Ethyl 2-(tert-butoxy­carbonyl­amino)-1,3-benzothia­zole-6-carboxyl­ate

Lei, C.; Fang, X.; Yu, H.-Y.; Huang, M.-D.; Wang, J.-D.

doi:10.1107/S160053681001024X

organic compounds

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ISSN: 2056-9890

Volume 66| Part 4| April 2010| Page o914

doi:10.1107/S160053681001024X

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Ethyl 2-(tert-butoxycarbonylamino)-1,3-benzothiazole-6-carboxylate

Can Lei,^a Xin Fang,^a Hai-Yang Yu,^a Ming-Dong Huang ^b and Jun-Dong Wang ^a ^*

^aCollege of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108, People's Republic of China, and ^bFujian Institute of Research on the Structure of Matter, State Key Laboratory of Structural Chemistry, Chinese Academy of Sciences, Fuzhou 350108, People's Republic of China
^*Correspondence e-mail: wangjd@fzu.edu.cn

(Received 22 February 2010; accepted 18 March 2010; online 24 March 2010)

In the crystal of the title compound, C₁₅H₁₈N₂O₄S, inversion dimers are formed by intermolecular N—H⋯N hydrogen bonds and weak C—H⋯O contacts. These dimers stack up along [100] through inversion-related π–π interactions between thiazole rings [centroid–centroid distance = 3.790 (2) Å] and the thiazole and benzene rings [centroid–centroid distance = 3.845 (2) Å] and C—H⋯π contacts.

Related literature

For benzothiazole derivatives with anti-tumor activity, see: Brantley et al. (2004 ); Ćaleta et al. (2009 ); Mortimer et al. (2006 ) and for anti-tuberculous benzothiazolines, see: Palmer et al. (1971 ). For related benzothiazole structures, see: Lynch et al. (2002 ); Matković-Čalogović et al. (2003 ).

Experimental

Crystal data

C₁₅H₁₈N₂O₄S
M_r = 322.37
Triclinic, $[P \overline 1]$
a = 6.3026 (13) Å
b = 10.791 (2) Å
c = 11.909 (2) Å
α = 80.58 (3)°
β = 86.61 (3)°
γ = 81.57 (3)°
V = 789.9 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 293 K
0.70 × 0.05 × 0.02 mm

Data collection

Rigaku Saturn 724 CCD area-detector diffractometer
Absorption correction: numerical (NUMABS; Higashi, 2000 ) T_min = 0.987, T_max = 0.995
6644 measured reflections
3469 independent reflections
2412 reflections with I > 2σ(I)
R_int = 0.049

Refinement

R[F² > 2σ(F²)] = 0.088
wR(F²) = 0.203
S = 1.11
3469 reflections
199 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

Cg2 is the centroid of the C7–C12 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯N2ⁱ	0.86	2.22	3.054 (14)	162
C8—H8⋯O1ⁱ	0.93	2.43	3.334 (14)	164
C14—H14A⋯Cg2ⁱⁱ	0.97	2.66	3.523 (18)	149
Symmetry codes: (i) -x-1, -y+2, -z+2; (ii) x+1, y, z.

Data collection: CrystalClear (Rigaku, 2007 ); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEX (McArdle, 1995 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681001024X/si2244sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681001024X/si2244Isup2.hkl

checkCIF report

Comment top

Benzothiazole is an important moiety used in drug development because of its biological activities. A number of benzothiazole derivatives were shown to have anti-tumor (Brantley et al., 2004; Mortimer et al., 2006; Ćaleta et al., 2009) or anti-microbial activities (Palmer et al., 1971). During our development of 2-aminobenzothiazole-based Urokinase-Type Plasminogen Activator (uPA) inhibitors, we synthesized the title compound as an intermediate while its activity was not tested because it is only a fragment of our target molecule.

The molecular structure of the compound is shown in Fig. 1. The benzothiazole moiety in this structure is very similar to other benzothiazole compounds reported before (Lynch, 2002; Matković-Čalogović et al., 2003). The dihedral angle between the carbonylamino group and the planar central 9-membered ring system is 7.59 (6) °, and between the central rings and the ethylcarboxylate group is 7.72 (6) °, respectively.

The packing of molecules is shown in Fig. 2. Molecules form pairs via N—H···N and C—H···O hydrogen bonds over crystallographic inversion symmetry. π—π stacking and C14—H14A···Cg2 hydrogen bonds (Cg2 is the benzene ring centroid) link pairs in a stacking column. In the π—π packing, Cg1···Cg1ⁱⁱⁱ is 3.790 (2) Å (Cg1 is the thiazole ring centroid and symmetry code iii = -x, 2-y, 2-z), the plane to plane distance of the two thiazole rings is 3.382 Å with an offset of 1.711 Å, Cg1···Cg2ⁱⁱⁱ is 3.845 (2) Å, the perpendicular distances of Cg1 to benzene ring is 3.369 Å, and Cg2 to thiazole ring is 3.383 Å. The hydrogen bonds are listed in Table 1, and the stacking geometries calculated with PLATON (Spek, 2009).

Related literature top

For benzothiazole derivatives with anti-tumor activity, see: Brantley et al. (2004); Ćaleta et al. (2009); Mortimer et al. (2006) and for anti-tuberculous benzothiazolines, see: Palmer et al. (1971). For related benzothiazole structures, see: Lynch et al. (2002); Matković-Čalogović et al. (2003).

Experimental top

Di-tert-butyl dicarbonate (4.92 g, 22.5 mmol) and 4-dimethylamino pyridine (2.06 g, 16.9 mmol) were added to a solution of ethyl 2-aminebenzothiazole-6-carboxylate (the starting compound) (2.5 g, 11.3 mmol) in dry THF (300 ml), and stirred for 22 hours at room temperature. Then the solvent THF was evaporated, and the residue was extracted with 1 liter of dichloromethane. The dichloromethane washed with 1 N aq HCl, water, and brine, sequentially, and dried with Na₂SO₄. Further filtration and concentration yielded the dried compound as a yellow solid [2.61 g, yield: 72%]. The solid was dissolved in DMF and filtered. The DMF was evaporated slowly at room temperature for a week, giving colorless needle crystals.

Computing details top

Data collection: CrystalClear (Rigaku, 2007); cell refinement: CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are shown at the 50% probability level. Hydrogen atoms are shown as spheres of arbitrary radii.
	Fig. 2. The packing diagram for the title compound. All hydrogen atoms have been omitted for clarity. Hydrogen bonds are indicated by dashed lines.

Ethyl 2-(tert-butoxycarbonylamino)-1,3-benzothiazole-6-carboxylate top

Crystal data top

C₁₅H₁₈N₂O₄S	Z = 2
M_r = 322.37	F(000) = 340
Triclinic, P1	D_x = 1.355 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.3026 (13) Å	Cell parameters from 2354 reflections
b = 10.791 (2) Å	θ = 12–18°
c = 11.909 (2) Å	µ = 0.22 mm⁻¹
α = 80.58 (3)°	T = 293 K
β = 86.61 (3)°	Needle, colorless
γ = 81.57 (3)°	0.70 × 0.05 × 0.02 mm
V = 789.9 (3) Å³

Data collection top

Rigaku Saturn 724 CCD area-detector diffractometer	3469 independent reflections
Radiation source: fine-focus sealed tube	2412 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.049
Detector resolution: 28.5714 pixels mm^-1	θ_max = 27.5°, θ_min = 3.3°
dtprofit.ref scans	h = −7→8
Absorption correction: numerical (NUMABS; Higashi, 2000)	k = −13→11
T_min = 0.987, T_max = 0.995	l = −15→15
6644 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.088	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.203	H-atom parameters constrained
S = 1.11	w = 1/[σ²(F_o²) + (0.0613P)² + 0.839P] where P = (F_o² + 2F_c²)/3
3469 reflections	(Δ/σ)_max < 0.001
199 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.30 e Å⁻³

Crystal data top

C₁₅H₁₈N₂O₄S	γ = 81.57 (3)°
M_r = 322.37	V = 789.9 (3) Å³
Triclinic, P1	Z = 2
a = 6.3026 (13) Å	Mo Kα radiation
b = 10.791 (2) Å	µ = 0.22 mm⁻¹
c = 11.909 (2) Å	T = 293 K
α = 80.58 (3)°	0.70 × 0.05 × 0.02 mm
β = 86.61 (3)°

Data collection top

Rigaku Saturn 724 CCD area-detector diffractometer	3469 independent reflections
Absorption correction: numerical (NUMABS; Higashi, 2000)	2412 reflections with I > 2σ(I)
T_min = 0.987, T_max = 0.995	R_int = 0.049
6644 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.088	0 restraints
wR(F²) = 0.203	H-atom parameters constrained
S = 1.11	Δρ_max = 0.26 e Å⁻³
3469 reflections	Δρ_min = −0.30 e Å⁻³
199 parameters

Special details top

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.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
S1	−0.00627 (16)	0.75048 (10)	0.94306 (9)	0.0535 (3)
O1	−0.5534 (4)	0.6760 (2)	1.1764 (2)	0.0535 (7)
N1	−0.4017 (5)	0.8086 (3)	1.0445 (3)	0.0463 (7)
H1	−0.5187	0.8593	1.0515	0.056*
O4	0.6440 (4)	0.9028 (3)	0.6602 (2)	0.0544 (7)
N2	−0.2502 (5)	0.9692 (3)	0.9263 (2)	0.0425 (7)
O2	−0.2352 (5)	0.6079 (3)	1.0923 (3)	0.0736 (10)
O3	0.5621 (5)	1.1131 (3)	0.6102 (3)	0.0702 (9)
C1	−0.6011 (11)	0.4579 (5)	1.1729 (5)	0.101 (2)
H1A	−0.6143	0.3772	1.2185	0.151*
H1B	−0.4776	0.4496	1.1221	0.151*
H1C	−0.7275	0.4866	1.1295	0.151*
C2	−0.3890 (9)	0.5131 (6)	1.3253 (5)	0.113 (2)
H2A	−0.4042	0.4330	1.3717	0.169*
H2B	−0.3848	0.5759	1.3733	0.169*
H2C	−0.2583	0.5050	1.2798	0.169*
C3	−0.7806 (8)	0.5823 (5)	1.3176 (5)	0.0844 (17)
H3A	−0.8094	0.5075	1.3685	0.127*
H3B	−0.8973	0.6104	1.2671	0.127*
H3C	−0.7654	0.6480	1.3608	0.127*
C4	−0.5758 (7)	0.5525 (4)	1.2490 (4)	0.0599 (11)
C5	−0.3848 (6)	0.6882 (4)	1.1045 (3)	0.0497 (9)
C6	−0.2382 (6)	0.8519 (4)	0.9732 (3)	0.0426 (8)
C7	−0.0652 (5)	0.9890 (3)	0.8612 (3)	0.0410 (8)
C8	−0.0223 (6)	1.1047 (4)	0.7995 (3)	0.0483 (9)
H8	−0.1213	1.1775	0.8004	0.058*
C9	0.1687 (6)	1.1096 (4)	0.7373 (3)	0.0506 (9)
H9	0.1980	1.1866	0.6962	0.061*
C10	0.3196 (5)	1.0007 (4)	0.7350 (3)	0.0448 (9)
C11	0.2781 (6)	0.8856 (4)	0.7956 (3)	0.0479 (9)
H11	0.3769	0.8129	0.7938	0.057*
C12	0.0869 (6)	0.8803 (3)	0.8590 (3)	0.0438 (8)
C13	0.5180 (6)	1.0144 (4)	0.6628 (3)	0.0500 (9)
C14	0.8351 (6)	0.9081 (4)	0.5871 (3)	0.0554 (10)
H14A	0.9345	0.9534	0.6178	0.066*
H14B	0.7982	0.9520	0.5116	0.066*
C15	0.9356 (9)	0.7748 (5)	0.5812 (5)	0.0817 (15)
H15A	1.0624	0.7757	0.5324	0.123*
H15B	0.8357	0.7307	0.5512	0.123*
H15C	0.9734	0.7326	0.6561	0.123*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0453 (6)	0.0497 (6)	0.0608 (6)	−0.0027 (4)	0.0103 (4)	−0.0027 (5)
O1	0.0468 (15)	0.0474 (15)	0.0610 (17)	−0.0030 (12)	0.0131 (13)	−0.0014 (13)
N1	0.0382 (16)	0.0485 (18)	0.0490 (18)	−0.0047 (13)	0.0040 (14)	−0.0009 (14)
O4	0.0382 (14)	0.0655 (18)	0.0594 (17)	−0.0122 (13)	0.0127 (12)	−0.0099 (14)
N2	0.0373 (16)	0.0482 (18)	0.0424 (16)	−0.0074 (13)	−0.0003 (13)	−0.0073 (14)
O2	0.0594 (19)	0.0573 (18)	0.090 (2)	0.0079 (15)	0.0272 (17)	0.0049 (16)
O3	0.0549 (18)	0.065 (2)	0.085 (2)	−0.0168 (15)	0.0138 (16)	0.0076 (17)
C1	0.128 (5)	0.060 (3)	0.113 (5)	−0.028 (3)	0.036 (4)	−0.013 (3)
C2	0.071 (4)	0.144 (6)	0.099 (4)	−0.015 (4)	−0.011 (3)	0.057 (4)
C3	0.072 (3)	0.070 (3)	0.097 (4)	−0.010 (2)	0.040 (3)	0.013 (3)
C4	0.054 (2)	0.049 (2)	0.071 (3)	−0.0094 (19)	0.010 (2)	0.008 (2)
C5	0.040 (2)	0.051 (2)	0.056 (2)	−0.0070 (17)	0.0093 (18)	−0.0075 (19)
C6	0.0377 (18)	0.049 (2)	0.0417 (19)	−0.0057 (15)	−0.0012 (15)	−0.0082 (16)
C7	0.0324 (17)	0.047 (2)	0.0438 (19)	−0.0050 (15)	−0.0003 (15)	−0.0094 (16)
C8	0.0395 (19)	0.046 (2)	0.059 (2)	−0.0067 (16)	0.0004 (17)	−0.0060 (18)
C9	0.045 (2)	0.052 (2)	0.055 (2)	−0.0145 (17)	0.0038 (18)	−0.0057 (19)
C10	0.0319 (18)	0.055 (2)	0.049 (2)	−0.0094 (16)	0.0022 (15)	−0.0106 (18)
C11	0.0381 (19)	0.053 (2)	0.050 (2)	−0.0017 (16)	0.0021 (16)	−0.0076 (18)
C12	0.0391 (19)	0.051 (2)	0.0417 (19)	−0.0065 (16)	0.0012 (15)	−0.0077 (16)
C13	0.0357 (19)	0.063 (3)	0.051 (2)	−0.0116 (18)	−0.0027 (16)	−0.0047 (19)
C14	0.042 (2)	0.073 (3)	0.052 (2)	−0.0156 (19)	0.0139 (18)	−0.012 (2)
C15	0.078 (3)	0.081 (3)	0.084 (4)	−0.008 (3)	0.027 (3)	−0.020 (3)

Geometric parameters (Å, º) top

S1—C12	1.738 (4)	C3—C4	1.509 (6)
S1—C6	1.750 (4)	C3—H3A	0.9600
O1—C5	1.332 (4)	C3—H3B	0.9600
O1—C4	1.486 (5)	C3—H3C	0.9600
N1—C5	1.369 (5)	C7—C8	1.396 (5)
N1—C6	1.382 (5)	C7—C12	1.404 (5)
N1—H1	0.8600	C8—C9	1.379 (5)
O4—C13	1.345 (5)	C8—H8	0.9300
O4—C14	1.446 (4)	C9—C10	1.402 (5)
N2—C6	1.290 (4)	C9—H9	0.9300
N2—C7	1.385 (4)	C10—C11	1.382 (5)
O2—C5	1.203 (5)	C10—C13	1.487 (5)
O3—C13	1.205 (4)	C11—C12	1.388 (5)
C1—C4	1.501 (7)	C11—H11	0.9300
C1—H1A	0.9600	C14—C15	1.495 (6)
C1—H1B	0.9600	C14—H14A	0.9700
C1—H1C	0.9600	C14—H14B	0.9700
C2—C4	1.499 (7)	C15—H15A	0.9600
C2—H2A	0.9600	C15—H15B	0.9600
C2—H2B	0.9600	C15—H15C	0.9600
C2—H2C	0.9600

C12—S1—C6	87.89 (18)	N2—C6—S1	117.2 (3)
C5—O1—C4	120.7 (3)	N1—C6—S1	121.5 (3)
C5—N1—C6	122.6 (3)	N2—C7—C8	125.6 (3)
C5—N1—H1	118.7	N2—C7—C12	114.9 (3)
C6—N1—H1	118.7	C8—C7—C12	119.5 (3)
C13—O4—C14	115.5 (3)	C9—C8—C7	119.1 (4)
C6—N2—C7	110.1 (3)	C9—C8—H8	120.4
C4—C1—H1A	109.5	C7—C8—H8	120.4
C4—C1—H1B	109.5	C8—C9—C10	121.2 (4)
H1A—C1—H1B	109.5	C8—C9—H9	119.4
C4—C1—H1C	109.5	C10—C9—H9	119.4
H1A—C1—H1C	109.5	C11—C10—C9	120.1 (3)
H1B—C1—H1C	109.5	C11—C10—C13	122.5 (3)
C4—C2—H2A	109.5	C9—C10—C13	117.3 (3)
C4—C2—H2B	109.5	C10—C11—C12	119.0 (4)
H2A—C2—H2B	109.5	C10—C11—H11	120.5
C4—C2—H2C	109.5	C12—C11—H11	120.5
H2A—C2—H2C	109.5	C11—C12—C7	121.2 (3)
H2B—C2—H2C	109.5	C11—C12—S1	128.9 (3)
C4—C3—H3A	109.5	C7—C12—S1	109.9 (3)
C4—C3—H3B	109.5	O3—C13—O4	122.8 (4)
H3A—C3—H3B	109.5	O3—C13—C10	124.7 (4)
C4—C3—H3C	109.5	O4—C13—C10	112.5 (3)
H3A—C3—H3C	109.5	O4—C14—C15	107.8 (3)
H3B—C3—H3C	109.5	O4—C14—H14A	110.1
O1—C4—C2	109.9 (4)	C15—C14—H14A	110.1
O1—C4—C1	108.4 (4)	O4—C14—H14B	110.1
C2—C4—C1	113.7 (5)	C15—C14—H14B	110.1
O1—C4—C3	102.9 (3)	H14A—C14—H14B	108.5
C2—C4—C3	110.7 (5)	C14—C15—H15A	109.5
C1—C4—C3	110.7 (4)	C14—C15—H15B	109.5
O2—C5—O1	126.7 (4)	H15A—C15—H15B	109.5
O2—C5—N1	123.0 (3)	C14—C15—H15C	109.5
O1—C5—N1	110.3 (3)	H15A—C15—H15C	109.5
N2—C6—N1	121.3 (3)	H15B—C15—H15C	109.5

Hydrogen-bond geometry (Å, º) top

Cg2 is the centroid of the C7–C12 benzene ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N2ⁱ	0.86	2.22	3.054 (14)	162
C8—H8···O1ⁱ	0.93	2.43	3.334 (14)	164
C14—H14A···Cg2ⁱⁱ	0.97	2.66	3.523 (18)	149

Symmetry codes: (i) −x−1, −y+2, −z+2; (ii) x+1, y, z.

Experimental details

Crystal data
Chemical formula	C₁₅H₁₈N₂O₄S
M_r	322.37
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	6.3026 (13), 10.791 (2), 11.909 (2)
α, β, γ (°)	80.58 (3), 86.61 (3), 81.57 (3)
V (Å³)	789.9 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.22
Crystal size (mm)	0.70 × 0.05 × 0.02

Data collection
Diffractometer	Rigaku Saturn 724 CCD area-detector diffractometer
Absorption correction	Numerical (NUMABS; Higashi, 2000)
T_min, T_max	0.987, 0.995
No. of measured, independent and observed [I > 2σ(I)] reflections	6644, 3469, 2412
R_int	0.049
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.088, 0.203, 1.11
No. of reflections	3469
No. of parameters	199
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.30

Computer programs: CrystalClear (Rigaku, 2007), SHELXS97 (Sheldrick, 2008), ORTEX (McArdle, 1995), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

Cg2 is the centroid of the C7–C12 benzene ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N2ⁱ	0.86	2.22	3.054 (14)	162.4
C8—H8···O1ⁱ	0.93	2.43	3.334 (14)	163.8
C14—H14A···Cg2ⁱⁱ	0.97	2.66	3.523 (18)	148.5

Symmetry codes: (i) −x−1, −y+2, −z+2; (ii) x+1, y, z.

Acknowledgements

The authors gratefully acknowledge the financial support from Fujian Institute of Research on the Structure of Matter, State Key Laboratory of Structural Chemistry, Chinese Academy of Sciences (Nos. SZD08003 and NSFC30811130467). Fujian Natural Science Foundation (No. 2008 J0330) and Fujian Terms of Science and Technology (Nos. 2008 F5033, 2008 J1005 and 2009I0016).

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