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The title compound, C20H19NO3, has a strongly pyramidal aziridine N atom, not conjugated with the adjacent C=O bond.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803005981/cv6177sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803005981/cv6177Isup2.hkl
Contains datablock I

CCDC reference: 209967

Key indicators

  • Single-crystal X-ray study
  • T = 150 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.042
  • wR factor = 0.097
  • Data-to-parameter ratio = 13.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
ABSTM_02 Alert C The ratio of expected to reported Tmax/Tmin(RR') is < 0.90 Tmin and Tmax reported: 0.757 1.000 Tmin' and Tmax expected: 0.966 0.983 RR' = 0.771 Please check that your absorption correction is appropriate.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The title compound, (I), was prepared in the course of our studies of thermal earrangements of vinyl epoxydes and vinyl aziridines (Aldous et al., 1999), by a one-pot modification of literature methods for the aziridine formation and subsequent protection, e.g. described for the parent NH aziridine by Wipf & Fritch (1994) and Coldham et al. (1995).

The ethylpropenoate chain, C2'/C3/C2/C1/O1/O2/C4/C5, is planar with a mean atomic deviation of 0.04 Å. It forms a dihedral angle of 74.4 (1)° with the aziridine ring plane. With respect to the latter, the phenyl substituent at C3' is trans and the benzoate substituent at N1' is cis to the ethylpropenoate group.

The N1' atom is strongly pyramidal, with the sum of valent angles of 308.2 (3)° (cf. 360° for the ideally planar and 328.5° for tetrahedral geometry). The out-of-(aziridine)plane tilt of the N1'—C6 bond (Ohwada et al., 1998) is 50.3 (1)°. In this respect, (I) is similar to other acylaziridine derivatives (Zacharis & Trefonas, 1968; Gopalakrishna, 1972; Brzozowski et al., 1988; Ferraris et al., 1998), but different from acyclic tertiary amides, where the nitrogen atom is always planar-trigonal and its lone electron pair is conjugated with the carbonyl group. In (I), the `torsion angle' (around the N1'—C6 bond) between the directions of the N1' lone pair and the C6 pπ orbital does not exceed 16°, i.e. is compatible with conjugation. Nevertheless, the N1'—C6 bond distance of 1.395 (2) Å in (I), while comparable with the range of 1.383–1.388 Å in previously reported acylaziridines (see above), is considerably longer than in acyclic amides with two sp3 C atoms bonded to the N atom [average 1.346 (10) Å (Chakrabarti & Dunitz, 1982) or 1.352 (10) Å (Allen et al., 1987)]. The amides, in which the N atom is incorporated into a larger cycle, e.g. a proline ring, show even shorter C(O)—N bonds, averaging 1.335 (9) Å (Chakrabarti & Dunitz, 1982).

The geometry of the aziridine ring is similar to that previously observed (e.g. Ohwada et al., 1998). It agrees also with the results of a microwave study of the free aziridine, C2H5N, in the gas phase by Turner et al. (1955).

Experimental top

The azide alcohol PhCH(OH)CH(N3)CCCO2Et (2.48 g, 9.51 mmol) in DCM (10 ml) was added dropwise to a stirred solution of PPh3 (3.41 mg, 13.1 mmol) at 273 K. Acetic acid (100 µl) in DCM (5 ml) was added under argon. The reaction mixture was warmed to room temperature over 3 h, after 1 h it was cooled to 273 K and triethylamine (4 g, 40 mmol) was added until the pH increased to 8 (measured using universal testing paper). Benzoyl chloride was added (1.4 g, 10 mmol) and the reaction stirred for 18 h while warming to room temperature. The mixture was washed with water (2 × 30 ml) and the aqueous washes back extracted with DCM (30 ml). The combined organic layers were dried (MgSO4), the solvent removed and product purified by flash chromatography (eluting with 10% ethyl acetate in petrol) to yield the title amide, (I), as a colourless crystalline solid (1.32 g, 44%). M.p. 390.7–391.1 K. Analysis calculated for C20H19NO3: C 74.7, H 5.92, N 4.36%; found: C 74.71, H 5.96, N 4.51. IR, ν (cm−1): 1710 and 1654 (CO), 1623 (CC), 1447, 1297, 1257. 1H NMR (d, p.p.m., 400 MHz): 7.96 (2H, d, J= 6.8 Hz, o-Ph), 7.3–7.6 (8H, m, Ph), 6.44 (1H, dd, J = 10 Hz, 16 Hz, H3), 6.14 (1H, d, J = 16 Hz, H2), 4.13 (2H, q, J = 7 Hz, CH2), 3.83 (1H, d, J = 2.4 Hz, H3'), 3.43 (1H, dd, J = 10 Hz, 2.4 Hz, H2'), 1.23 (3H, t, J = 7 Hz, Me). 13C NMR (d, p.p.m., 100 MHz): 176 (C6), 165 (C1), 143 (C2), 135, 133, 132, 130, 129, 128, 128, 126 (Ph), 125 (C3), 60 (C3'), 49 (C2'), 47 (C4), 14 (C5). m/z (CI/NH3): 322 (M+ + H, 33%), 276, 248, 216, 105 (100%).

Refinement top

All H atoms were located in a difference Fourier synthesis and were refined in isotropic approximation. Bond lengths: Csp2—H = 0.97 (1) and 0.98 (1) Å, Csp3—H = 0.96 (2)–1.03 (2) Å and O—H = 0.82 (4) and 0.84 (4) Å.

Computing details top

Data collection: SMART (Bruker, 1995); cell refinement: SMART; data reduction: SAINT (Bruker, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I). Atomic displacement ellipsoids are shown at the 50% probability level and double bonds are shown in black.
Ethyl 3-(1-benzoyl-3-phenylaziridin-2-yl)propenoate top
Crystal data top
C20H19NO3Dx = 1.264 Mg m3
Mr = 321.36Melting point: 391 K K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 10.746 (1) ÅCell parameters from 499 reflections
b = 14.319 (1) Åθ = 10.2–20.9°
c = 10.998 (1) ŵ = 0.09 mm1
β = 93.52 (1)°T = 150 K
V = 1689.1 (2) Å3Block, colourless
Z = 40.4 × 0.3 × 0.2 mm
F(000) = 680
Data collection top
SMART 1K CCD area-detector
diffractometer
3880 independent reflections
Radiation source: fine-focus sealed tube2850 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
Detector resolution: 8 pixels mm-1θmax = 27.5°, θmin = 1.9°
ω scansh = 1313
Absorption correction: multi-scan
[SADABS (Sheldrick, 1998), before correction Rint = 0.054]
k = 1816
Tmin = 0.757, Tmax = 1.000l = 1414
17984 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042All H-atom parameters refined
wR(F2) = 0.097 w = 1/[σ2(Fo2) + (0.0243P)2 + 0.6441P]
where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
3880 reflectionsΔρmax = 0.21 e Å3
294 parametersΔρmin = 0.23 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0099 (9)
Crystal data top
C20H19NO3V = 1689.1 (2) Å3
Mr = 321.36Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.746 (1) ŵ = 0.09 mm1
b = 14.319 (1) ÅT = 150 K
c = 10.998 (1) Å0.4 × 0.3 × 0.2 mm
β = 93.52 (1)°
Data collection top
SMART 1K CCD area-detector
diffractometer
3880 independent reflections
Absorption correction: multi-scan
[SADABS (Sheldrick, 1998), before correction Rint = 0.054]
2850 reflections with I > 2σ(I)
Tmin = 0.757, Tmax = 1.000Rint = 0.046
17984 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.097All H-atom parameters refined
S = 1.09Δρmax = 0.21 e Å3
3880 reflectionsΔρmin = 0.23 e Å3
294 parameters
Special details top

Experimental. The data collection nominally covered full sphere of reciprocal space, by a combination of 5 sets of ω scans; each set at different ϕ and/or 2θ angles and each scan (10 sec exposure) covering 0.3° in ω. Crystal to detector distance 4.58 cm. Crystal decay was monitored by repeating 50 initial frames at the end of data collection and comparing 171 duplicate reflections.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.26714 (9)0.52785 (7)0.30593 (9)0.0305 (3)
O20.30380 (10)0.51798 (8)0.10672 (10)0.0356 (3)
O30.59806 (10)0.19502 (8)0.00123 (9)0.0360 (3)
N1'0.65835 (11)0.26564 (9)0.18177 (10)0.0243 (3)
C10.33476 (13)0.50297 (10)0.21242 (14)0.0266 (3)
C20.44911 (14)0.45394 (11)0.25797 (14)0.0269 (3)
H20.4709 (15)0.4552 (12)0.3455 (15)0.033 (4)*
C2'0.63614 (13)0.36121 (10)0.22540 (13)0.0255 (3)
H2'0.6653 (13)0.3705 (10)0.3093 (14)0.022 (4)*
C30.52116 (14)0.40980 (11)0.18334 (14)0.0272 (3)
H30.4968 (15)0.4099 (12)0.0980 (16)0.036 (5)*
C3'0.73303 (14)0.34125 (11)0.13450 (14)0.0267 (3)
H3'0.7072 (14)0.3610 (11)0.0507 (15)0.029 (4)*
C40.15064 (15)0.57653 (12)0.27355 (16)0.0333 (4)
H410.1715 (15)0.6334 (13)0.2273 (15)0.036 (5)*
H420.0962 (16)0.5345 (13)0.2231 (16)0.042 (5)*
C50.09334 (18)0.59959 (15)0.39096 (19)0.0431 (4)
H510.155 (2)0.6342 (16)0.4438 (19)0.065 (7)*
H520.0702 (17)0.5406 (15)0.4310 (18)0.051 (6)*
H530.0155 (18)0.6379 (13)0.3730 (16)0.046 (5)*
C60.57468 (14)0.21469 (10)0.10577 (13)0.0263 (3)
C110.46185 (13)0.17807 (10)0.16270 (13)0.0262 (3)
C120.44962 (14)0.18199 (11)0.28769 (14)0.0278 (3)
H120.5141 (14)0.2123 (11)0.3371 (14)0.026 (4)*
C130.34666 (15)0.14153 (12)0.33770 (16)0.0355 (4)
H130.3394 (16)0.1443 (13)0.4253 (17)0.044 (5)*
C140.25607 (16)0.09719 (13)0.26331 (19)0.0420 (4)
H140.1852 (18)0.0648 (13)0.3002 (17)0.049 (5)*
C150.26706 (16)0.09426 (13)0.13910 (19)0.0443 (5)
H150.2043 (19)0.0635 (14)0.0841 (18)0.058 (6)*
C160.36941 (15)0.13438 (12)0.08820 (16)0.0370 (4)
H160.3785 (16)0.1329 (13)0.0009 (17)0.046 (5)*
C210.86940 (14)0.34048 (10)0.16850 (13)0.0266 (3)
C220.91746 (15)0.31498 (11)0.28430 (15)0.0313 (4)
H220.8612 (16)0.2982 (12)0.3477 (16)0.040 (5)*
C231.04537 (16)0.30884 (12)0.30946 (17)0.0371 (4)
H231.0780 (16)0.2913 (13)0.3906 (17)0.041 (5)*
C241.12637 (16)0.32799 (12)0.21903 (18)0.0396 (4)
H241.2144 (18)0.3227 (13)0.2361 (17)0.051 (5)*
C251.07945 (16)0.35550 (13)0.10544 (17)0.0406 (4)
H251.1355 (17)0.3725 (13)0.0426 (17)0.049 (5)*
C260.95181 (16)0.36204 (12)0.07984 (15)0.0345 (4)
H260.9160 (16)0.3805 (12)0.0004 (17)0.041 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0266 (5)0.0323 (6)0.0327 (6)0.0057 (4)0.0029 (4)0.0025 (5)
O20.0364 (6)0.0384 (7)0.0320 (6)0.0036 (5)0.0022 (5)0.0064 (5)
O30.0422 (7)0.0432 (7)0.0226 (6)0.0052 (5)0.0025 (5)0.0040 (5)
N1'0.0259 (6)0.0256 (7)0.0218 (6)0.0017 (5)0.0038 (5)0.0003 (5)
C10.0268 (8)0.0214 (8)0.0318 (8)0.0030 (6)0.0036 (6)0.0009 (6)
C20.0269 (8)0.0252 (8)0.0286 (8)0.0028 (6)0.0031 (6)0.0017 (6)
C2'0.0286 (8)0.0251 (8)0.0232 (8)0.0010 (6)0.0046 (6)0.0002 (6)
C30.0291 (8)0.0254 (8)0.0271 (8)0.0002 (6)0.0020 (6)0.0029 (6)
C3'0.0290 (8)0.0288 (8)0.0227 (7)0.0009 (6)0.0054 (6)0.0034 (6)
C40.0271 (8)0.0293 (9)0.0433 (10)0.0061 (7)0.0002 (7)0.0027 (8)
C50.0333 (10)0.0450 (12)0.0523 (12)0.0087 (9)0.0128 (8)0.0057 (9)
C60.0299 (8)0.0262 (8)0.0223 (7)0.0068 (6)0.0016 (6)0.0001 (6)
C110.0261 (7)0.0237 (8)0.0283 (8)0.0042 (6)0.0017 (6)0.0027 (6)
C120.0262 (8)0.0278 (8)0.0292 (8)0.0006 (6)0.0000 (6)0.0010 (6)
C130.0318 (8)0.0368 (10)0.0384 (10)0.0025 (7)0.0069 (7)0.0041 (8)
C140.0275 (9)0.0353 (10)0.0637 (13)0.0015 (7)0.0067 (8)0.0017 (9)
C150.0290 (9)0.0413 (11)0.0613 (12)0.0015 (8)0.0066 (8)0.0152 (9)
C160.0335 (9)0.0398 (10)0.0369 (9)0.0060 (7)0.0045 (7)0.0127 (8)
C210.0280 (8)0.0229 (8)0.0295 (8)0.0003 (6)0.0063 (6)0.0010 (6)
C220.0337 (8)0.0293 (8)0.0311 (8)0.0006 (7)0.0044 (6)0.0013 (7)
C230.0371 (9)0.0296 (9)0.0437 (10)0.0007 (7)0.0049 (8)0.0013 (8)
C240.0276 (9)0.0276 (9)0.0637 (12)0.0030 (7)0.0025 (8)0.0056 (8)
C250.0351 (9)0.0397 (10)0.0485 (11)0.0090 (8)0.0149 (8)0.0054 (8)
C260.0374 (9)0.0356 (9)0.0312 (9)0.0063 (7)0.0092 (7)0.0014 (7)
Geometric parameters (Å, º) top
O1—C11.3432 (18)C11—C121.390 (2)
O1—C41.4577 (18)C11—C161.396 (2)
O2—C11.2087 (18)C12—C131.392 (2)
O3—C61.2246 (17)C12—H120.958 (16)
N1'—C61.3953 (19)C13—C141.386 (2)
N1'—C3'1.4620 (19)C13—H130.972 (18)
N1'—C2'1.4745 (19)C14—C151.379 (3)
C1—C21.476 (2)C14—H140.999 (19)
C2—C31.323 (2)C15—C161.389 (3)
C2—H20.976 (16)C15—H150.98 (2)
C2'—C31.468 (2)C16—H160.971 (19)
C2'—C3'1.514 (2)C21—C261.392 (2)
C2'—H2'0.965 (15)C21—C221.393 (2)
C3—H30.958 (17)C22—C231.388 (2)
C3'—C211.490 (2)C22—H220.980 (17)
C3'—H3'0.988 (16)C23—C241.389 (3)
C4—C51.501 (2)C23—H230.972 (18)
C4—H410.994 (18)C24—C251.376 (3)
C4—H420.986 (18)C24—H240.956 (19)
C5—H510.99 (2)C25—C261.386 (2)
C5—H520.99 (2)C25—H250.974 (19)
C5—H531.009 (19)C26—H260.970 (18)
C6—C111.493 (2)
C1—O1—C4115.89 (12)O3—C6—C11122.10 (14)
C6—N1'—C3'121.45 (12)N1'—C6—C11116.25 (12)
C6—N1'—C2'124.68 (12)C12—C11—C16119.43 (15)
C3'—N1'—C2'62.08 (9)C12—C11—C6121.93 (13)
O2—C1—O1124.01 (14)C16—C11—C6118.55 (14)
O2—C1—C2125.83 (14)C11—C12—C13119.98 (15)
O1—C1—C2110.16 (12)C11—C12—H12118.1 (9)
C3—C2—C1121.56 (14)C13—C12—H12122.0 (9)
C3—C2—H2120.4 (10)C14—C13—C12120.25 (17)
C1—C2—H2118.0 (10)C14—C13—H13120.5 (11)
C3—C2'—N1'119.17 (13)C12—C13—H13119.2 (11)
C3—C2'—C3'118.76 (13)C15—C14—C13119.91 (17)
N1'—C2'—C3'58.56 (9)C15—C14—H14120.1 (11)
C3—C2'—H2'117.0 (9)C13—C14—H14119.9 (11)
N1'—C2'—H2'112.9 (9)C14—C15—C16120.32 (17)
C3'—C2'—H2'117.4 (9)C14—C15—H15121.7 (12)
C2—C3—C2'122.97 (14)C16—C15—H15117.9 (12)
C2—C3—H3118.1 (10)C15—C16—C11120.09 (16)
C2'—C3—H3118.9 (10)C15—C16—H16121.3 (11)
N1'—C3'—C21117.27 (13)C11—C16—H16118.6 (11)
N1'—C3'—C2'59.36 (9)C26—C21—C22118.85 (15)
C21—C3'—C2'122.77 (13)C26—C21—C3'118.75 (14)
N1'—C3'—H3'114.5 (9)C22—C21—C3'122.34 (13)
C21—C3'—H3'116.9 (9)C23—C22—C21120.38 (15)
C2'—C3'—H3'113.4 (9)C23—C22—H22119.2 (10)
O1—C4—C5106.65 (14)C21—C22—H22120.3 (10)
O1—C4—H41107.5 (10)C22—C23—C24120.09 (17)
C5—C4—H41112.2 (10)C22—C23—H23119.7 (10)
O1—C4—H42108.5 (10)C24—C23—H23120.2 (10)
C5—C4—H42111.0 (10)C25—C24—C23119.73 (16)
H41—C4—H42110.9 (14)C25—C24—H24120.3 (12)
C4—C5—H51108.7 (12)C23—C24—H24120.0 (12)
C4—C5—H52108.8 (11)C24—C25—C26120.44 (16)
H51—C5—H52110.1 (17)C24—C25—H25120.5 (11)
C4—C5—H53109.3 (10)C26—C25—H25119.1 (11)
H51—C5—H53111.2 (16)C25—C26—C21120.47 (16)
H52—C5—H53108.8 (15)C25—C26—H26122.3 (10)
O3—C6—N1'121.39 (14)C21—C26—H26117.2 (10)
C5—C4—O1—C1178.44 (14)C12—C11—C6—N1'9.4 (2)
C4—O1—C1—C2179.57 (12)C11—C6—N1'—C3'149.00 (13)
O1—C1—C2—C3169.28 (14)C6—N1'—C3'—C21130.75 (14)
C1—C2—C3—C2'179.34 (14)N1'—C3'—C21—C2239.0 (2)
C2—C3—C2'—C3'159.78 (15)

Experimental details

Crystal data
Chemical formulaC20H19NO3
Mr321.36
Crystal system, space groupMonoclinic, P21/c
Temperature (K)150
a, b, c (Å)10.746 (1), 14.319 (1), 10.998 (1)
β (°) 93.52 (1)
V3)1689.1 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.4 × 0.3 × 0.2
Data collection
DiffractometerSMART 1K CCD area-detector
diffractometer
Absorption correctionMulti-scan
[SADABS (Sheldrick, 1998), before correction Rint = 0.054]
Tmin, Tmax0.757, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
17984, 3880, 2850
Rint0.046
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.097, 1.09
No. of reflections3880
No. of parameters294
H-atom treatmentAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.21, 0.23

Computer programs: SMART (Bruker, 1995), SMART, SAINT (Bruker, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998), SHELXTL.

Selected geometric parameters (Å, º) top
O1—C11.3432 (18)C1—C21.476 (2)
O1—C41.4577 (18)C2—C31.323 (2)
O2—C11.2087 (18)C2'—C31.468 (2)
O3—C61.2246 (17)C2'—C3'1.514 (2)
N1'—C61.3953 (19)C3'—C211.490 (2)
N1'—C3'1.4620 (19)C4—C51.501 (2)
N1'—C2'1.4745 (19)C6—C111.493 (2)
C1—O1—C4115.89 (12)N1'—C2'—C3'58.56 (9)
C6—N1'—C3'121.45 (12)C2—C3—C2'122.97 (14)
C6—N1'—C2'124.68 (12)N1'—C3'—C21117.27 (13)
C3'—N1'—C2'62.08 (9)N1'—C3'—C2'59.36 (9)
O2—C1—O1124.01 (14)C21—C3'—C2'122.77 (13)
O2—C1—C2125.83 (14)O1—C4—C5106.65 (14)
O1—C1—C2110.16 (12)O3—C6—N1'121.39 (14)
C3—C2—C1121.56 (14)O3—C6—C11122.10 (14)
C3—C2'—N1'119.17 (13)N1'—C6—C11116.25 (12)
C3—C2'—C3'118.76 (13)
 

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