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organic compounds
tert-Butyl N-(thiophen-2-yl)carbamate
aDepartment of Chemistry & Biochemistry, Texas Tech University, Memorial Circle & Boston, Lubbock, TX 79409, USA
*Correspondence e-mail: michael.findlater@ttu.edu
In the title compound, C9H13NO2S, the dihedral angle between the thiophene ring and the carbamate group is 15.79 (14)°. In the intramolecular C—H⋯O interactions in tandem with the tert-butyl groups render the packing of adjacent molecules in the [001] direction nearly perpendicular [the angle between adjacent thiophene rings is 74.83 (7)°]. An intermolecular N—H⋯O hydrogen bond gives rise to a chain extending along [001]. The crystal studied was found to be a racemic twin.
Related literature
For the synthesis of the title compound, see: Binder et al. (1977); Kruse et al. (1989
). For related structures, see: Arsenyan et al. (2008
); Elshaarawy & Janiak (2011
); Low et al. (2009
); Hsu et al. (2013
).
Experimental
Crystal data
|
Refinement
|
Data collection: COLLECT (Nonius, 1998); cell COLLECT; data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997
); program(s) used to solve structure: SIR97 (Altomare et al., 1999
); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008
); molecular graphics: SHELXTL (Sheldrick, 2008
); software used to prepare material for publication: SHELXTL, enCIFer (Allen et al., 2004
) and publCIF (Westrip, 2010
).
Supporting information
10.1107/S160053681302196X/zs2273sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681302196X/zs2273Isup2.hkl
Supporting information file. DOI: 10.1107/S160053681302196X/zs2273Isup3.cml
The title compound was prepared by a typical Curtius Rearrangement. Thiophene-2-carbonyl azide (270 mg; 1.77 mmol) was reacted with 1.0 equivalent of tert-butyl alcohol (131 mg; 1.77 mmol) and dissolved in 15 ml of toluene. The solution was heated at 100 °C overnight. Excess solvent and tert-butyl alcohol was removed in vacuo. Crystals suitable for X-ray δ=6.9(br, 1H, –NH), 6.79(m, 2H, –CH), 6.5(dd, 1H, –CH), 1.5(s, 9H, tBu).
were obtained by cooling a toluene solution to -30 °C. 1H NMR (400 MHz, chloroform-d):The NH hydrogen atom was located from the difference-Fourier map and refined isotropically subject to a distance restraint (N—H = 0.98 Å). Carbon-bound H atoms were included in calculated positions (C—H distances are 0.98 Å for methyl H atoms and 0.95 Å for thiophene H atoms) and refined as riding atoms with Uiso(H) = 1.2 Ueq(thiophene H atom) or Uiso(H) = 1.5 Ueq(methyl H atom).
Data collection: COLLECT (Nonius, 1998); cell
COLLECT (Nonius, 1998); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010). ![]() | Fig. 1. The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. |
C9H13NO2S | Dx = 1.320 Mg m−3 |
Mr = 199.26 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pca21 | Cell parameters from 1327 reflections |
a = 11.732 (2) Å | θ = 1.0–27.5° |
b = 8.6513 (17) Å | µ = 0.29 mm−1 |
c = 9.879 (2) Å | T = 153 K |
V = 1002.7 (3) Å3 | Rod, colorless |
Z = 4 | 0.20 × 0.10 × 0.08 mm |
F(000) = 424 |
Nonius KappaCCD diffractometer | 2112 independent reflections |
Radiation source: fine-focus sealed tube | 1816 reflections with I > 2σ(I) |
ϕ and ω scans | θmax = 27.5°, θmin = 2.4° |
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997) | h = −15→15 |
Tmin = 0.944, Tmax = 0.977 | k = −11→11 |
2112 measured reflections | l = −12→12 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.034 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.078 | w = 1/[σ2(Fo2) + (0.0301P)2 + 0.2397P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max < 0.001 |
2112 reflections | Δρmax = 0.25 e Å−3 |
125 parameters | Δρmin = −0.19 e Å−3 |
2 restraints | Absolute structure: Flack x determined using 703 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons & Flack, 2004). |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.53 (4) |
C9H13NO2S | V = 1002.7 (3) Å3 |
Mr = 199.26 | Z = 4 |
Orthorhombic, Pca21 | Mo Kα radiation |
a = 11.732 (2) Å | µ = 0.29 mm−1 |
b = 8.6513 (17) Å | T = 153 K |
c = 9.879 (2) Å | 0.20 × 0.10 × 0.08 mm |
Nonius KappaCCD diffractometer | 2112 measured reflections |
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997) | 2112 independent reflections |
Tmin = 0.944, Tmax = 0.977 | 1816 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.034 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.078 | Δρmax = 0.25 e Å−3 |
S = 1.04 | Δρmin = −0.19 e Å−3 |
2112 reflections | Absolute structure: Flack x determined using 703 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons & Flack, 2004). |
125 parameters | Absolute structure parameter: 0.53 (4) |
2 restraints |
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. |
x | y | z | Uiso*/Ueq | ||
S1 | 0.13622 (6) | 0.05380 (7) | 0.63359 (7) | 0.02745 (19) | |
O1 | 0.29399 (16) | 0.2992 (2) | 0.61913 (19) | 0.0273 (4) | |
O2 | 0.32467 (18) | 0.4564 (2) | 0.80079 (18) | 0.0289 (5) | |
N1 | 0.23352 (19) | 0.2367 (2) | 0.8305 (2) | 0.0224 (5) | |
H1N | 0.238 (3) | 0.264 (4) | 0.919 (2) | 0.036 (9)* | |
C1 | 0.1713 (2) | 0.1041 (3) | 0.7987 (3) | 0.0209 (5) | |
C2 | 0.1219 (3) | 0.0067 (3) | 0.8902 (3) | 0.0241 (6) | |
H2 | 0.1317 | 0.0150 | 0.9854 | 0.029* | |
C3 | 0.0542 (2) | −0.1082 (3) | 0.8269 (3) | 0.0289 (6) | |
H3 | 0.0137 | −0.1855 | 0.8754 | 0.035* | |
C4 | 0.0533 (3) | −0.0964 (3) | 0.6907 (3) | 0.0306 (7) | |
H4 | 0.0115 | −0.1635 | 0.6329 | 0.037* | |
C5 | 0.2857 (2) | 0.3295 (3) | 0.7389 (3) | 0.0220 (6) | |
C6 | 0.3798 (2) | 0.5829 (3) | 0.7233 (3) | 0.0250 (6) | |
C7 | 0.3034 (3) | 0.6385 (4) | 0.6108 (4) | 0.0438 (9) | |
H7A | 0.2928 | 0.5554 | 0.5446 | 0.066* | |
H7B | 0.3384 | 0.7280 | 0.5663 | 0.066* | |
H7C | 0.2292 | 0.6684 | 0.6483 | 0.066* | |
C8 | 0.4940 (3) | 0.5271 (4) | 0.6722 (4) | 0.0445 (9) | |
H8A | 0.5384 | 0.4856 | 0.7480 | 0.067* | |
H8B | 0.5354 | 0.6135 | 0.6310 | 0.067* | |
H8C | 0.4823 | 0.4458 | 0.6045 | 0.067* | |
C9 | 0.3945 (3) | 0.7083 (3) | 0.8284 (4) | 0.0459 (9) | |
H9A | 0.3196 | 0.7408 | 0.8617 | 0.069* | |
H9B | 0.4337 | 0.7970 | 0.7878 | 0.069* | |
H9C | 0.4399 | 0.6685 | 0.9040 | 0.069* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0369 (4) | 0.0261 (3) | 0.0194 (3) | −0.0050 (3) | 0.0003 (3) | −0.0034 (3) |
O1 | 0.0377 (11) | 0.0268 (9) | 0.0173 (10) | −0.0043 (8) | 0.0014 (9) | −0.0012 (8) |
O2 | 0.0425 (12) | 0.0258 (10) | 0.0182 (9) | −0.0120 (8) | 0.0029 (9) | 0.0003 (8) |
N1 | 0.0293 (13) | 0.0232 (11) | 0.0147 (9) | −0.0051 (9) | 0.0006 (10) | −0.0009 (10) |
C1 | 0.0234 (13) | 0.0211 (12) | 0.0183 (12) | 0.0033 (11) | 0.0000 (11) | −0.0012 (11) |
C2 | 0.0277 (16) | 0.0226 (13) | 0.0221 (13) | 0.0002 (11) | −0.0017 (11) | 0.0006 (11) |
C3 | 0.0300 (16) | 0.0227 (14) | 0.0340 (15) | −0.0037 (12) | −0.0002 (13) | 0.0029 (13) |
C4 | 0.0329 (18) | 0.0259 (15) | 0.0330 (15) | −0.0030 (12) | −0.0029 (14) | −0.0039 (13) |
C5 | 0.0238 (15) | 0.0227 (14) | 0.0195 (15) | 0.0016 (11) | −0.0023 (11) | −0.0005 (11) |
C6 | 0.0288 (17) | 0.0228 (14) | 0.0234 (13) | −0.0047 (12) | 0.0053 (11) | 0.0019 (11) |
C7 | 0.0453 (19) | 0.0306 (15) | 0.056 (2) | −0.0046 (14) | −0.0128 (18) | 0.0135 (16) |
C8 | 0.0299 (17) | 0.0339 (16) | 0.070 (2) | −0.0022 (13) | 0.0128 (18) | 0.0021 (16) |
C9 | 0.070 (2) | 0.0327 (17) | 0.0347 (17) | −0.0212 (17) | 0.0122 (17) | −0.0068 (15) |
S1—C4 | 1.718 (3) | C4—H4 | 0.9500 |
S1—C1 | 1.737 (3) | C6—C7 | 1.507 (4) |
O1—C5 | 1.216 (3) | C6—C8 | 1.511 (4) |
O2—C5 | 1.337 (3) | C6—C9 | 1.512 (4) |
O2—C6 | 1.484 (3) | C7—H7A | 0.9800 |
N1—C5 | 1.356 (3) | C7—H7B | 0.9800 |
N1—C1 | 1.396 (3) | C7—H7C | 0.9800 |
N1—H1N | 0.90 (2) | C8—H8A | 0.9800 |
C1—C2 | 1.365 (4) | C8—H8B | 0.9800 |
C2—C3 | 1.418 (4) | C8—H8C | 0.9800 |
C2—H2 | 0.9500 | C9—H9A | 0.9800 |
C3—C4 | 1.350 (4) | C9—H9B | 0.9800 |
C3—H3 | 0.9500 | C9—H9C | 0.9800 |
C4—S1—C1 | 90.88 (14) | C7—C6—C8 | 112.6 (3) |
C5—O2—C6 | 121.3 (2) | O2—C6—C9 | 103.0 (2) |
C5—N1—C1 | 124.9 (2) | C7—C6—C9 | 110.2 (3) |
C5—N1—H1N | 117 (2) | C8—C6—C9 | 111.0 (3) |
C1—N1—H1N | 118 (2) | C6—C7—H7A | 109.5 |
C2—C1—N1 | 125.4 (2) | C6—C7—H7B | 109.5 |
C2—C1—S1 | 111.5 (2) | H7A—C7—H7B | 109.5 |
N1—C1—S1 | 122.77 (19) | C6—C7—H7C | 109.5 |
C1—C2—C3 | 112.2 (3) | H7A—C7—H7C | 109.5 |
C1—C2—H2 | 123.9 | H7B—C7—H7C | 109.5 |
C3—C2—H2 | 123.9 | C6—C8—H8A | 109.5 |
C4—C3—C2 | 113.0 (3) | C6—C8—H8B | 109.5 |
C4—C3—H3 | 123.5 | H8A—C8—H8B | 109.5 |
C2—C3—H3 | 123.5 | C6—C8—H8C | 109.5 |
C3—C4—S1 | 112.3 (2) | H8A—C8—H8C | 109.5 |
C3—C4—H4 | 123.8 | H8B—C8—H8C | 109.5 |
S1—C4—H4 | 123.8 | C6—C9—H9A | 109.5 |
O1—C5—O2 | 126.4 (2) | C6—C9—H9B | 109.5 |
O1—C5—N1 | 123.9 (2) | H9A—C9—H9B | 109.5 |
O2—C5—N1 | 109.6 (2) | C6—C9—H9C | 109.5 |
O2—C6—C7 | 110.9 (2) | H9A—C9—H9C | 109.5 |
O2—C6—C8 | 108.8 (2) | H9B—C9—H9C | 109.5 |
C5—N1—C1—C2 | 177.5 (3) | C1—S1—C4—C3 | −0.9 (3) |
C5—N1—C1—S1 | −8.9 (4) | C6—O2—C5—O1 | 3.3 (4) |
C4—S1—C1—C2 | 0.9 (2) | C6—O2—C5—N1 | −176.4 (2) |
C4—S1—C1—N1 | −173.5 (2) | C1—N1—C5—O1 | −7.8 (4) |
N1—C1—C2—C3 | 173.6 (2) | C1—N1—C5—O2 | 171.9 (2) |
S1—C1—C2—C3 | −0.7 (3) | C5—O2—C6—C7 | 54.5 (3) |
C1—C2—C3—C4 | 0.0 (4) | C5—O2—C6—C8 | −69.8 (3) |
C2—C3—C4—S1 | 0.7 (4) | C5—O2—C6—C9 | 172.4 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O1i | 0.90 (2) | 2.04 (2) | 2.920 (3) | 165 (3) |
C7—H7A···O1 | 0.98 | 2.33 | 2.938 (4) | 119 |
C8—H8C···O1 | 0.98 | 2.55 | 3.109 (4) | 116 |
Symmetry code: (i) −x+1/2, y, z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O1i | 0.90 (2) | 2.04 (2) | 2.920 (3) | 165 (3) |
C7—H7A···O1 | 0.98 | 2.33 | 2.938 (4) | 119.0 |
C8—H8C···O1 | 0.98 | 2.55 | 3.109 (4) | 116.0 |
Symmetry code: (i) −x+1/2, y, z+1/2. |
Acknowledgements
The authors gratefully acknowledge the Robert A. Welch Foundation for their support of GCH via the Welch Summer Scholars Program, and Texas Tech University for start-up funds.
References
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The title compound tert-butyl N-(thiophene-2-yl)carbamate, C9H13NO2S, (Fig. 1) is a precursor in the synthesis of diimine ligands suitable for metal complex formation. This compound exhibits intramolecular methyl C7—H···O1 and C8—H···O1 interactions [2.938 (4) and 3.109 (4), respectively] in addition to bulky tert -butyl groups. These two features in tandem allow the packing in the crystal to be nearly perpendicular [the angle between adjacent thiophene rings = 74.83 (7)°]. An intermolecular N1—H···O1i hydrogen bond (Table 1) gives a one-dimensional chain which extends along [0 0 1]. The compound was synthesized via a typical Curtius Rearrangement from thiophene-2-carbonyl azide (Binder et al., 1977; Kruse et al., 1989).