tert-Butyl 6-bromo-1,4-dimethyl-9H-carbazole-9-carboxyl-ate.

The title compound, C(19)H(20)BrNO(2), consists of a carbazole skeleton with methyl groups at positions 1 and 4, a protecting group located at the N atom and a Br atom at position 6. The pyrrole ring is oriented at dihedral angles of 1.27 (7) and 4.86 (7)° with respect to the adjacent benzene rings. The dihedral angle between the benzene rings is 5.11 (7). The crystal structure is determined mainly by intra-molecular C-H⋯O and inter-molecular π-π inter-actions. π-stacking between adjacent molecules forms columns with a parallel arrangement of the carbazole ring systems. The presence of the tert-but-oxy-carbonyl group on the carbazole N atom and the intra-molecular hydrogen bond induce a particular conformation of the exocyclic N-C bond within the mol-ecule.

Related literature

For the pharmaceutical properties of carbazole derivatives, see: Itoigawa et al. (2000 ▶); Laronze et al. (2005 ▶); Thevissen et al. (2009 ▶). For their electroactivity and luminescent properties, see: Grazulevicius et al. (2003 ▶) and for their their applications in the light-emitting field, see: Zhang et al. (2006 ▶). For the synthesis of carbazoles and ellipticine derivatives, see: Ergün et al. (1998 ▶); Knölker et al. (2002 ▶); Liu et al. (2007 ▶). For related structures, see: Caruso et al. (2007 ▶); Sopková-de Oliveira Santos et al. (2008 ▶). For bond-length data, see: Allen et al. (1987 ▶). The title compound constitutes a cheap and reactive inter­mediate for the preparation of new analogs of the anti­cancer agent 9-meth­oxy­ellipticine, see: Le Pecq et al. (1974 ▶). A lengthening of N—C bond lengths due to the presence of a protecting group has been observed in similar compounds, see: Back et al. (2001 ▶); Chakkaravarthi et al. (2009 ▶); Terpin et al. (1998 ▶) For N-sulfonyl carbazole derivatives with similar conformations, see: Chakkaravarthi et al. (2008 ▶). For non N-atom-substituted analogs, see: Viossat et al. (1988 ▶).

Experimental

Crystal data

C19H20BrNO2

M = 374.27

Triclinic,

a = 7.521 (4) Å

b = 9.715 (5) Å

c = 11.930 (6) Å

α = 91.10 (4)°

β = 96.40 (4)°

γ = 90.96 (4)°

V = 865.9 (8) Å3

Z = 2

Mo Kα radiation

μ = 2.38 mm−1

T = 291 K

0.46 × 0.37 × 0.34 mm

Data collection

Bruker–Nonius APEXII KappaCCD diffractometer

Absorption correction: numerical (SAINT; Bruker, 2007 ▶) T min = 0.378, T max = 0.429

37091 measured reflections

5718 independent reflections

4268 reflections with I > 2σ(I)

R int = 0.025

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.092

S = 1.02

5718 reflections

213 parameters

H-atom parameters constrained

Δρmax = 0.63 e Å−3

Δρmin = −0.52 e Å−3

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810026528/om2338sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810026528/om2338Isup2.hkl

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

C19H20BrNO2	Z = 2
Mr = 374.27	F(000) = 384
Triclinic, P1	Dx = 1.435 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.521 (4) Å	Cell parameters from 9940 reflections
b = 9.715 (5) Å	θ = 5.4–57.6°
c = 11.930 (6) Å	µ = 2.38 mm−1
α = 91.10 (4)°	T = 291 K
β = 96.40 (4)°	Block, colorless
γ = 90.96 (4)°	0.46 × 0.37 × 0.34 mm
V = 865.9 (8) Å3

Bruker–Nonius APEXII Kappa CCD diffractometer	5718 independent reflections
Radiation source: fine-focus sealed tube	4268 reflections with I > 2σ(I)
graphite	Rint = 0.025
φ and ω scans	θmax = 31.5°, θmin = 2.1°
Absorption correction: numerical (SAINT; Bruker, 2007)	h = −11→11
Tmin = 0.378, Tmax = 0.429	k = −14→14
37091 measured reflections	l = −17→17

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092	H-atom parameters constrained
S = 1.02	w = 1/[σ2(Fo2) + (0.0409P)2 + 0.2555P] where P = (Fo2 + 2Fc2)/3
5718 reflections	(Δ/σ)max = 0.001
213 parameters	Δρmax = 0.63 e Å−3
0 restraints	Δρmin = −0.52 e Å−3

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.

	x	y	z	Uiso*/Ueq
C1	0.3387 (2)	−0.20146 (16)	0.34933 (15)	0.0458 (3)
C2	0.3632 (2)	−0.30773 (17)	0.42578 (17)	0.0542 (4)
H2	0.3978	−0.3929	0.3996	0.065*
C3	0.3389 (2)	−0.29340 (17)	0.53845 (17)	0.0543 (4)
H3	0.3563	−0.3690	0.5847	0.065*
C4	0.2894 (2)	−0.16985 (16)	0.58456 (14)	0.0444 (3)
C4A	0.26189 (18)	−0.06062 (15)	0.51011 (13)	0.0376 (3)
C5	0.1845 (2)	0.15877 (16)	0.62353 (12)	0.0411 (3)
H5	0.1796	0.1170	0.6927	0.049*
C5A	0.22209 (18)	0.08324 (14)	0.52870 (12)	0.0360 (3)
C6	0.1549 (2)	0.29736 (16)	0.61113 (13)	0.0437 (3)
C7	0.1590 (2)	0.36264 (16)	0.50904 (14)	0.0466 (3)
H7	0.1388	0.4567	0.5046	0.056*
C8	0.1928 (2)	0.28895 (16)	0.41425 (14)	0.0455 (3)
H8	0.1944	0.3315	0.3452	0.055*
C8A	0.22440 (19)	0.14932 (15)	0.42488 (12)	0.0377 (3)
C9	0.2702 (3)	−0.1553 (2)	0.70822 (16)	0.0585 (4)
H9A	0.3533	−0.0863	0.7419	0.088*
H9B	0.2945	−0.2417	0.7440	0.088*
H9C	0.1504	−0.1286	0.7178	0.088*
C9A	0.28247 (18)	−0.07791 (15)	0.39496 (13)	0.0383 (3)
C10	0.3831 (3)	−0.2220 (2)	0.23079 (17)	0.0601 (4)
H10A	0.4583	−0.3004	0.2270	0.090*
H10B	0.4447	−0.1415	0.2083	0.090*
H10C	0.2747	−0.2370	0.1812	0.090*
C11	0.2066 (2)	0.06842 (17)	0.22633 (13)	0.0455 (3)
C12	0.2220 (3)	0.2419 (2)	0.08037 (15)	0.0595 (4)
C13	0.3005 (4)	0.1472 (3)	−0.00242 (19)	0.0880 (8)
H13A	0.2410	0.0588	−0.0042	0.132*
H13B	0.4259	0.1367	0.0206	0.132*
H13C	0.2845	0.1858	−0.0762	0.132*
C14	0.0229 (3)	0.2543 (3)	0.05422 (19)	0.0749 (6)
H14A	−0.0326	0.1646	0.0537	0.112*
H14B	−0.0037	0.2946	−0.0184	0.112*
H14C	−0.0221	0.3116	0.1107	0.112*
C15	0.3132 (5)	0.3824 (3)	0.0885 (2)	0.0956 (9)
H15A	0.2879	0.4284	0.0181	0.143*
H15B	0.4401	0.3719	0.1047	0.143*
H15C	0.2695	0.4360	0.1477	0.143*
Br1	0.10889 (3)	0.40593 (2)	0.738576 (16)	0.06549 (9)
O1	0.12304 (19)	−0.01560 (14)	0.16710 (11)	0.0611 (3)
O2	0.26615 (18)	0.19081 (13)	0.19661 (10)	0.0537 (3)
N9	0.25825 (17)	0.05083 (13)	0.34212 (10)	0.0408 (3)

	U11	U22	U33	U12	U13	U23
C1	0.0374 (7)	0.0426 (7)	0.0575 (9)	0.0008 (6)	0.0074 (6)	−0.0080 (7)
C2	0.0496 (9)	0.0381 (8)	0.0750 (12)	0.0043 (7)	0.0072 (8)	−0.0050 (7)
C3	0.0532 (9)	0.0395 (8)	0.0700 (11)	0.0029 (7)	0.0048 (8)	0.0088 (7)
C4	0.0380 (7)	0.0428 (7)	0.0521 (8)	−0.0002 (6)	0.0034 (6)	0.0072 (6)
C4A	0.0305 (6)	0.0376 (7)	0.0448 (7)	0.0003 (5)	0.0040 (5)	0.0011 (5)
C5	0.0416 (7)	0.0454 (8)	0.0365 (7)	0.0035 (6)	0.0048 (6)	0.0014 (6)
C5A	0.0312 (6)	0.0383 (7)	0.0386 (7)	0.0023 (5)	0.0030 (5)	0.0015 (5)
C6	0.0435 (8)	0.0458 (8)	0.0418 (7)	0.0071 (6)	0.0044 (6)	−0.0055 (6)
C7	0.0504 (9)	0.0386 (7)	0.0507 (8)	0.0091 (6)	0.0041 (7)	−0.0004 (6)
C8	0.0534 (9)	0.0422 (7)	0.0410 (7)	0.0075 (6)	0.0042 (6)	0.0049 (6)
C8A	0.0359 (7)	0.0395 (7)	0.0376 (6)	0.0027 (5)	0.0032 (5)	−0.0010 (5)
C9	0.0647 (11)	0.0576 (10)	0.0540 (10)	0.0060 (8)	0.0070 (8)	0.0172 (8)
C9A	0.0324 (6)	0.0377 (7)	0.0446 (7)	−0.0002 (5)	0.0044 (5)	−0.0006 (5)
C10	0.0612 (11)	0.0584 (10)	0.0620 (11)	0.0077 (8)	0.0145 (8)	−0.0156 (8)
C11	0.0471 (8)	0.0499 (8)	0.0400 (7)	0.0040 (7)	0.0068 (6)	−0.0013 (6)
C12	0.0760 (12)	0.0653 (11)	0.0388 (8)	0.0052 (9)	0.0114 (8)	0.0088 (7)
C13	0.110 (2)	0.109 (2)	0.0513 (11)	0.0309 (16)	0.0346 (12)	0.0106 (12)
C14	0.0836 (15)	0.0850 (15)	0.0567 (11)	0.0204 (12)	0.0062 (10)	0.0129 (11)
C15	0.129 (2)	0.0829 (17)	0.0745 (16)	−0.0223 (16)	0.0062 (15)	0.0314 (13)
Br1	0.08728 (16)	0.05996 (12)	0.05042 (11)	0.01706 (10)	0.01285 (9)	−0.01170 (8)
O1	0.0717 (8)	0.0602 (8)	0.0484 (7)	−0.0039 (6)	−0.0046 (6)	−0.0062 (6)
O2	0.0680 (8)	0.0550 (7)	0.0382 (5)	−0.0045 (6)	0.0059 (5)	0.0051 (5)
N9	0.0451 (7)	0.0402 (6)	0.0374 (6)	0.0032 (5)	0.0056 (5)	−0.0012 (5)

C1—C2	1.392 (3)	C9—H9C	0.9600
C1—C9A	1.399 (2)	C9A—N9	1.417 (2)
C1—C10	1.499 (3)	C10—H10A	0.9600
C2—C3	1.381 (3)	C10—H10B	0.9600
C2—H2	0.9300	C10—H10C	0.9600
C3—H3	0.9300	C11—O1	1.193 (2)
C4—C3	1.384 (3)	C11—O2	1.332 (2)
C4—C4A	1.400 (2)	C11—N9	1.407 (2)
C4—C9	1.502 (3)	C12—O2	1.486 (2)
C4A—C9A	1.407 (2)	C12—C13	1.511 (3)
C5—C5A	1.394 (2)	C12—C15	1.514 (3)
C5—H5	0.9300	C13—H13A	0.9600
C5A—C8A	1.408 (2)	C13—H13B	0.9600
C5A—C4A	1.452 (2)	C13—H13C	0.9600
C6—C5	1.376 (2)	C14—C12	1.502 (3)
C6—C7	1.387 (2)	C14—H14A	0.9600
C7—C8	1.377 (2)	C14—H14B	0.9600
C7—H7	0.9300	C14—H14C	0.9600
C8—C8A	1.387 (2)	C15—H15A	0.9600
C8—H8	0.9300	C15—H15B	0.9600
C8A—N9	1.408 (2)	C15—H15C	0.9600
C9—H9A	0.9600	Br1—C6	1.9004 (18)
C9—H9B	0.9600
C1—C2—H2	118.3	C8A—N9—C9A	108.07 (12)
C1—C9A—C4A	122.57 (15)	C9A—C1—C10	125.22 (16)
C1—C9A—N9	128.35 (14)	C9A—C4A—C5A	107.15 (13)
C1—C10—H10A	109.5	H9A—C9—H9B	109.5
C1—C10—H10B	109.5	H9A—C9—H9C	109.5
C1—C10—H10C	109.5	H9B—C9—H9C	109.5
C2—C1—C9A	114.58 (16)	H10A—C10—H10B	109.5
C2—C1—C10	120.08 (16)	H10A—C10—H10C	109.5
C2—C3—C4	122.00 (17)	H10B—C10—H10C	109.5
C2—C3—H3	119.0	C11—O2—C12	121.26 (14)
C3—C2—C1	123.47 (16)	C11—N9—C8A	122.65 (13)
C3—C2—H2	118.3	C11—N9—C9A	125.02 (13)
C3—C4—C4A	116.27 (16)	C12—C13—H13A	109.5
C3—C4—C9	121.07 (16)	C12—C13—H13B	109.5
C4—C3—H3	119.0	C12—C13—H13C	109.5
C4—C4A—C9A	121.03 (14)	C12—C14—H14A	109.5
C4—C4A—C5A	131.72 (15)	C12—C14—H14B	109.5
C4—C9—H9A	109.5	C12—C14—H14C	109.5
C4—C9—H9B	109.5	C12—C15—H15A	109.5
C4—C9—H9C	109.5	C12—C15—H15B	109.5
C4A—C4—C9	122.65 (16)	C12—C15—H15C	109.5
C4A—C9A—N9	108.67 (13)	C13—C12—C15	111.9 (2)
C5—C5A—C8A	119.61 (14)	H13A—C13—H13C	109.5
C5—C5A—C4A	133.06 (14)	H13B—C13—H13C	109.5
C5—C6—C7	122.74 (14)	H13A—C13—H13B	109.5
C5—C6—Br1	119.29 (12)	C14—C12—C13	112.2 (2)
C5A—C5—H5	121.2	C14—C12—C15	110.9 (2)
C5A—C8A—N9	108.75 (13)	H14A—C14—H14B	109.5
C6—C5—C5A	117.59 (14)	H14A—C14—H14C	109.5
C6—C5—H5	121.2	H14B—C14—H14C	109.5
C6—C7—H7	119.8	H15A—C15—H15C	109.5
C7—C6—Br1	117.97 (12)	H15A—C15—H15B	109.5
C7—C8—C8A	117.97 (15)	H15B—C15—H15C	109.5
C7—C8—H8	121.0	O1—C11—O2	127.27 (16)
C8—C7—C6	120.33 (15)	O1—C11—N9	123.67 (16)
C8—C7—H7	119.8	O2—C11—N9	109.06 (14)
C8—C8A—C5A	121.75 (14)	O2—C12—C14	110.07 (16)
C8—C8A—N9	129.48 (14)	O2—C12—C13	109.40 (17)
C8A—C5A—C4A	107.33 (13)	O2—C12—C15	101.86 (17)
C8A—C8—H8	121.0
C1—C9A—N9—C11	30.8 (2)	C8A—N9—C11—O1	−128.47 (18)
C8—C8A—N9—C11	−22.4 (2)	C9A—C4A—C4—C9	179.52 (15)
C9A—N9—C11—O2	−154.38 (14)	C2—C3—C4—C9	−177.79 (17)
C9A—N9—C11—O1	25.5 (3)	C3—C2—C1—C10	174.71 (17)
C8A—N9—C11—O2	51.6 (2)	C4A—C9A—C1—C10	−172.72 (15)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···O2	0.93	2.33	2.863 (3)	116

Group 1/group 2	ccd	sa	ipd
Cg2/Cg3i	3.755 (2)	24	3.532 (1)
Cg3/Cg2i	3.755 (2)	20	3.433 (1)
Cg1/Cg1i	3.927 (2)	22	3.638 (1)
Cg2/Cg3ii	3.811 (2)	18	3.654 (1)
Cg3/Cg2ii	3.811 (2)	16	3.626 (1)
Cg1/Cg1ii	4.199 (2)	32	3.578 (1)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8⋯O2	0.93	2.33	2.863 (3)	116

Table 2

π–π inter­actions (Å, °)

Cg1, Cg2 and Cg3 are the centroids of the N9–C9A–C4A–C5A–C8A, C9A–C1–C2–C3–C4–C4A and C5A–C5–C6–C7–C8–C8A rings, respectively, ccd is the distance between ring centroids, sa is the mean slippage angle (angle subtended by the inter­centroid vector to the plane normal) and ipd is the mean inter­planar distance (distance from one plane to the neighbouring centroid). For details, see Janiak (2000 ▶).

Group 1/group 2	ccd	sa	ipd
Cg2/Cg3i	3.755 (2)	24	3.532 (1)
Cg3/Cg2i	3.755 (2)	20	3.433 (1)
Cg1/Cg1i	3.927 (2)	22	3.638 (1)
Cg2/Cg3ii	3.811 (2)	18	3.654 (1)
Cg3/Cg2ii	3.811 (2)	16	3.626 (1)
Cg1/Cg1ii	4.199 (2)	32	3.578 (1)

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