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Acta Crystallographica Section E: Crystallographic Communications logoLink to Acta Crystallographica Section E: Crystallographic Communications
. 2021 Jul 13;77(Pt 8):785–787. doi: 10.1107/S2056989021006927

Crystal structure of 2-oxo-2-phenyl­ethyl diiso­propyl­carbamate

Viktor Martens a, Helmar Görls b, Wolfgang Imhof a,*
PMCID: PMC8340964  PMID: 34422301

In the mol­ecular structure of the title compound, the urethane function and the benzoyl group are almost perpendicular to each other [dihedral angle 88.97 (5)°]. In the crystal structure, infinite supra­molecular layers in the bc plane are formed by weak C—H⋯O hydrogen bonds.

Keywords: crystal structure, urethanes, carbamates, C—H⋯O hydrogen bonds

Abstract

In the mol­ecular structure of the title compound, C15H21NO3, the urethane function and the benzoyl group are almost perpendicular to each other [dihedral angle 88.97 (5)°]. In the crystal structure, infinite supra­molecular layers in the bc plane are formed by weak C—H⋯O hydrogen bonds.

Chemical context  

Phenacyl and desyl compounds have been a subject of inter­est for many years due to their use as photoremovable protecting groups (PPGs) (Givens et al., 2012 ▸; Kammari et al., 2007 ▸; Klán et al., 2013 ▸; Sheehan & Umezawa, 1973 ▸). Carbamates are used for the protection of carb­oxy­lic acids and may also act as suitable protecting groups for amines (Speckmeier et al., 2018 ▸). Speckmeier and co-workers synthesized several phenacyl urethanes, but the protection of diiso­propyl­amine by a phenacyl group has not been reported so far. The title compound was synthesized according to reported routes (Speckmeier et al., 2018 ▸). graphic file with name e-77-00785-scheme1.jpg

Structural commentary  

As expected, the carbamate functional moiety (N1/C3/O3/O2) is essentially planar (maximum deviation of 0.01 Å for C3). The same is true for the benzoyl group (C1/O1/C10–C15, maximum deviation of 0.05 Å for O1). These two planes subtend a dihedral angle of 88.97 (5)° and therefore an almost perpendicular arrangement (Fig. 1 ▸). Otherwise, the bond lengths and angles are of expected values with C3—N1 [1.348 (2) Å] and C3—O2 [1.368 (2) Å] being slightly shorter than a typical C—O or C—N single bond due to the partial double-bond character of the respective bonds in a carbamate.

Figure 1.

Figure 1

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Mol­ecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.

Supra­molecular features  

The crystal structure of the title compound features weak hydrogen bonds (Desiraju & Steiner, 2001 ▸) of the C—H⋯O type, as shown in Table 1 ▸. The inter­action C5—H5B⋯O3 links mol­ecules of the title compound into infinite chains parallel to the c-axis direction. Additional C2—H2B⋯O1 and C9—H9B⋯O2 inter­actions link these infinite chains to a supra­molecular sheet parallel to the bc plane (Fig. 2 ▸). The latter inter­action is accompanied by a short C9—H9B⋯C3 contact, which makes the contact look like a non-classical hydrogen bond towards the π-system of a C=O double bond, again showing the partial double-bond character of the respective bond.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C2—H2B⋯O1i 0.99 2.70 3.605 (2) 152
C5—H5B⋯O3ii 0.98 2.62 3.578 (2) 167
C9—H9B⋯O2iii 0.98 2.68 3.599 (2) 157
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Symmetry codes: (i) x, y-1, z; (ii) x, -y+{\script{3\over 2}}, z+{\script{1\over 2}}; (iii) x, y+1, z.

Figure 2.

Figure 2

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Crystal structure of the title compound showing layers of mol­ecules along the bc plane that are built up by C—H⋯O hydrogen bonds.

Database survey  

In the CSD (ConQuest Version 2020.3.0; Groom et al., 2016 ▸), only one other carbamate with a CH2–C(O)-Ph group attached to the carbamate oxygen atom is reported (NIWQUI; Jiang et al., 2019 ▸). The respective compound shows a di­ethyl­amino group and a p-chloro­phenyl substituent instead of the diiso­propyl­amino group and the non-substituted phenyl group in the title compound. In contrast to the title compound, the carbamate plane and the benzoyl plane are almost coplanar. The carbonyl oxygen atoms show numerous short contacts towards different C—H groups of neighboring mol­ecules, leading to a dense three-dimensional network.

Synthesis and crystallization  

Diiso­propyl­amine (0.05 mol, 5.05 g) and 1 equiv. of cesium carbonate (0.05 mol, 16.55 g) were placed in a Schlenk tube and dissolved in anhydrous DMSO (150 mL). The tube was sealed with a septum and two balloons filled with CO2 were bubbled through the reaction mixture within one h while stirring. After the addition of CO2, 1.1 equiv. of 2-bromo-1-phenyl­ethan-1-one (0.055 mol, 10.95 g) dissolved in a small amount of DMSO was added in one portion. The consumption of 2-bromo-1-phenyl­ethan-1-one was monitored by TLC and after 30 min the reaction mixture was poured on ice to quench the reaction. After extraction with di­chloro­methane (3×), the combined organic phases were washed with brine, separated and dried over Na2SO4. The solvent was removed in vacuo and the crude product was recrystallized from n-hexa­ne/ethanol (4:1) to afford the title compound (12.90 g; 98%) as a colorless solid, m.p. 347.5°C. 1H NMR (500 MHz, CDCl3) [ppm]: δ = 7.90 (dd, 2H), 7.55 (ddt, 1H), 7.45 (dd, J = 8.4, 7.1 Hz, 2H), 5.33 (s, 2H), 3.97 (hept, 2H), 1.25 (d, 12H); 13C NMR (126 MHz, CDCl3) [ppm]: δ = 193.91 (C=O), 154.80 (NC=O), 134.69, 133.65, 128.84, 127.83 (C ar), 66.36 (O=C—O), 46.32 [(H3C)2 CH–], 20.99 [(H3 C)2CH–].

Refinement  

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. All hydrogen atoms were placed in idealized positions (C—H = 0.95–0.99Å) and refined using a riding model with isotropic displacement parameters calculated as U iso(H) = 1.2×U eq(C) for methyl­ene and hydrogen atoms of the phenyl group or 1.5×U eq(C) for methyl groups.

Table 2. Experimental details.

Crystal data
Chemical formula C15H21NO3
M r 263.33
Crystal system, space group Monoclinic, P21/c
Temperature (K) 133
a, b, c (Å) 18.4574 (8), 5.7020 (2), 14.8058 (6)
β (°) 113.468 (1)
V (Å3) 1429.33 (10)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.09
Crystal size (mm) 0.10 × 0.10 × 0.08
 
Data collection
Diffractometer Nonius KappaCCD
Absorption correction Multi-scan (SADABS; Krause et al., 2015 ▸)
T min, T max 0.674, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 13968, 3280, 2464
R int 0.040
(sin θ/λ)max (Å−1) 0.649
 
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S 0.049, 0.113, 1.04
No. of reflections 3280
No. of parameters 177
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.27, −0.21
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Computer programs: COLLECT (Nonius 1998 ▸), DENZO (Otwinowski & Minor, 1997 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2018/3 (Sheldrick, 2015 ▸), ORTEP-3 (Farrugia, 2012 ▸) and Mercury (Macrae et al., 2020 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021006927/zl5014sup1.cif

e-77-00785-sup1.cif (517.2KB, cif)

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989021006927/zl5014Isup2.hkl

e-77-00785-Isup2.hkl (262KB, hkl)
Click here for additional data file. (5.1KB, cml)

Supporting information file. DOI: 10.1107/S2056989021006927/zl5014Isup3.cml

CCDC reference: 2094771

Additional supporting information: crystallographic information; 3D view; checkCIF report

Acknowledgments

Financial support of the PhD project of VM by Lohmann GmbH & Co. KG, Neuwied, Germany, is gratefully acknowledged.

supplementary crystallographic information

Crystal data

C15H21NO3 F(000) = 568
Mr = 263.33 Dx = 1.224 Mg m−3
Monoclinic, P21/c Mo Kα radiation, λ = 0.71073 Å
a = 18.4574 (8) Å Cell parameters from 13968 reflections
b = 5.7020 (2) Å θ = 2.8–27.5°
c = 14.8058 (6) Å µ = 0.09 mm−1
β = 113.468 (1)° T = 133 K
V = 1429.33 (10) Å3 Prism, colourless
Z = 4 0.10 × 0.10 × 0.08 mm
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Data collection

Nonius KappaCCD diffractometer 2464 reflections with I > 2σ(I)
phi + ω – scans Rint = 0.040
Absorption correction: multi-scan (SADABS; Krause et al., 2015) θmax = 27.5°, θmin = 2.8°
Tmin = 0.674, Tmax = 0.746 h = −23→23
13968 measured reflections k = −5→7
3280 independent reflections l = −19→18
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Refinement

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)] = 0.049 H-atom parameters constrained
wR(F2) = 0.113 w = 1/[σ2(Fo2) + (0.0368P)2 + 0.6743P] where P = (Fo2 + 2Fc2)/3
S = 1.04 (Δ/σ)max < 0.001
3280 reflections Δρmax = 0.27 e Å−3
177 parameters Δρmin = −0.21 e Å−3
0 restraints Extinction correction: SHELXL2018/3 (Sheldrick 2015)
Primary atom site location: structure-invariant direct methods Extinction coefficient: 0.0093 (16)
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Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

x y z Uiso*/Ueq
O1 0.38605 (6) 0.7949 (2) 0.38826 (9) 0.0338 (3)
O2 0.27936 (6) 0.4581 (2) 0.32610 (8) 0.0280 (3)
O3 0.24228 (6) 0.6202 (2) 0.17458 (8) 0.0285 (3)
N1 0.17054 (7) 0.6836 (3) 0.26709 (9) 0.0285 (3)
C1 0.41005 (8) 0.6137 (3) 0.36687 (11) 0.0234 (3)
C2 0.35448 (8) 0.4079 (3) 0.32488 (12) 0.0257 (3)
H2A 0.348514 0.377390 0.256450 0.031*
H2B 0.376866 0.265560 0.364461 0.031*
C3 0.23136 (8) 0.5945 (3) 0.24965 (11) 0.0249 (3)
C4 0.16762 (9) 0.6747 (4) 0.36534 (12) 0.0371 (4)
H4 0.211633 0.570586 0.407718 0.044*
C5 0.18152 (13) 0.9155 (5) 0.41331 (15) 0.0605 (7)
H5A 0.228794 0.985787 0.409862 0.091*
H5B 0.188987 0.899895 0.482386 0.091*
H5C 0.135734 1.015930 0.378631 0.091*
C6 0.09072 (11) 0.5665 (4) 0.36026 (15) 0.0452 (5)
H6A 0.046572 0.670305 0.322993 0.068*
H6B 0.093071 0.545940 0.427083 0.068*
H6C 0.083000 0.413759 0.327431 0.068*
C7 0.11069 (9) 0.8271 (3) 0.19039 (11) 0.0278 (4)
H7 0.074178 0.887235 0.220031 0.033*
C8 0.06055 (9) 0.6780 (3) 0.10240 (12) 0.0319 (4)
H8A 0.019602 0.775918 0.054376 0.048*
H8B 0.035643 0.551161 0.124422 0.048*
H8C 0.094128 0.610990 0.071729 0.048*
C9 0.14496 (11) 1.0413 (3) 0.16096 (14) 0.0405 (5)
H9A 0.176297 0.991762 0.124230 0.061*
H9B 0.178789 1.126741 0.220191 0.061*
H9C 0.101940 1.143637 0.119443 0.061*
C10 0.49370 (8) 0.5861 (3) 0.37810 (11) 0.0248 (3)
C11 0.51983 (9) 0.3863 (3) 0.34607 (12) 0.0315 (4)
H11 0.484354 0.260546 0.317232 0.038*
C12 0.59781 (10) 0.3710 (4) 0.35634 (13) 0.0420 (5)
H12 0.615586 0.234665 0.334388 0.050*
C13 0.64925 (10) 0.5519 (4) 0.39804 (13) 0.0478 (6)
H13 0.702529 0.540331 0.404875 0.057*
C14 0.62389 (10) 0.7512 (4) 0.43024 (13) 0.0437 (5)
H14 0.659736 0.876252 0.458872 0.052*
C15 0.54637 (9) 0.7686 (3) 0.42078 (12) 0.0327 (4)
H15 0.529143 0.904967 0.443406 0.039*
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Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23
O1 0.0316 (6) 0.0311 (6) 0.0386 (7) 0.0050 (5) 0.0140 (5) −0.0076 (5)
O2 0.0204 (5) 0.0369 (6) 0.0260 (6) 0.0011 (5) 0.0087 (4) 0.0069 (5)
O3 0.0261 (5) 0.0375 (7) 0.0229 (6) 0.0009 (5) 0.0108 (4) 0.0031 (5)
N1 0.0201 (6) 0.0433 (8) 0.0219 (7) 0.0018 (6) 0.0081 (5) 0.0037 (6)
C1 0.0248 (7) 0.0269 (8) 0.0182 (7) 0.0041 (6) 0.0080 (6) 0.0014 (6)
C2 0.0227 (7) 0.0278 (8) 0.0264 (8) 0.0023 (6) 0.0095 (6) 0.0021 (6)
C3 0.0199 (7) 0.0310 (8) 0.0211 (7) −0.0038 (6) 0.0055 (6) 0.0007 (6)
C4 0.0257 (8) 0.0627 (13) 0.0251 (8) 0.0034 (8) 0.0125 (7) 0.0044 (8)
C5 0.0611 (13) 0.0909 (18) 0.0325 (10) −0.0377 (13) 0.0217 (10) −0.0224 (11)
C6 0.0487 (11) 0.0512 (12) 0.0475 (11) −0.0061 (9) 0.0314 (9) 0.0003 (9)
C7 0.0218 (7) 0.0317 (9) 0.0269 (8) 0.0026 (6) 0.0065 (6) −0.0008 (7)
C8 0.0251 (7) 0.0352 (9) 0.0289 (8) −0.0006 (7) 0.0041 (7) −0.0019 (7)
C9 0.0418 (10) 0.0327 (10) 0.0417 (10) −0.0035 (8) 0.0108 (8) 0.0002 (8)
C10 0.0227 (7) 0.0335 (9) 0.0174 (7) 0.0036 (6) 0.0069 (6) 0.0035 (6)
C11 0.0278 (8) 0.0404 (10) 0.0257 (8) 0.0066 (7) 0.0101 (7) 0.0001 (7)
C12 0.0323 (9) 0.0672 (13) 0.0276 (9) 0.0201 (9) 0.0133 (7) 0.0047 (9)
C13 0.0209 (8) 0.0923 (17) 0.0311 (10) 0.0091 (10) 0.0111 (7) 0.0159 (10)
C14 0.0265 (8) 0.0666 (14) 0.0318 (10) −0.0123 (9) 0.0051 (7) 0.0068 (9)
C15 0.0288 (8) 0.0404 (10) 0.0252 (8) −0.0038 (7) 0.0068 (7) 0.0003 (7)
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Geometric parameters (Å, º)

O1—C1 1.2149 (19) C7—C9 1.517 (2)
O2—C3 1.3684 (18) C7—C8 1.522 (2)
O2—C2 1.4230 (17) C7—H7 1.0000
O3—C3 1.2148 (18) C8—H8A 0.9800
N1—C3 1.348 (2) C8—H8B 0.9800
N1—C7 1.4764 (19) C8—H8C 0.9800
N1—C4 1.478 (2) C9—H9A 0.9800
C1—C10 1.494 (2) C9—H9B 0.9800
C1—C2 1.519 (2) C9—H9C 0.9800
C2—H2A 0.9900 C10—C15 1.392 (2)
C2—H2B 0.9900 C10—C11 1.392 (2)
C4—C5 1.520 (3) C11—C12 1.389 (2)
C4—C6 1.522 (2) C11—H11 0.9500
C4—H4 1.0000 C12—C13 1.371 (3)
C5—H5A 0.9800 C12—H12 0.9500
C5—H5B 0.9800 C13—C14 1.384 (3)
C5—H5C 0.9800 C13—H13 0.9500
C6—H6A 0.9800 C14—C15 1.385 (2)
C6—H6B 0.9800 C14—H14 0.9500
C6—H6C 0.9800 C15—H15 0.9500
C3—O2—C2 114.64 (12) N1—C7—C8 111.27 (13)
C3—N1—C7 119.12 (13) C9—C7—C8 112.63 (14)
C3—N1—C4 122.37 (13) N1—C7—H7 106.3
C7—N1—C4 117.83 (13) C9—C7—H7 106.3
O1—C1—C10 121.89 (14) C8—C7—H7 106.3
O1—C1—C2 120.45 (14) C7—C8—H8A 109.5
C10—C1—C2 117.64 (13) C7—C8—H8B 109.5
O2—C2—C1 110.00 (13) H8A—C8—H8B 109.5
O2—C2—H2A 109.7 C7—C8—H8C 109.5
C1—C2—H2A 109.7 H8A—C8—H8C 109.5
O2—C2—H2B 109.7 H8B—C8—H8C 109.5
C1—C2—H2B 109.7 C7—C9—H9A 109.5
H2A—C2—H2B 108.2 C7—C9—H9B 109.5
O3—C3—N1 125.75 (14) H9A—C9—H9B 109.5
O3—C3—O2 122.46 (14) C7—C9—H9C 109.5
N1—C3—O2 111.72 (13) H9A—C9—H9C 109.5
N1—C4—C5 111.30 (16) H9B—C9—H9C 109.5
N1—C4—C6 111.37 (14) C15—C10—C11 119.50 (15)
C5—C4—C6 111.69 (16) C15—C10—C1 118.42 (15)
N1—C4—H4 107.4 C11—C10—C1 122.07 (14)
C5—C4—H4 107.4 C12—C11—C10 119.92 (17)
C6—C4—H4 107.4 C12—C11—H11 120.0
C4—C5—H5A 109.5 C10—C11—H11 120.0
C4—C5—H5B 109.5 C13—C12—C11 120.25 (18)
H5A—C5—H5B 109.5 C13—C12—H12 119.9
C4—C5—H5C 109.5 C11—C12—H12 119.9
H5A—C5—H5C 109.5 C12—C13—C14 120.29 (16)
H5B—C5—H5C 109.5 C12—C13—H13 119.9
C4—C6—H6A 109.5 C14—C13—H13 119.9
C4—C6—H6B 109.5 C13—C14—C15 120.11 (18)
H6A—C6—H6B 109.5 C13—C14—H14 119.9
C4—C6—H6C 109.5 C15—C14—H14 119.9
H6A—C6—H6C 109.5 C14—C15—C10 119.93 (18)
H6B—C6—H6C 109.5 C14—C15—H15 120.0
N1—C7—C9 113.40 (13) C10—C15—H15 120.0
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Hydrogen-bond geometry (Å, º)

D—H···A D—H H···A D···A D—H···A
C2—H2B···O1i 0.99 2.70 3.605 (2) 152
C5—H5B···O3ii 0.98 2.62 3.578 (2) 167
C9—H9B···O2iii 0.98 2.68 3.599 (2) 157
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Symmetry codes: (i) x, y−1, z; (ii) x, −y+3/2, z+1/2; (iii) x, y+1, z.

References

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  4. Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. [DOI] [PMC free article] [PubMed]
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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989021006927/zl5014sup1.cif

e-77-00785-sup1.cif (517.2KB, cif)

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989021006927/zl5014Isup2.hkl

e-77-00785-Isup2.hkl (262KB, hkl)
Click here for additional data file. (5.1KB, cml)

Supporting information file. DOI: 10.1107/S2056989021006927/zl5014Isup3.cml

CCDC reference: 2094771

Additional supporting information: crystallographic information; 3D view; checkCIF report

Articles from Acta Crystallographica Section E: Crystallographic Communications are provided here courtesy of International Union of Crystallography

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