tert-Butyl N-(thio­phen-2-yl)carbamate

Abstract

In the title compound, C₉H₁₃NO₂S, the dihedral angle between the thiophene ring and the carbamate group is 15.79 (14)°. In the crystal structure, 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  

• C₉H₁₃NO₂S

• M _r = 199.26

• Orthorhombic,

• a = 11.732 (2) Å

• b = 8.6513 (17) Å

• c = 9.879 (2) Å

• V = 1002.7 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.29 mm⁻¹

• T = 153 K

• 0.20 × 0.10 × 0.08 mm

Data collection  

• Nonius KappaCCD diffractometer

• Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997 ▶) T _min = 0.944, T _max = 0.977

• 2112 measured reflections

• 2112 independent reflections

• 1816 reflections with I > 2σ(I)

Refinement  

• R[F ² > 2σ(F ²)] = 0.034

• wR(F ²) = 0.078

• S = 1.04

• 2112 reflections

• 125 parameters

• 2 restraints

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.25 e Å⁻³

• Δρ_min = −0.19 e Å⁻³

• Absolute structure: Flack x determined using 703 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons & Flack, 2004 ▶)

• Absolute structure parameter: 0.53 (4)

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: 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 ▶).

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

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

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) .

supplementary crystallographic information

1. Comment

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).

2. Experimental

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 structure determination were obtained by cooling a toluene solution to -30 °C. ¹H NMR (400 MHz, chloroform-d): δ=6.9(br, 1H, –NH), 6.79(m, 2H, –CH), 6.5(dd, 1H, –CH), 1.5(s, 9H, tBu).

3. Refinement

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 U_iso(H) = 1.2 U_eq(thiophene H atom) or U_iso(H) = 1.5 U_eq(methyl H atom).

Figures

Fig. 1.

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

Crystal data

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

Data collection

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

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)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	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*

Atomic displacement parameters (Ų)

	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)

Geometric parameters (Å, º)

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)

Hydrogen-bond geometry (Å, º)

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.