0.041 (5) | −0.077 (6) | −0.206 (11) |
O3' | 0.0478 (13) | 0.093 (2) | 0.111 (2) | 0.0220 (15) | 0.0142 (13) | 0.0177 (18) |
O3" | 0.0397 (12) | 0.094 (2) | 0.0850 (17) | 0.0029 (13) | −0.0020 (11) | −0.0219 (16) |
C4 | 0.0409 (14) | 0.0420 (17) | 0.0478 (15) | 0.0012 (13) | 0.0024 (12) | 0.0044 (13) |
C5 | 0.0478 (16) | 0.0415 (17) | 0.0443 (15) | 0.0040 (14) | 0.0031 (12) | 0.0004 (13) |
C5' | 0.0497 (17) | 0.0454 (19) | 0.0445 (15) | 0.0048 (15) | −0.0010 (12) | −0.0043 (14) |
C5" | 0.065 (2) | 0.049 (2) | 0.071 (2) | 0.0102 (17) | −0.0141 (17) | −0.0015 (17) |
C5"' | 0.062 (2) | 0.070 (3) | 0.079 (2) | 0.010 (2) | −0.0146 (18) | 0.003 (2) |
O5' | 0.0634 (15) | 0.0439 (14) | 0.0935 (18) | 0.0039 (12) | −0.0177 (13) | −0.0035 (13) |
O5" | 0.0581 (13) | 0.0453 (13) | 0.0743 (15) | 0.0073 (11) | −0.0191 (11) | −0.0016 (11) |
C6 | 0.0510 (17) | 0.0418 (18) | 0.0475 (15) | 0.0061 (15) | 0.0040 (13) | −0.0007 (14) |
C6' | 0.061 (2) | 0.051 (2) | 0.069 (2) | 0.0010 (17) | −0.0072 (16) | −0.0123 (18) |
C7 | 0.0368 (14) | 0.0463 (17) | 0.0473 (15) | 0.0049 (13) | 0.0009 (11) | −0.0010 (14) |
C8 | 0.0426 (15) | 0.0483 (18) | 0.0502 (16) | 0.0022 (14) | −0.0018 (12) | −0.0041 (14) |
C9 | 0.0406 (15) | 0.058 (2) | 0.0520 (17) | −0.0004 (15) | 0.0026 (13) | −0.0012 (16) |
C10 | 0.0451 (16) | 0.076 (2) | 0.0452 (16) | 0.0031 (17) | 0.0026 (13) | −0.0092 (17) |
C11 | 0.0542 (18) | 0.069 (2) | 0.063 (2) | −0.0147 (18) | 0.0070 (15) | −0.0220 (18) |
C12 | 0.0539 (18) | 0.058 (2) | 0.0589 (18) | −0.0091 (17) | 0.0085 (14) | −0.0098 (17) |
C13 | 0.082 (3) | 0.067 (3) | 0.096 (3) | −0.019 (2) | 0.017 (2) | 0.004 (2) |
C14 | 0.130 (4) | 0.150 (5) | 0.067 (3) | −0.050 (4) | 0.033 (3) | −0.045 (3) |
O9 | 0.0832 (17) | 0.0770 (19) | 0.0660 (15) | −0.0265 (15) | 0.0221 (13) | −0.0032 (14) |
O10 | 0.0784 (17) | 0.098 (2) | 0.0529 (13) | −0.0142 (16) | 0.0153 (12) | −0.0173 (14) |
Geometric parameters (Å, º) top
N1—C6 | 1.403 (4) | C5"—H5"A | 0.9601 |
N1—C2 | 1.417 (4) | C5"—H5"B | 0.9600 |
N1—H1A | 0.9000 | C5"'—H5"C | 0.9600 |
C2—C3 | 1.364 (5) | C5"'—H5"D | 0.9599 |
C2—C2' | 1.526 (5) | C5"'—H5"E | 0.9600 |
C2'—H2'F | 0.9600 | C6—C6' | 1.524 (4) |
C2'—H2'A | 0.9600 | C6'—H6'A | 0.9600 |
C2'—H2'B | 0.9600 | C6'—H6'B | 0.9601 |
C2'—H2'C | 0.9601 | C6'—H6'C | 0.9600 |
C2'—H2'D | 0.9599 | C6'—H6'D | 0.9601 |
C2'—H2'E | 0.9599 | C6'—H6'E | 0.9599 |
C3—C3' | 1.496 (4) | C6'—H6'F | 0.9600 |
C3—C4 | 1.546 (4) | C7—C12 | 1.397 (4) |
C3'—O3' | 1.232 (4) | C7—C8 | 1.421 (4) |
C3'—O3" | 1.361 (5) | C8—C9 | 1.405 (4) |
C3"—C3"' | 1.3623 (12) | C8—H8A | 0.9600 |
C3"—O3" | 1.472 (4) | C9—O9 | 1.393 (4) |
C3"—H3"A | 0.9601 | C9—C10 | 1.418 (5) |
C3"—H3"E | 0.9599 | C10—O10 | 1.392 (4) |
C3"'—H3"B | 0.9600 | C10—C11 | 1.402 (5) |
C3"'—H3"C | 0.9600 | C11—C12 | 1.416 (5) |
C3"'—H3"D | 0.9601 | C11—H11A | 0.9600 |
C4—C5 | 1.547 (4) | C12—H12A | 0.9600 |
C4—C7 | 1.555 (4) | C13—O9 | 1.441 (5) |
C4—H4A | 0.9600 | C13—H13A | 0.9600 |
C5—C6 | 1.373 (4) | C13—H13B | 0.9599 |
C5—C5' | 1.492 (4) | C13—H13C | 0.9600 |
C5'—O5' | 1.240 (4) | C14—O10 | 1.413 (5) |
C5'—O5" | 1.359 (4) | C14—H14A | 0.9600 |
C5"—O5" | 1.458 (4) | C14—H14B | 0.9600 |
C5"—C5"' | 1.524 (5) | C14—H14C | 0.9600 |
| | | |
C6—N1—C2 | 123.0 (3) | C5"—C5"'—H5"C | 110.5 |
C6—N1—H1A | 118.4 | C5"—C5"'—H5"D | 109.1 |
C2—N1—H1A | 118.6 | H5"C—C5"'—H5"D | 109.5 |
C3—C2—N1 | 118.9 (3) | C5"—C5"'—H5"E | 108.8 |
C3—C2—C2' | 128.7 (3) | H5"C—C5"'—H5"E | 109.5 |
N1—C2—C2' | 112.4 (3) | H5"D—C5"'—H5"E | 109.5 |
C2—C2'—H2'F | 113.4 | C5'—O5"—C5" | 117.9 (3) |
C2—C2'—H2'A | 109.3 | C5—C6—N1 | 118.9 (3) |
H2'F—C2'—H2'A | 136.9 | C5—C6—C6' | 128.8 (3) |
C2—C2'—H2'B | 109.4 | N1—C6—C6' | 112.3 (3) |
H2'F—C2'—H2'B | 50.6 | C6—C6'—H6'A | 109.4 |
H2'A—C2'—H2'B | 109.5 | C6—C6'—H6'B | 109.7 |
C2—C2'—H2'C | 109.6 | H6'A—C6'—H6'B | 109.5 |
H2'F—C2'—H2'C | 60.6 | C6—C6'—H6'C | 109.3 |
H2'A—C2'—H2'C | 109.5 | H6'A—C6'—H6'C | 109.5 |
H2'B—C2'—H2'C | 109.5 | H6'B—C6'—H6'C | 109.5 |
C2—C2'—H2'D | 105.6 | C6—C6'—H6'D | 111.3 |
H2'F—C2'—H2'D | 115.4 | H6'A—C6'—H6'D | 45.9 |
H2'A—C2'—H2'D | 44.9 | H6'B—C6'—H6'D | 65.9 |
H2'B—C2'—H2'D | 69.1 | H6'C—C6'—H6'D | 137.9 |
H2'C—C2'—H2'D | 142.5 | C6—C6'—H6'E | 110.8 |
C2—C2'—H2'E | 110.2 | H6'A—C6'—H6'E | 57.6 |
H2'F—C2'—H2'E | 115.4 | H6'B—C6'—H6'E | 139.4 |
H2'A—C2'—H2'E | 51.0 | H6'C—C6'—H6'E | 54.3 |
H2'B—C2'—H2'E | 140.0 | H6'D—C6'—H6'E | 100.3 |
H2'C—C2'—H2'E | 61.2 | C6—C6'—H6'F | 110.8 |
H2'D—C2'—H2'E | 95.0 | H6'A—C6'—H6'F | 138.7 |
C2—C3—C3' | 120.2 (3) | H6'B—C6'—H6'F | 47.0 |
C2—C3—C4 | 120.5 (3) | H6'C—C6'—H6'F | 65.0 |
C3'—C3—C4 | 119.1 (3) | H6'D—C6'—H6'F | 108.8 |
O3'—C3'—O3" | 121.8 (3) | H6'E—C6'—H6'F | 114.3 |
O3'—C3'—C3 | 126.4 (4) | C12—C7—C8 | 118.2 (3) |
O3"—C3'—C3 | 111.8 (3) | C12—C7—C4 | 121.6 (3) |
C3"'—C3"—O3" | 113.7 (4) | C8—C7—C4 | 120.2 (3) |
C3"'—C3"—H3"A | 111.9 | C9—C8—C7 | 121.0 (3) |
O3"—C3"—H3"A | 110.2 | C9—C8—H8A | 119.4 |
C3"'—C3"—H3"E | 106.4 | C7—C8—H8A | 119.6 |
O3"—C3"—H3"E | 106.8 | O9—C9—C8 | 124.8 (3) |
H3"A—C3"—H3"E | 107.3 | O9—C9—C10 | 115.3 (3) |
C3"—C3"'—H3"B | 108.1 | C8—C9—C10 | 119.9 (3) |
C3"—C3"'—H3"C | 118.3 | O10—C10—C11 | 125.3 (3) |
H3"B—C3"'—H3"C | 109.5 | O10—C10—C9 | 115.3 (3) |
C3"—C3"'—H3"D | 101.6 | C11—C10—C9 | 119.4 (3) |
H3"B—C3"'—H3"D | 109.5 | C10—C11—C12 | 120.0 (3) |
H3"C—C3"'—H3"D | 109.5 | C10—C11—H11A | 120.1 |
C3'—O3"—C3" | 114.5 (3) | C12—C11—H11A | 119.9 |
C5—C4—C3 | 110.0 (3) | C7—C12—C11 | 121.5 (3) |
C5—C4—C7 | 111.4 (2) | C7—C12—H12A | 119.1 |
C3—C4—C7 | 110.8 (2) | C11—C12—H12A | 119.4 |
C5—C4—H4A | 108.4 | O9—C13—H13A | 110.0 |
C3—C4—H4A | 108.1 | O9—C13—H13B | 109.6 |
C7—C4—H4A | 108.0 | H13A—C13—H13B | 109.5 |
C6—C5—C5' | 124.8 (3) | O9—C13—H13C | 108.8 |
C6—C5—C4 | 120.5 (3) | H13A—C13—H13C | 109.5 |
C5'—C5—C4 | 114.7 (3) | H13B—C13—H13C | 109.5 |
O5'—C5'—O5" | 121.0 (3) | O10—C14—H14A | 109.7 |
O5'—C5'—C5 | 124.3 (3) | O10—C14—H14B | 110.5 |
O5"—C5'—C5 | 114.7 (3) | H14A—C14—H14B | 109.5 |
O5"—C5"—C5"' | 107.0 (3) | O10—C14—H14C | 108.2 |
O5"—C5"—H5"A | 110.2 | H14A—C14—H14C | 109.5 |
C5"'—C5"—H5"A | 110.4 | H14B—C14—H14C | 109.5 |
O5"—C5"—H5"B | 110.1 | C9—O9—C13 | 118.3 (3) |
C5"'—C5"—H5"B | 110.2 | C10—O10—C14 | 117.7 (3) |
H5"A—C5"—H5"B | 108.9 | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O5′i | 0.90 | 2.15 | 3.048 (4) | 173 |
Symmetry code: (i) x, y−1, z. |
(III) 4-(3,4,5-trimethoxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(ethoxyca rbonyl) (III)
top
Crystal data top
C22H29NO7 | Dx = 1.164 Mg m−3 Dm = not meas Mg m−3 Dm measured by ? |
Mr = 419.46 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 46 reflections |
a = 8.714 (8) Å | θ = 4.1–12.8° |
b = 16.167 (14) Å | µ = 0.09 mm−1 |
c = 16.948 (14) Å | T = 301 K |
V = 2388 (5) Å3 | Rhomb, colorless |
Z = 4 | 0.3 × 0.2 × 0.2 mm |
F(000) = 892 | |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.041 |
Radiation source: fine-focus sealed tube | θmax = 30.0°, θmin = 2.4° |
Highly oriented graphite crystal monochromator | h = −12→1 |
θ/2θ scans | k = −22→1 |
4844 measured reflections | l = −1→23 |
4634 independent reflections | 3 standard reflections every 97 reflections min |
2616 reflections with I<2σ(I) | intensity decay: <1% |
Refinement top
Refinement on F2 | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.069 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Fo2) + (0.1102P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.220 | (Δ/σ)max = 0.045 |
S = 1.00 | Δρmax = 0.34 e Å−3 |
4634 reflections | Δρmin = −0.28 e Å−3 |
270 parameters | |
Crystal data top
C22H29NO7 | V = 2388 (5) Å3 |
Mr = 419.46 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 8.714 (8) Å | µ = 0.09 mm−1 |
b = 16.167 (14) Å | T = 301 K |
c = 16.948 (14) Å | 0.3 × 0.2 × 0.2 mm |
Data collection top
Syntex P4 4-circle- diffractometer | Rint = 0.041 |
4844 measured reflections | 3 standard reflections every 97 reflections min |
4634 independent reflections | intensity decay: <1% |
2616 reflections with I<2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.069 | 270 parameters |
wR(F2) = 0.220 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.34 e Å−3 |
4634 reflections | Δρmin = −0.28 e Å−3 |
Special details top
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
N1 | 0.1083 (4) | 0.22006 (19) | 0.15745 (19) | 0.0613 (9) | |
H1A | 0.0601 | 0.2510 | 0.1940 | 0.080* | |
C2 | 0.0294 (5) | 0.1999 (2) | 0.0891 (2) | 0.0566 (9) | |
C2' | −0.1108 (7) | 0.2544 (3) | 0.0738 (3) | 0.0850 (15) | |
H2'A | −0.1592 | 0.2372 | 0.0267 | 0.080* | 0.50 |
H2'B | −0.1826 | 0.2474 | 0.1179 | 0.080* | 0.50 |
H2'C | −0.0827 | 0.3115 | 0.0713 | 0.080* | 0.50 |
H2'D | −0.2038 | 0.2219 | 0.0747 | 0.080* | 0.50 |
H2'E | −0.1502 | 0.2879 | 0.0328 | 0.080* | 0.50 |
H2'F | −0.1580 | 0.2930 | 0.1109 | 0.080* | 0.50 |
C3 | 0.0838 (5) | 0.1376 (2) | 0.0422 (2) | 0.0504 (8) | |
C3' | 0.0101 (6) | 0.1181 (3) | −0.0353 (2) | 0.0644 (11) | |
C3" | 0.0401 (10) | 0.0372 (5) | −0.1528 (4) | 0.124 (2) | |
H3"H | 0.1157 | 0.0431 | −0.1936 | 0.080* | 0.50 |
H3"G | 0.0396 | −0.0221 | −0.1564 | 0.080* | 0.50 |
H3 | −0.0545 | 0.0629 | −0.1682 | 0.080* | |
O3' | −0.1156 (5) | 0.1403 (3) | −0.0585 (2) | 0.1045 (13) | |
O3" | 0.0992 (5) | 0.0675 (2) | −0.07832 (18) | 0.0958 (11) | |
C4 | 0.2261 (4) | 0.08673 (19) | 0.06655 (19) | 0.0452 (8) | |
H4A | 0.2893 | 0.0789 | 0.0208 | 0.080* | |
C5 | 0.3225 (4) | 0.1320 (2) | 0.1287 (2) | 0.0500 (8) | |
C5' | 0.4858 (5) | 0.1071 (3) | 0.1386 (3) | 0.0666 (11) | |
C5" | 0.6881 (6) | 0.0167 (4) | 0.0925 (4) | 0.0989 (18) | |
H5"A | 0.7063 | −0.0048 | 0.1444 | 0.080* | |
H5"B | 0.7597 | 0.0607 | 0.0826 | 0.080* | |
C5'" | 0.7070 (9) | −0.0516 (4) | 0.0372 (6) | 0.150 (3) | |
H5'A | 0.8093 | −0.0735 | 0.0395 | 0.080* | |
H5'B | 0.6346 | −0.0950 | 0.0477 | 0.080* | |
H5'C | 0.6882 | −0.0292 | −0.0144 | 0.080* | |
O5' | 0.5794 (4) | 0.1333 (4) | 0.1862 (3) | 0.1304 (18) | |
O5" | 0.5289 (3) | 0.04798 (19) | 0.0863 (2) | 0.0781 (9) | |
C6 | 0.2593 (5) | 0.1931 (2) | 0.1733 (2) | 0.0553 (9) | |
C6' | 0.3350 (7) | 0.2394 (3) | 0.2407 (3) | 0.0838 (14) | |
H6'A | 0.4339 | 0.2199 | 0.2473 | 0.080* | 0.50 |
H6'B | 0.3359 | 0.2991 | 0.2299 | 0.080* | 0.50 |
H6'C | 0.2742 | 0.2318 | 0.2884 | 0.080* | 0.50 |
H6'D | 0.2558 | 0.2751 | 0.2659 | 0.080* | 0.50 |
H6'E | 0.3795 | 0.2016 | 0.2755 | 0.080* | 0.50 |
H6'F | 0.4343 | 0.2601 | 0.2318 | 0.080* | 0.50 |
C7 | 0.1772 (4) | −0.00111 (19) | 0.09624 (19) | 0.0435 (7) | |
C8 | 0.0944 (5) | −0.0109 (2) | 0.1662 (2) | 0.0494 (8) | |
H8A | 0.0647 | 0.0370 | 0.1961 | 0.080* | |
C9 | 0.0545 (5) | −0.0904 (2) | 0.1927 (2) | 0.0523 (9) | |
C10 | 0.0975 (4) | −0.16046 (19) | 0.1482 (2) | 0.0477 (8) | |
C11 | 0.1787 (4) | −0.1505 (2) | 0.0778 (2) | 0.0512 (8) | |
C12 | 0.2196 (5) | −0.0706 (2) | 0.0525 (2) | 0.0519 (9) | |
H12A | 0.2757 | −0.0636 | 0.0042 | 0.080* | |
C13 | −0.0673 (8) | −0.0401 (3) | 0.3117 (3) | 0.097 (2) | |
H13A | −0.1204 | −0.0602 | 0.3575 | 0.080* | |
H13B | 0.0233 | −0.0108 | 0.3279 | 0.080* | |
H13C | −0.1332 | −0.0034 | 0.2828 | 0.080* | |
C14 | 0.1761 (8) | −0.2929 (3) | 0.1968 (4) | 0.0940 (17) | |
H14A | 0.1393 | −0.3454 | 0.2153 | 0.080* | |
H14B | 0.2408 | −0.3012 | 0.1517 | 0.080* | |
H14C | 0.2338 | −0.2663 | 0.2379 | 0.080* | |
C15 | 0.3164 (10) | −0.2180 (3) | −0.0280 (4) | 0.124 (3) | |
H15A | 0.3296 | −0.2719 | −0.0507 | 0.080* | |
H15B | 0.2736 | −0.1813 | −0.0668 | 0.080* | |
H15C | 0.4141 | −0.1971 | −0.0110 | 0.080* | |
O9 | −0.0234 (5) | −0.10739 (17) | 0.26251 (17) | 0.0781 (10) | |
O10 | 0.0533 (3) | −0.23849 (14) | 0.17638 (17) | 0.0630 (8) | |
O11 | 0.2118 (4) | −0.22208 (15) | 0.03702 (17) | 0.0723 (9) | |
C3"B | 0.111 (3) | 0.0802 (12) | −0.2168 (10) | 0.184 (8)* | 0.50 |
H3"D | 0.0846 | 0.0691 | −0.2707 | 0.080* | 0.50 |
H3"E | 0.1005 | 0.1383 | −0.2065 | 0.080* | 0.50 |
H3"F | 0.2154 | 0.0637 | −0.2074 | 0.080* | 0.50 |
C3"A | −0.003 (3) | −0.0481 (6) | −0.1502 (12) | 0.181 (8)* | 0.50 |
H3"A | −0.0426 | −0.0592 | −0.2020 | 0.080* | 0.50 |
H3"B | 0.0778 | −0.0864 | −0.1383 | 0.080* | 0.50 |
H3"C | −0.0839 | −0.0540 | −0.1121 | 0.080* | 0.50 |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.075 (2) | 0.0504 (16) | 0.0582 (17) | 0.0106 (17) | −0.0003 (18) | −0.0082 (14) |
C2 | 0.068 (2) | 0.0448 (16) | 0.0570 (19) | 0.0055 (18) | −0.002 (2) | 0.0069 (16) |
C2' | 0.097 (4) | 0.067 (3) | 0.091 (3) | 0.036 (3) | −0.021 (3) | 0.000 (2) |
C3 | 0.060 (2) | 0.0432 (16) | 0.0478 (17) | −0.0002 (17) | −0.0025 (17) | 0.0104 (14) |
C3' | 0.075 (3) | 0.060 (2) | 0.058 (2) | 0.005 (2) | −0.012 (2) | 0.0084 (18) |
C3" | 0.137 (6) | 0.153 (6) | 0.082 (3) | 0.017 (5) | −0.036 (4) | −0.016 (4) |
O3' | 0.101 (3) | 0.125 (3) | 0.087 (2) | 0.029 (3) | −0.036 (2) | −0.006 (2) |
O3" | 0.109 (3) | 0.116 (3) | 0.0619 (16) | 0.023 (3) | −0.0265 (19) | −0.0273 (18) |
C4 | 0.0506 (19) | 0.0398 (15) | 0.0451 (16) | −0.0037 (15) | 0.0046 (16) | 0.0040 (13) |
C5 | 0.054 (2) | 0.0451 (16) | 0.0510 (18) | −0.0099 (17) | 0.0001 (17) | 0.0045 (15) |
C5' | 0.052 (2) | 0.075 (3) | 0.073 (2) | −0.009 (2) | 0.002 (2) | −0.011 (2) |
C5" | 0.054 (3) | 0.116 (4) | 0.127 (5) | 0.015 (3) | 0.004 (3) | −0.007 (4) |
C5'" | 0.087 (4) | 0.104 (5) | 0.258 (10) | 0.034 (4) | −0.022 (6) | −0.026 (6) |
O5' | 0.068 (2) | 0.182 (4) | 0.142 (3) | 0.010 (3) | −0.037 (2) | −0.079 (3) |
O5" | 0.0499 (15) | 0.0785 (18) | 0.106 (2) | 0.0039 (15) | −0.0024 (18) | −0.0224 (19) |
C6 | 0.069 (2) | 0.0448 (16) | 0.0523 (18) | −0.0052 (18) | 0.001 (2) | −0.0020 (16) |
C6' | 0.087 (3) | 0.078 (3) | 0.086 (3) | −0.005 (3) | −0.009 (3) | −0.027 (3) |
C7 | 0.0452 (17) | 0.0406 (15) | 0.0447 (16) | −0.0012 (15) | −0.0049 (15) | 0.0045 (14) |
C8 | 0.058 (2) | 0.0366 (14) | 0.0531 (18) | 0.0016 (16) | 0.0090 (18) | 0.0033 (14) |
C9 | 0.059 (2) | 0.0457 (17) | 0.0527 (18) | 0.0023 (16) | 0.0101 (18) | 0.0074 (15) |
C10 | 0.0528 (19) | 0.0347 (14) | 0.0556 (18) | −0.0019 (15) | −0.0019 (18) | 0.0059 (14) |
C11 | 0.057 (2) | 0.0413 (16) | 0.0556 (19) | 0.0010 (17) | −0.0008 (19) | −0.0019 (15) |
C12 | 0.058 (2) | 0.0441 (16) | 0.0535 (18) | −0.0024 (17) | 0.0073 (18) | −0.0011 (15) |
C13 | 0.143 (5) | 0.065 (2) | 0.084 (3) | −0.008 (3) | 0.058 (4) | 0.004 (2) |
C14 | 0.115 (4) | 0.057 (2) | 0.110 (4) | 0.024 (3) | 0.003 (4) | 0.024 (3) |
C15 | 0.165 (7) | 0.063 (3) | 0.144 (5) | −0.007 (4) | 0.070 (5) | −0.031 (3) |
O9 | 0.113 (3) | 0.0516 (14) | 0.0700 (16) | −0.0042 (18) | 0.0398 (18) | 0.0077 (13) |
O10 | 0.0708 (18) | 0.0418 (12) | 0.0763 (17) | −0.0025 (13) | −0.0022 (16) | 0.0098 (12) |
O11 | 0.095 (2) | 0.0445 (13) | 0.0771 (17) | −0.0031 (16) | 0.0222 (18) | −0.0144 (13) |
Geometric parameters (Å, º) top
N1—C2 | 1.386 (5) | C5'—O5" | 1.358 (5) |
N1—C6 | 1.412 (6) | C5"—C5'" | 1.457 (10) |
C2—C3 | 1.368 (5) | C5"—O5" | 1.480 (6) |
C2—C2' | 1.528 (6) | C6—C6' | 1.516 (6) |
C3—C3' | 1.494 (6) | C7—C12 | 1.395 (5) |
C3—C4 | 1.544 (5) | C7—C8 | 1.397 (5) |
C3'—O3' | 1.218 (6) | C8—C9 | 1.405 (5) |
C3'—O3" | 1.344 (6) | C9—O9 | 1.391 (4) |
C3"—C3"A | 1.4297 (15) | C9—C10 | 1.412 (5) |
C3"—C3"B | 1.4298 (13) | C10—C11 | 1.396 (5) |
C3"—O3" | 1.448 (7) | C10—O10 | 1.403 (4) |
C4—C5 | 1.534 (5) | C11—O11 | 1.378 (4) |
C4—C7 | 1.566 (4) | C11—C12 | 1.408 (5) |
C5—C6 | 1.359 (5) | C13—O9 | 1.424 (5) |
C5—C5' | 1.488 (6) | C14—O10 | 1.428 (6) |
C5'—O5' | 1.223 (5) | C15—O11 | 1.432 (7) |
| | | |
C2—N1—C6 | 123.3 (3) | C5'"—C5"—O5" | 108.6 (5) |
C3—C2—N1 | 119.1 (4) | C5'—O5"—C5" | 117.0 (4) |
C3—C2—C2' | 127.1 (4) | C5—C6—N1 | 119.8 (3) |
N1—C2—C2' | 113.8 (3) | C5—C6—C6' | 126.9 (4) |
C2—C3—C3' | 121.1 (4) | N1—C6—C6' | 113.3 (4) |
C2—C3—C4 | 121.0 (3) | C12—C7—C8 | 119.8 (3) |
C3'—C3—C4 | 117.9 (3) | C12—C7—C4 | 119.2 (3) |
O3'—C3'—O3" | 121.6 (4) | C8—C7—C4 | 121.1 (3) |
O3'—C3'—C3 | 127.4 (4) | C7—C8—C9 | 120.2 (3) |
O3"—C3'—C3 | 110.9 (4) | O9—C9—C8 | 125.0 (3) |
C3"A—C3"—C3"B | 127.4 (14) | O9—C9—C10 | 115.1 (3) |
C3"A—C3"—O3" | 113.1 (10) | C8—C9—C10 | 119.8 (3) |
C3"B—C3"—O3" | 110.0 (11) | C11—C10—O10 | 122.2 (3) |
C3'—O3"—C3" | 118.3 (5) | C11—C10—C9 | 119.9 (3) |
C5—C4—C3 | 111.7 (3) | O10—C10—C9 | 117.9 (3) |
C5—C4—C7 | 111.2 (3) | O11—C11—C10 | 116.0 (3) |
C3—C4—C7 | 110.5 (3) | O11—C11—C12 | 124.4 (3) |
C6—C5—C5' | 121.4 (4) | C10—C11—C12 | 119.6 (3) |
C6—C5—C4 | 120.4 (3) | C7—C12—C11 | 120.7 (3) |
C5'—C5—C4 | 118.1 (3) | C9—O9—C13 | 118.6 (3) |
O5'—C5'—O5" | 119.4 (4) | C10—O10—C14 | 115.5 (3) |
O5'—C5'—C5 | 128.2 (4) | C11—O11—C15 | 118.7 (3) |
O5"—C5'—C5 | 112.5 (4) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O10i | 0.90 | 2.42 | 3.219 (5) | 149 |
N1—H1A···O9i | 0.90 | 2.42 | 3.189 (5) | 143 |
Symmetry code: (i) −x, y+1/2, −z+1/2. |
Experimental details
| (I) | (II) | (III) |
Crystal data |
Chemical formula | C21H27NO6 | C21H27NO6 | C22H29NO7 |
Mr | 389.4 | 389.4 | 419.46 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, P21/n | Orthorhombic, P212121 |
Temperature (K) | 301 | 301 | 301 |
a, b, c (Å) | 8.268 (4), 17.802 (7), 14.707 (8) | 8.462 (6), 7.637 (6), 33.44 (2) | 8.714 (8), 16.167 (14), 16.948 (14) |
α, β, γ (°) | 90, 93.32 (2), 90 | 90, 94.48 (2), 90 | 90, 90, 90 |
V (Å3) | 2161 (2) | 2154 (3) | 2388 (5) |
Z | 4 | 4 | 4 |
Radiation type | Mo Kα | Mo Kα | Mo Kα |
µ (mm−1) | 0.09 | 0.09 | 0.09 |
Crystal size (mm) | 0.1 × 0.1 × 0.1 | 0.1 × 0.1 × 0.1 | 0.3 × 0.2 × 0.2 |
|
Data collection |
Diffractometer | Syntex P4 4-circle- diffractometer | Syntex P4 4-circle- diffractometer | Syntex P4 4-circle- diffractometer |
Absorption correction | – | – | – |
No. of measured, independent and observed reflections | 7927, 6302, 2411 [I > 2σ(I)] | 8355, 6261, 2644 [I > 2σ(I)] | 4844, 4634, 2616 [I<2σ(I)] |
Rint | 0.059 | 0.062 | 0.041 |
(sin θ/λ)max (Å−1) | 0.704 | 0.705 | 0.704 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.071, 0.250, 1.01 | 0.085, 0.263, 1.01 | 0.069, 0.220, 1.00 |
No. of reflections | 6302 | 6261 | 4634 |
No. of parameters | 254 | 253 | 270 |
No. of restraints | 0 | ? | ? |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.19, −0.23 | 0.21, −0.22 | 0.34, −0.28 |
1,4-Dihydropyridine compounds (DHPs) are widely prescribed for treatment of hypertension and heart defibrilation. Their activity is believed to arise from binding with a receptor site located in the alpha1 subunit of the L type voltage gated channels present in skeletal and cardiac muscle (Tanabe et al., 1987).
Early molecular modeling work involving SYBYL (TRIPOS Scientific, 1982) did not permit conformational flexibility of the drug or the receptor site. A static molecule was fitted into a static receptor site. Newer software (TRIPOS Scientific, 1998; Jones et al., 1999) permits rotation about specified bonds of both drug and receptor site groups, however, results using the newer programs do not agree with each other nor do they support the results of docking studies carried out with SYBYL. Thus, one seeks a knowledge of DHP interactions with polar environments as a basis for evaluation of the molecular modeling results. For DHP molecules (see Scheme), structure-activity relationship studies (Triggle et al., 1989) have indicated specific conformational details which correlate with high binding efficiency. (1) The A ring should be in a flattened boat form (the total planarity achieved by making ring A aromatic is detrimental to activity; Rowan & Holt, 1995, 1996a). (2) The B ring should be in a pseudo-axial position relative to the floor of the boat. (3) Rings A and B should display an orthogonal relationship. (4) Electron-withdrawing substituents on the B ring improve activity in the order o>m>>p. (5) Substituents on the B ring should be in the `prow' position and not projecting backwards over the B ring. Furthermore, the conformation of the carbonyl groups of the ester moieties at C3 and C5 of ring A may be either ap or sp relative to the near double bond of the DHP ring (Scheme).
The conformation of a molecule in the crystal structure does not represent apriori the conformation of the molecule in its receptor site. The environment in the crystalline solid is surely different from that of the molecule in its receptor site. However, the process of crystallization, of maximizing hydrogen bonding, dipole-dipole and van der Waals type interactions within the solid must mimic the behavior of a molecule approaching its docking site. Both are processes of molecular recognition. Thus it is worthwhile to examine patterns of molecular interaction in the crystal as a guide to what to expect of the docked molecule. Particularly useful to this end are examinations of series of structures containing similar B ring substituents because they offer multiple observations of the molecule adapting to its environment. We have synthesized three DHP molecules with multiple methoxy groups substituted on the B ring: (I), (II) and (III). \sch
DHP molecules with methoxy substituents on the B ring are not unknown in the literature. For example, the synthesis of (II) has been reported (Shirodkar & Varadarajan, 1996: Ohsumi et al., 1995). However, the solid-state structures of (I), (II) and (III) are unreported. Previous work has shown that esterification groups should be small (Rowan & Holt, 1996b, 1997: Rowan, 1996) for optimum activity, thus we have synthesized molecules with ethoxycarbonyl groups at C3 and C5.
Compounds (I), (II) and (III) crystallize with the A rings in flattened boat form. The sum of the absolute values of the six successive torsional angles of the A ring may be used to quantify the flatness of these rings, the total being zero if the ring is totally flat and 240° if the six-membered ring is in classic boat form. The sums of the absolute values of the torsion angles for the A ring in (I), (II) and (II) are 91.0, 102.5 and 76.5°, respectively. Thus all three structures display significant flattening of the boat conformation of the A ring.
All three structures show near orthogonality between the B ring and the base of the flattened boat. The atoms C7—C12 of ring B subtend angles of 88.3 (I), 89.1 (II) or 87.3° (III) with the atoms, C2, C3, C5 and C6 of the base of the boat conformation of the A ring.
The three structures show near coplanarity of the carbonyl C═O bonds with the conjugated double bond of the DHP ring. The torsion angles, C6—C5—C5'-O5' and C2—C3—C3'-O3' are −0.2 (4) and −176.2 (3)° for (I), −168.1 (3) and 1.6 (5)° for (II), 2.6 (8) and −15.5 (7)° for (III). These torsional angles reflect conformations at C5 and C3, respectively, of sp, ap for (I), ap, sp for (II) and sp, sp for the molecules of (III).
We have previously noted that carbonyl groups which are not involved in hydrogen bonding exist in sp conformation (Caignan & Holt, 1999; Caignan et al., 1999) whereas the molecule responds to a hydrogen-bonding opportunity by rotating about the C3—C3' or C5—C5' bond involved to present the carbonyl group in ap conformation. We have observed as a general rule that carbonyl groups not involved in hydrogen bonding crystallize in sp conformation whereas those which do serve as hydrogen-bond acceptors are seen in ap conformation. Thus in (I) the carbonyl group at C3 is seen in ap conformation, and is hydrogen bonded to the hydrogen atom of the amino group of an adjacent molecule [N1···O3' 2.910 (3) Å, H1A···O3' (x, 1/2 − y, −1/2 + z) 1.910 Å, N—H1A—O3' 163.4°]. In (II), the carbonyl group C5'-O5' is seen in ap conformation [N1···O5' 3.048 (4) Å, H1A···O5' (x, −1 + y, z) 2.153 Å, N—H1A—O5' 172.6°]. (III) displays sp, sp orientation and neither carbonyl oxygen atom serves as an acceptor in a hydrogen bond. Instead H1A is involved in a bifurcated hydrogen bond with the methoxy oxygen atoms of the para- and meta-substituted methoxy groups of a neighboring molecule [N1···O9 3.189 (5), H1A···O9 2.427 Å (-x, 1/2 + y, 1/2 − z, N1—H1A—O9 142.6) and N1···O10 3.219 (5) Å, H1A···O10 2.415 Å (-x, 1/2 + y, 1/2 − z, N1—H1A—O10 148.9)]. Our generalizations, thus, hold true for the structures (I), (II) and (III) as a group. Electron pairs of the substituents on the aromatic B rings are involved in hydrogen bonding only for (III) in the crystal. Ether oxygen atoms of the ester groups have not been observed to be involved.
The orientation of substituents on the B ring is of interest. For (I), the ortho methoxy substituent is in the 'prow' position, directed away from the A ring. The meta substituent is thus over the A ring. In (II), the meta methoxy substituent is back over the A ring. In (III), the hydrogen-bonded meta substituent is back over the A ring, whereas the non-hydrogen-bonded substituent is in the `prow' position. These observations suggest that ortho substituents on the B ring prefer a `prow' position for spatial reasons whereas the meta substituents have no preference. The observation of hydrogen bonding to that methoxy oxygen atom (and simultaneously to its para neighbor) in (III) is unexpected and at variance with the expectation that DHP molecules should dock with substituents involved in hydrogen bonding on the `prow' side of the molecule for maximum hydrogen bonding with the receptor site.