Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104000332/fg1724sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104000332/fg1724Isup2.hkl |
CCDC reference: 235343
To a round-bottom flask fitted with a reflux condenser was added alanine (1.0 g, 0.011 mol), acetic anhydride (6.24 ml, 0.066 mol), and pyridine (4.53 ml, 0.056 mol). After refluxing for 6 h, the solution was evaporated in vacuo to constant volume. The residue was dissolved in diethyl ether (50 ml) and extracted three times with sodium bicarbonate (10 ml, 10%). The sample was evaporated in vacuo after washing with distilled water (10 ml) and saturated sodium chloride (10 ml). The crude product was puried by column chromatography on Davisil 62 silica gel by eluting with diethyl ether and then crystallized from ligroine. M.p. 358.5–359.0 K (literature 357–358 K from ether; Bhatt et al., 1976). The H NMR spectrum gave three peaks (δ 1.7, 2.12 and 2.35), which integrated in the ratio 2:1:2. The 13C NMR spectrum gave peaks at 15.292, 15.476, 20.565, 25.726, 125.348, 146.860, 168.748, and 172.245 p.p.m. The infrared spectrum showed carbonyl peaks at 1715 cm−1 (amide) and 1754 cm−1 (ester).
Methyl H atoms were located from an electron-density difference map. Positional and displacement parameters for the H atoms were initially refined, but only displacement parameters were refined during the final cycles of refinement. The C—H distances so obtained are in the range 0.96–0.99 Å.
Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and Scalepak (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1976) and PLATON (Spek, 2002); software used to prepare material for publication: SHELXL97.
C10H15NO4 | F(000) = 456 |
Mr = 213.23 | Dx = 1.315 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2533 reflections |
a = 7.6817 (4) Å | θ = 2.9–27.5° |
b = 7.8385 (3) Å | µ = 0.10 mm−1 |
c = 18.0466 (9) Å | T = 100 K |
β = 97.708 (2)° | Irregular, colorless |
V = 1076.82 (9) Å3 | 0.30 × 0.30 × 0.25 mm |
Z = 4 |
KappaCCD diffractometer | 1859 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.040 |
Graphite monochromator | θmax = 27.5°, θmin = 3.1° |
CCD scans | h = 0→9 |
2629 measured reflections | k = 0→10 |
2462 independent reflections | l = −23→23 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Only H-atom displacement parameters refined |
R[F2 > 2σ(F2)] = 0.042 | w = 1/[σ2(Fo2) + (0.0324P)2 + 0.488P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.099 | (Δ/σ)max < 0.001 |
S = 1.03 | Δρmax = 0.37 e Å−3 |
2462 reflections | Δρmin = −0.18 e Å−3 |
152 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.015 (3) |
Primary atom site location: structure-invariant direct methods |
C10H15NO4 | V = 1076.82 (9) Å3 |
Mr = 213.23 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 7.6817 (4) Å | µ = 0.10 mm−1 |
b = 7.8385 (3) Å | T = 100 K |
c = 18.0466 (9) Å | 0.30 × 0.30 × 0.25 mm |
β = 97.708 (2)° |
KappaCCD diffractometer | 1859 reflections with I > 2σ(I) |
2629 measured reflections | Rint = 0.040 |
2462 independent reflections |
R[F2 > 2σ(F2)] = 0.042 | 0 restraints |
wR(F2) = 0.099 | Only H-atom displacement parameters refined |
S = 1.03 | Δρmax = 0.37 e Å−3 |
2462 reflections | Δρmin = −0.18 e Å−3 |
152 parameters |
Experimental. A crystal of dimensions 0.25 x 0.30 x 0.30 mm was glued to a glass fiber and mounted on a Nonius KappaCCD diffractometer. Intensity data collection at room gave a structure in which not all of the H atoms were found on the electron density difference map, so a 100 K structure was pursued. |
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. Mean plane data from maXus MEAN PLANE# 1 —————————————————————— Plane atoms xi yi zi w e.s.d. —————————————————————— O(1) 1.6171 0.3766 − 0.0123 1190960.5 0.0009 C(2) −0.7201 0.2774 − 0.0263 526265.6 0.0014 N(1) −1.9503 − 0.5166 − 0.0183 819712.2 0.0011 C(10) 0.6341 − 1.8502 0.0689 471895.4 0.0015 C(3) −0.9067 1.7653 0.0606 507132.1 0.0014 C(1) 0.4187 − 0.3810 − 0.0391 507132.1 0.0014 —————————————————————— Non-plane atoms xi yi zi w e.s.d. —————————————————————— O(3) −3.5560 − 1.5439 − 1.3018 902049.3 0.0011 O(4) −1.8335 − 0.4656 2.2376 946546.0 0.0010 O(2) 1.9218 − 0.1093 − 2.1940 946546.0 0.0010 C(4) 2.3468 0.3556 − 1.1691 507132.1 0.0014 C(6) −2.5383 − 0.8935 − 1.2476 507132.1 0.0014 C(5) 3.6941 0.9506 − 0.9623 434685.3 0.0015 C(7) −1.8290 − 0.4201 − 2.4851 407229.1 0.0016 C(8) −2.4716 − 0.8123 1.2600 507132.1 0.0014 H(7 A) −2.3247 − 0.7453 − 3.2697 1000.0 0.0000 H(5 A) 4.3425 0.2395 − 0.9931 1000.0 0.0000 H(5B) 3.7754 1.3746 − 0.1134 1000.0 0.0000 H(5 C) 3.8968 1.5692 − 1.6811 1000.0 0.0000 H(7B) −0.9205 − 0.7565 − 2.5272 1000.0 0.0000 H(9 A) −3.7508 − 2.3895 0.9628 1000.0 0.0000 H(9B) −4.4712 − 1.0438 0.8978 1000.0 0.0000 H(10 A) 1.3479 − 2.1406 − 0.5159 1000.0 0.0000 H(10B) −0.1592 − 2.3643 − 0.1161 1000.0 0.0000 H(12) 0.9476 − 2.0676 0.9767 1000.0 0.0000 H(7 C) −1.7774 0.5390 − 2.5091 1000.0 0.0000 C(9) −3.7788 − 1.5228 1.3938 448585.7 0.0015 H(9 C) −3.9602 − 1.6049 2.3274 1000.0 0.0000 H(3 A) −1.4667 2.1109 − 0.6854 1000.0 0.0000 H(3B) −1.3531 1.9805 0.9118 1000.0 0.0000 H(3 C) −0.0627 2.2208 0.0361 1000.0 0.0000 C(11) −5.5662 − 2.0432 − 3.8266 1000.0 0.0000 C(12) 0.7854 − 3.4451 0.5486 1000.0 0.0000 —————————————————————— Chi squared = 5710.9463 Degrees of freedom = 3 —————————————————————— w is the refinement weight of each atom xi, yi & zi are the coordinates with respect to the inertial axes zi represents the atomic displacement from the mean plane with an e.s.d. in the column so labelled —————————————————————— MEAN PLANE# 2 —————————————————————— Plane atoms xi yi zi w e.s.d. —————————————————————— O(3) −1.6219 − 0.9338 − 0.0402 902049.3 0.0011 O(4) 2.2305 0.4137 − 0.0259 946546.0 0.0011 N(1) −0.0101 0.7035 0.0074 819712.2 0.0011 C(6) −1.3468 0.2430 − 0.0048 507132.1 0.0014 C(7) −2.4066 1.3073 0.0469 407229.1 0.0016 C(8) 1.1366 − 0.1201 0.0115 507132.1 0.0014 C(9) 0.9957 − 1.6061 0.0717 448585.7 0.0016 —————————————————————— Non-plane atoms xi yi zi w e.s.d. —————————————————————— O(1) 0.6340 4.1641 − 1.0570 1190960.5 0.0009 O(2) −1.5126 4.5773 − 1.6137 946546.0 0.0011 C(2) 0.2510 2.1433 0.0576 526265.6 0.0014 C(4) −0.3931 4.9821 − 1.4407 507132.1 0.0014 C(10) 0.3386 2.1983 − 2.4642 471895.4 0.0015 C(3) 0.4576 2.7188 1.4295 507132.1 0.0014 C(1) 0.3473 2.7758 − 1.0919 507132.1 0.0014 C(5) 0.0771 6.3812 − 1.6232 434685.3 0.0016 H(7 A) −3.2867 0.8691 0.0282 1000.0 0.0000 H(5 A) 0.0750 6.5763 − 2.5660 1000.0 0.0000 H(5B) 0.9668 6.5074 − 1.3075 1000.0 0.0000 H(5 C) −0.5359 6.9956 − 1.1908 1000.0 0.0000 H(7B) −2.3421 1.9128 − 0.7078 1000.0 0.0000 H(9 A) 0.4890 − 1.9396 − 0.6832 1000.0 0.0000 H(9B) 0.4499 − 1.8586 0.8419 1000.0 0.0000 H(10 A) −0.1558 2.7623 − 3.0752 1000.0 0.0000 H(10B) −0.0169 1.3037 − 2.4968 1000.0 0.0000 H(12) 1.2572 2.1870 − 2.8186 1000.0 0.0000 H(7 C) −2.3257 1.8380 0.8437 1000.0 0.0000 H(9 C) 1.8772 − 1.9720 0.0872 1000.0 0.0000 H(3 A) −0.3270 2.5568 2.0193 1000.0 0.0000 H(3B) 1.2473 2.2939 1.8369 1000.0 0.0000 H(3 C) 0.6091 3.6651 1.3875 1000.0 0.0000 C(11) −4.4630 − 2.4190 0.5823 1000.0 0.0000 C(12) 0.6728 1.4352 − 3.9142 1000.0 0.0000 —————————————————————— Chi squared = 5143.3042 Degrees of freedom = 4 —————————————————————— w is the refinement weight of each atom xi, yi & zi are the coordinates with respect to the inertial axes zi represents the atomic displacement from the mean plane with an e.s.d. in the column so labelled —————————————————————— MEAN PLANE# 3 —————————————————————— Plane atoms xi yi zi w e.s.d. —————————————————————— O(1) 1.0730 − 0.3185 − 0.0007 1190960.5 0.0009 O(2) −1.1766 − 0.4854 − 0.0011 946546.0 0.0010 C(4) −0.1911 0.2044 0.0052 507132.1 0.0014 C(5) −0.1548 1.6912 − 0.0018 434685.3 0.0015 —————————————————————— Non-plane atoms xi yi zi w e.s.d. —————————————————————— O(3) 0.5250 − 5.9385 0.4769 902049.3 0.0011 O(4) 3.7790 − 3.5358 − 0.0671 946546.0 0.0010 C(2) 1.5151 − 2.4853 0.7624 526265.6 0.0014 N(1) 1.6245 − 3.9205 0.4944 819712.2 0.0011 C(10) 0.9359 − 2.0936 − 1.6627 471895.4 0.0015 C(6) 0.4918 − 4.7466 0.6775 507132.1 0.0014 C(3) 1.9135 − 2.0500 2.1437 507132.1 0.0014 C(1) 1.1493 − 1.7143 − 0.2388 507132.1 0.0014 C(7) −0.7536 − 4.0539 1.1547 407229.1 0.0016 C(8) 2.9041 − 4.3665 0.0983 507132.1 0.0014 H(7 A) −1.4679 − 4.7246 1.2393 1000.0 0.0000 H(5 A) −0.4482 1.9929 − 0.8677 1000.0 0.0000 H(5B) 0.7239 2.0317 0.1367 1000.0 0.0000 H(5 C) −0.7716 2.0405 0.6598 1000.0 0.0000 H(7B) −1.0410 − 3.3671 0.5335 1000.0 0.0000 H(9 A) 2.5842 − 6.1945 − 0.7784 1000.0 0.0000 H(9B) 2.9184 − 6.3190 0.7072 1000.0 0.0000 H(10 A) 0.1748 − 1.6274 − 2.0360 1000.0 0.0000 H(10B) 0.8232 − 3.0417 − 1.7897 1000.0 0.0000 H(12) 1.7045 − 1.7915 − 2.1989 1000.0 0.0000 H(7 C) −0.6086 − 3.6263 2.0028 1000.0 0.0000 C(9) 3.1656 − 5.8241 − 0.0983 448585.7 0.0015 H(9 C) 4.0846 − 5.9151 − 0.3399 1000.0 0.0000 H(3 A) 1.3743 − 2.5066 2.8440 1000.0 0.0000 H(3B) 2.8624 − 2.2726 2.2858 1000.0 0.0000 H(3 C) 1.8036 − 1.1032 2.2522 1000.0 0.0000 C(11) −1.5874 − 8.2551 1.3909 1000.0 0.0000 C(12) 1.0694 − 2.5388 − 3.2691 1000.0 0.0000 —————————————————————— Chi squared = 16.5827 Degrees of freedom = 1 —————————————————————— w is the refinement weight of each atom xi, yi & zi are the coordinates with respect to the inertial axes zi represents the atomic displacement from the mean plane with an e.s.d. in the column so labelled —————————————————————— ATOM-ATOM VECTORS ———————————————————————- Vector Atom(1) Atom(2) dist x y z ———————————————————————- 4 B-axis Origin 7.8390 0.00000 − 1.00000 0.00000 5 C(3) H(3 C) 0.9593 − 0.75912 − 0.61365 − 0.21718 6 C(10) H(10B) 0.9632 0.62073 0.67901 0.39196 ———————————————————————- x,y & z are the vector direction cosines ———————————————————————- PLANE/VECTOR ANGLES ——————————————– Plane/Vector Plane/Vector Angle e.s.d. ——————————————– 1 2 90.44 3.406 1 3 104.50 2.760 1 4 123.93 2.160 1 5 88.54 2.160 1 6 78.93 2.160 2 3 16.57 3.144 2 4 55.00 2.633 2 5 87.49 2.633 2 6 88.06 2.633 3 4 53.53 1.717 3 5 96.49 1.717 3 6 82.42 1.717 4 5 52.15 0.000 4 6 132.77 0.000 5 6 166.66 0.000 ——————————————– |
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. The structure was solved using SIR97 and refined using SHELX97 within the maXus crystallographic suite. All non-hydrogen atoms were found from the electron density map resulting from the structure solution and were refined with anisotropic displacement parameters. Hydrogen atoms were identified from the electron density difference map and added to the refinement. Positions and displacement parameters for the hydrogen atoms were refined initially, but only displacement parameters were refined during the final cycles of refinement with positional parameters constrained to a riding model. A group of weak (< 0.40 e−/Å3) electron density difference map peaks were found that mimic a mirror image arrangement of the central atoms and suggest minor disorder of the molecule. Refinement of the site occupation factor of the minor component with other parameters fixed gave a value less than 0.02. Refinement of positional parameters of a fixed fragment of the minor component gave a chemically unreasonable orientation, and modelling of the minor component was abandoned. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.41989 (12) | 0.95886 (13) | 0.15142 (5) | 0.0221 (3) | |
O2 | 0.56059 (13) | 0.84609 (13) | 0.06096 (6) | 0.0274 (3) | |
O3 | −0.00462 (14) | 0.37613 (14) | 0.07750 (6) | 0.0309 (3) | |
O4 | −0.05511 (13) | 0.78159 (13) | 0.21487 (6) | 0.0270 (3) | |
N1 | 0.09843 (15) | 0.61007 (14) | 0.14665 (7) | 0.0197 (3) | |
C1 | 0.27530 (18) | 0.85038 (18) | 0.12793 (8) | 0.0208 (3) | |
C2 | 0.25082 (18) | 0.71848 (18) | 0.17046 (8) | 0.0203 (3) | |
C3 | 0.35656 (19) | 0.67149 (19) | 0.24374 (8) | 0.0227 (3) | |
C4 | 0.55369 (18) | 0.95238 (18) | 0.10855 (8) | 0.0207 (3) | |
C5 | 0.6817 (2) | 1.0928 (2) | 0.12836 (9) | 0.0266 (4) | |
C6 | 0.11645 (19) | 0.47037 (18) | 0.09871 (8) | 0.0219 (3) | |
C7 | 0.2963 (2) | 0.4448 (2) | 0.07649 (9) | 0.0301 (4) | |
C8 | −0.05649 (18) | 0.65394 (18) | 0.17635 (8) | 0.0211 (3) | |
C9 | −0.21652 (19) | 0.5446 (2) | 0.16092 (9) | 0.0271 (4) | |
C10 | 0.15879 (19) | 0.91383 (19) | 0.06101 (8) | 0.0239 (3) | |
H3A | 0.4550 | 0.7466 | 0.2554 | 0.035 (5)* | |
H3B | 0.4017 | 0.5526 | 0.2433 | 0.033 (5)* | |
H3C | 0.2811 | 0.6810 | 0.2836 | 0.031 (4)* | |
H5A | 0.6691 | 1.1739 | 0.0879 | 0.050 (6)* | |
H5B | 0.6605 | 1.1520 | 0.1724 | 0.042 (5)* | |
H5C | 0.8006 | 1.0485 | 0.1335 | 0.057 (6)* | |
H7A | 0.2924 | 0.3451 | 0.0432 | 0.031 (4)* | |
H7B | 0.3340 | 0.5433 | 0.0503 | 0.048 (5)* | |
H7C | 0.3823 | 0.4265 | 0.1196 | 0.047 (5)* | |
H9A | −0.2557 | 0.5366 | 0.1078 | 0.030 (4)* | |
H9B | −0.1877 | 0.4267 | 0.1754 | 0.030 (4)* | |
H9C | −0.3046 | 0.5942 | 0.1867 | 0.042 (5)* | |
H10A | 0.2268 | 0.9526 | 0.0229 | 0.046 (5)* | |
H10B | 0.0743 | 0.8304 | 0.0399 | 0.047 (5)* | |
H10C | 0.0955 | 1.0158 | 0.0747 | 0.047 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0205 (5) | 0.0219 (5) | 0.0253 (5) | −0.0062 (4) | 0.0078 (4) | −0.0048 (4) |
O2 | 0.0271 (6) | 0.0271 (6) | 0.0294 (6) | −0.0007 (4) | 0.0087 (5) | −0.0071 (5) |
O3 | 0.0276 (6) | 0.0277 (6) | 0.0373 (6) | −0.0073 (5) | 0.0038 (5) | −0.0121 (5) |
O4 | 0.0262 (6) | 0.0229 (5) | 0.0336 (6) | −0.0022 (4) | 0.0109 (5) | −0.0055 (5) |
N1 | 0.0181 (6) | 0.0177 (6) | 0.0240 (6) | −0.0030 (5) | 0.0053 (5) | −0.0019 (5) |
C1 | 0.0199 (7) | 0.0210 (7) | 0.0220 (7) | −0.0012 (6) | 0.0042 (6) | −0.0050 (6) |
C2 | 0.0196 (7) | 0.0196 (7) | 0.0224 (7) | −0.0003 (6) | 0.0054 (6) | −0.0029 (6) |
C3 | 0.0216 (8) | 0.0226 (8) | 0.0235 (7) | −0.0032 (6) | 0.0011 (6) | 0.0014 (6) |
C4 | 0.0190 (7) | 0.0229 (7) | 0.0211 (7) | 0.0001 (6) | 0.0054 (6) | 0.0016 (6) |
C5 | 0.0252 (8) | 0.0259 (8) | 0.0300 (9) | −0.0058 (6) | 0.0085 (7) | −0.0026 (7) |
C6 | 0.0251 (8) | 0.0189 (7) | 0.0217 (7) | −0.0003 (6) | 0.0031 (6) | −0.0009 (6) |
C7 | 0.0281 (8) | 0.0277 (8) | 0.0362 (9) | −0.0017 (7) | 0.0102 (7) | −0.0106 (7) |
C8 | 0.0206 (7) | 0.0198 (7) | 0.0233 (7) | −0.0005 (6) | 0.0042 (6) | 0.0031 (6) |
C9 | 0.0208 (8) | 0.0276 (8) | 0.0335 (9) | −0.0031 (6) | 0.0055 (7) | −0.0023 (7) |
C10 | 0.0247 (8) | 0.0247 (8) | 0.0223 (7) | −0.0014 (6) | 0.0024 (6) | 0.0021 (6) |
O1—C1 | 1.4178 (16) | C3—H3B | 0.99 |
O1—C4 | 1.3679 (17) | C3—H3C | 0.99 |
O2—C4 | 1.2029 (17) | C5—H5A | 0.96 |
O3—C6 | 1.2090 (17) | C5—H5B | 0.95 |
O4—C8 | 1.2178 (17) | C5—H5C | 0.97 |
N1—C2 | 1.4637 (18) | C7—H7A | 0.98 |
N1—C6 | 1.4138 (18) | C7—H7B | 0.97 |
N1—C8 | 1.4117 (18) | C7—H7C | 0.96 |
C1—C2 | 1.316 (2) | C9—H9A | 0.97 |
C1—C10 | 1.489 (2) | C9—H9B | 0.98 |
C2—C3 | 1.502 (2) | C9—H9C | 0.95 |
C4—C5 | 1.487 (2) | C10—H10A | 0.97 |
C6—C7 | 1.503 (2) | C10—H10B | 0.96 |
C8—C9 | 1.494 (2) | C10—H10C | 0.98 |
C3—H3A | 0.96 | ||
C4—O1—C1 | 115.25 (11) | C4—C5—H5A | 108.1 |
C8—N1—C6 | 125.29 (12) | C4—C5—H5B | 112.3 |
C8—N1—C2 | 115.40 (11) | H5A—C5—H5B | 107.4 |
C6—N1—C2 | 119.29 (11) | C4—C5—H5C | 110.0 |
C2—C1—O1 | 117.67 (12) | H5A—C5—H5C | 107.9 |
C2—C1—C10 | 128.17 (13) | H5B—C5—H5C | 111.0 |
O1—C1—C10 | 113.81 (12) | C6—C7—H7A | 108.4 |
C1—C2—N1 | 117.14 (12) | C6—C7—H7B | 111.6 |
C1—C2—C3 | 127.11 (13) | H7A—C7—H7B | 108.8 |
N1—C2—C3 | 115.65 (12) | C6—C7—H7C | 111.1 |
O2—C4—O1 | 122.55 (13) | H7A—C7—H7C | 109.7 |
O2—C4—C5 | 126.39 (13) | H7B—C7—H7C | 107.2 |
O1—C4—C5 | 111.06 (12) | C8—C9—H9A | 111.1 |
O3—C6—N1 | 122.19 (13) | C8—C9—H9B | 110.0 |
O3—C6—C7 | 121.98 (13) | H9A—C9—H9B | 103.5 |
N1—C6—C7 | 115.83 (12) | C8—C9—H9C | 107.1 |
O4—C8—N1 | 118.28 (13) | H9A—C9—H9C | 111.3 |
O4—C8—C9 | 121.46 (13) | H9B—C9—H9C | 113.8 |
N1—C8—C9 | 120.26 (13) | C1—C10—H10A | 111.0 |
C2—C3—H3A | 111.1 | C1—C10—H10B | 113.2 |
C2—C3—H3B | 111.8 | H10A—C10—H10B | 109.3 |
H3A—C3—H3B | 108.1 | C1—C10—H10C | 109.3 |
C2—C3—H3C | 108.8 | H10A—C10—H10C | 104.8 |
H3A—C3—H3C | 108.5 | H10B—C10—H10C | 108.8 |
H3B—C3—H3C | 108.5 |
Experimental details
Crystal data | |
Chemical formula | C10H15NO4 |
Mr | 213.23 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 100 |
a, b, c (Å) | 7.6817 (4), 7.8385 (3), 18.0466 (9) |
β (°) | 97.708 (2) |
V (Å3) | 1076.82 (9) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.30 × 0.30 × 0.25 |
Data collection | |
Diffractometer | KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2629, 2462, 1859 |
Rint | 0.040 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.099, 1.03 |
No. of reflections | 2462 |
No. of parameters | 152 |
H-atom treatment | Only H-atom displacement parameters refined |
Δρmax, Δρmin (e Å−3) | 0.37, −0.18 |
Computer programs: KappaCCD Server Software (Nonius, 1997), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO and Scalepak (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP (Johnson, 1976) and PLATON (Spek, 2002), SHELXL97.
O1—C1 | 1.4178 (16) | N1—C8 | 1.4117 (18) |
O1—C4 | 1.3679 (17) | C1—C2 | 1.316 (2) |
O2—C4 | 1.2029 (17) | C1—C10 | 1.489 (2) |
O3—C6 | 1.2090 (17) | C2—C3 | 1.502 (2) |
O4—C8 | 1.2178 (17) | C4—C5 | 1.487 (2) |
N1—C2 | 1.4637 (18) | C6—C7 | 1.503 (2) |
N1—C6 | 1.4138 (18) | C8—C9 | 1.494 (2) |
C2—C1—O1 | 117.67 (12) | C1—C2—N1 | 117.14 (12) |
C2—C1—C10 | 128.17 (13) | C1—C2—C3 | 127.11 (13) |
O1—C1—C10 | 113.81 (12) | N1—C2—C3 | 115.65 (12) |
The reaction of the α-amino acid alanine with acetic anhydride and pyridine gives (1E)-2-(diacetylamino)-1-methylprop-1-enyl acetate, (I). The Dakin–West reaction (Dakin & West, 1928) would normally be expected to give N-(1-methyl-2-oxopropyl)acetamide, (II), but further reaction with acetic anhydride and pyridine gives (I), to which was assigned the E configuration (Zav'yalov & Ezhova, 1977), on the basis of the observation that 2-(diacetylamino)cyclohexyl-1-enyl acetate, (III), yields 2-methyl-4,5,6,7-tetrahydrobenzoxazole, (IV) when partially hydrolyzed (Bhatt et al., 1976). Lack of oxazole formation when (I) is partially hydrolyzed was taken as evidence for the E configuration of (I). Tian-Han & Xiao-Tin (1986) tentatively assigned the E configuration to (I) using the results of a difference nuclear Overhauser experiment.
The crystal structure firmly establishes the stereochemistry of the molecule as E, as shown in Fig. 1. Selected molecular dimensions are given in Table 1. The C1—C2 ethene bond length corresponds to the expected value for a C=C double bond, and bond lengths to substituent atoms of the ethene group correspond to expected values for single bonds involving these elements. Thus no resonance is found between the amide and acetate substituents and the central ethene group. This result is not suprizing, since the planar acetate and amide substituents are oriented approximately perpendicular to the ethene plane (and approximately coplanar to one another), with angles of 90 (3) and 105 (3)° between the ethene core and the amide and acetate mean planes, respectively. The di(acetyl)amine and acetate substitutents exhibit essentially planar geometries, as expected.
The H atoms of each methyl-group substituent to the ethene double bond are oriented such that a C—H bond vector is almost coplanar with the ethene plane (N1—C2—C3—H3A = 179° and O1—C1—C10—H10B = 169°), which implies that hyperconjugation is not important in stabilizing the double bond in this molecule.
The a and b unit-cell parameters are almost equal, which, together with a β angle close to 90°, suggests a quasi-tetragonal extended structure. This, indeed, appears to be the case, as shown in Fig. 2. The structure can be envisioned as a stacking of square-packed layers of molecules along the c axis. Within a given layer, the molecules are all translationally equivalent. The layers are then paired with an inversion-related neighboring layer, in which the central ethene planes are parallel to one another. These bilayer assemblies are then stacked together such that neighboring bilayers are related to one another by a twofold screw axis or n-glide plane and the central ethene planes are at an angle of 68° with respect to one another.