1-Hydr­oxy-3-methyl-9H-carbazole-2-carbaldehyde

The carbazole unit of the title mol­ecule, C₁₄H₁₁NO₂, is planar. The hydr­oxy group at position 1, carbaldehyde group at position 2, and methyl group at position 3 (with the exception of two H atoms) are coplanar with the attached benzene ring. The dihedral angle between the two benzene rings is 3.57 (8)°. The pyrrole ring makes dihedral angles of 1.53 (9) and 2.06 (9)° with the unsubstituted and substituted benzene rings, respectively. The structure is stabilized by inter- and intra­molecular N—H...O and O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 160 K
• Mean [sigma](C-C)= 0.003 Å
• R factor = 0.053
• wR factor = 0.148
• Data-to-parameter ratio = 14.4

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S1. Comment

Carbazoles are ubiquitous structural subunits of numerous naturally occurring compounds as well as synthetic materials. Over the past four decades, a wide range of biologically active carbazole alkaloids have been isolated from plant sources. Among the ten naturally occurring simple carbazole alkaloids, five have oxygen function at C1 (or its equivalent C8) and most of them are having substituents in the third position (Chakraborty, 1977; Chakraborty & Roy, 1991). Many of these natural products display biological properties such as antitumor (Saturnino et al., 2003; Borek-Dohalska et al., 2004; Hagg et al., 2004; Hedin et al., 2000), anti-HIV properties (Hirata et al., 1999; Wang et al., 2005), psychotropic, anti-inflammatory, antihistaminic, antibiotic and antioxidative activities (Knolker et al., 2002). As synthetic materials many carbazoles exhibit photo-reactive, photoconductive and light-emitting properties (Van Dijken et al., 2004; Thomas et al., 2001). Carbazoles have also been recognized as a useful scaffold in anion binding studies (Chmielewski et al., 2004). Here we report the crystal structure of 1-hydroxy-3-methyl-9H- carbazole-2-carbaldehyde, (I).

The carbazole unit of the title molecule, (I), (Fig. 1), is planar. The attached hydroxy group at position 1, carbaldehyde group at position 2, and methyl group at position 3 have coplanar orientations with the benzene ring. The dihedral angle between the two benzene rings is 3.57 (8)°. The pyrrole ring makes a dihedral angles of 1.53 (9)° and 2.06 (9)° with the unsubstituted and substituted benzene respectively. The structure is stabilized by inter- and intramolecular N9–H9···O1(-x,1 - y,-z) and O1–H1···O21 hydrogen bonds respectively as shown in Fig. 2 and Fig. 3.

Related literature

For related literature, see: Borek-Dohalska et al. (2004); Chakraborty (1977); Chakraborty & Roy (1991); Chmielewski et al. (2004); Hagg et al. (2004); Hedin et al. (2000); Hirata et al. (1999); Knolker & Reddy (2002); Saturnino et al. (2003); Thomas et al. (2001); Van Dijken et al. (2004); Wang et al. (2005).

S2. Experimental

30% Sodium hydride in mineral oil (2.4 g) was washed with dry benzene and taken in a round bottomed flask containing dry benzene (100 ml). The flask was kept in an ice bath with stirring. Ethyl formate (8 ml) was added drop wise over the period of 10 minutes to the solution. Then 3-methyl-2,3,4,9-tetrahydro-1H- carbazol-1-one (1.6 g, 0.008 mol) in dry benzene (25 ml) was added slowly and the reaction mixture was allowed to stir for another 36 h. The reaction was monitored by TLC. After the completion of the reaction the benzene was removed and the contents in the flask were transferred to a beaker containing water. It was neutralized with dilute HCl, filtered, washed with water and dried to get the crude 1-hydroxy-3-methyl-9H-carbazole-2- carbaldehyde (I). It was purified by column chromatography over silica using petroleum ether:ethyl acetate (98:2) as eluant. The yellow pure product obtained was recrystallized using glacial acetic acid (52%, 0.940 g).

S3. Refinement

H1, H9, and H21 atoms were located in a difference map and refined isotropically [O1–H1 = 1.00 (4), N9–H9 = 0.91 (2) and C21–H21 = 1.02 (2) Å]. Other H atoms were positioned geometrically and allowed to ride on their parent atoms, with C–H = 0.95–0.98 Å and with U_iso(H) = 1.2–1.5 times U_eq(C).

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2003).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-numbering scheme and with displacement ellipsoids drawn at the 50% probability level. H atoms involved in hydrogen bonding have been labelled.
	Fig. 2. The packing of (I), viewed down the b axis. Dashed lines indicate hydrogen bonds.
	Fig. 3. The packing of (I), viewed down the c axis. Dashed lines indicate hydrogen bonds. The O1–H1···O21 intramolecular hydrogen bond forms a 6-membered ring and the N9–H9···O1(-x,1 - y,-z) intermolecular hydrogen bond forms a 10-membered ring; these favour the planarity of the title molecule (I).

1-Hydroxy-3-methyl-9H-carbazole-2-carbaldehyde

Crystal data

C14H11NO2	F(000) = 472
Mr = 225.24	Dx = 1.414 Mg m^−3
Monoclinic, P21/n	Melting point: 442(1) K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 12.1859 (6) Å	Cell parameters from 2612 reflections
b = 6.6703 (3) Å	θ = 2.0–27.5°
c = 14.1899 (7) Å	µ = 0.10 mm^−1
β = 113.469 (2)°	T = 160 K
V = 1057.99 (9) Å^3	Needle, dark_brown
Z = 4	0.25 × 0.25 × 0.10 mm

Data collection

Nonius KappaCCD area-detector diffractometer	1803 reflections with I > 2σ(I)
Radiation source: Nonius FR590 sealed tube generator	Rint = 0.083
Horizontally mounted graphite crystal monochromator	θmax = 27.5°, θmin = 2.8°
Detector resolution: 9 pixels mm^-1	h = −15→15
φ and ω scans with κ offsets	k = −8→8
25678 measured reflections	l = −18→16
2424 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.053	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.148	w = 1/[σ^2(Fo^2) + (0.0768P)^2 + 0.3576P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
2424 reflections	Δρmax = 0.29 e Å^−3
168 parameters	Δρmin = −0.30 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.030 (6)

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	−0.05055 (11)	0.43004 (18)	0.11451 (10)	0.0297 (4)
O21	−0.17265 (12)	0.3665 (2)	0.22106 (10)	0.0357 (5)
N9	0.12632 (13)	0.2634 (2)	0.04520 (11)	0.0253 (5)
C1	−0.00308 (15)	0.2454 (3)	0.14466 (13)	0.0229 (5)
C2	−0.03616 (14)	0.1239 (3)	0.20958 (12)	0.0227 (5)
C3	0.01660 (15)	−0.0705 (3)	0.24040 (12)	0.0240 (5)
C4	0.10098 (15)	−0.1368 (3)	0.20630 (13)	0.0244 (5)
C4A	0.13332 (14)	−0.0161 (2)	0.13988 (12)	0.0212 (5)
C4B	0.21270 (14)	−0.0436 (3)	0.08768 (12)	0.0238 (5)
C5	0.28668 (15)	−0.1995 (3)	0.08392 (13)	0.0296 (6)
C6	0.34962 (16)	−0.1795 (3)	0.02211 (14)	0.0333 (6)
C7	0.33931 (15)	−0.0049 (3)	−0.03579 (14)	0.0319 (6)
C8	0.26765 (15)	0.1521 (3)	−0.03319 (13)	0.0284 (6)
C8A	0.20392 (14)	0.1315 (3)	0.02920 (12)	0.0239 (5)
C9A	0.08162 (14)	0.1734 (3)	0.11020 (12)	0.0224 (5)
C21	−0.12595 (16)	0.1981 (3)	0.24268 (14)	0.0297 (6)
C31	−0.01876 (17)	−0.2000 (3)	0.31074 (14)	0.0315 (6)
H1	−0.106 (3)	0.460 (4)	0.149 (2)	0.081 (9)*
H4	0.13758	−0.26405	0.22743	0.0292*
H5	0.29383	−0.31779	0.12321	0.0355*
H6	0.40031	−0.28510	0.01884	0.0400*
H7	0.38310	0.00514	−0.07800	0.0382*
H8	0.26164	0.27031	−0.07232	0.0340*
H9	0.0972 (18)	0.377 (3)	0.0086 (16)	0.037 (6)*
H21	−0.1541 (18)	0.109 (3)	0.2875 (15)	0.036 (5)*
H31A	0.02338	−0.32857	0.32138	0.0473*
H31B	−0.10528	−0.22344	0.27962	0.0473*
H31C	0.00264	−0.13214	0.37695	0.0473*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0363 (7)	0.0229 (7)	0.0353 (7)	0.0073 (5)	0.0199 (6)	0.0055 (5)
O21	0.0362 (8)	0.0332 (8)	0.0439 (8)	0.0032 (6)	0.0224 (6)	−0.0032 (6)
N9	0.0270 (8)	0.0259 (8)	0.0256 (8)	0.0022 (6)	0.0132 (6)	0.0057 (6)
C1	0.0225 (8)	0.0207 (8)	0.0232 (8)	−0.0003 (7)	0.0066 (7)	−0.0021 (7)
C2	0.0205 (8)	0.0250 (9)	0.0218 (8)	−0.0030 (7)	0.0077 (7)	−0.0028 (7)
C3	0.0217 (8)	0.0266 (9)	0.0218 (8)	−0.0049 (7)	0.0066 (7)	0.0002 (7)
C4	0.0239 (9)	0.0231 (9)	0.0241 (9)	−0.0006 (7)	0.0074 (7)	0.0014 (7)
C4A	0.0179 (8)	0.0237 (8)	0.0205 (8)	−0.0017 (7)	0.0061 (6)	−0.0008 (7)
C4B	0.0189 (8)	0.0291 (9)	0.0216 (8)	−0.0003 (7)	0.0062 (7)	−0.0008 (7)
C5	0.0251 (9)	0.0321 (10)	0.0295 (10)	0.0036 (8)	0.0086 (7)	−0.0006 (8)
C6	0.0245 (9)	0.0421 (11)	0.0332 (10)	0.0066 (8)	0.0113 (8)	−0.0037 (9)
C7	0.0237 (9)	0.0472 (12)	0.0255 (9)	−0.0003 (8)	0.0107 (7)	−0.0038 (8)
C8	0.0238 (9)	0.0374 (11)	0.0238 (9)	−0.0014 (7)	0.0093 (7)	0.0013 (7)
C8A	0.0194 (8)	0.0302 (10)	0.0207 (8)	−0.0010 (7)	0.0065 (7)	0.0000 (7)
C9A	0.0207 (8)	0.0238 (9)	0.0221 (8)	−0.0017 (7)	0.0080 (7)	0.0011 (7)
C21	0.0287 (10)	0.0326 (10)	0.0299 (10)	−0.0035 (8)	0.0138 (8)	−0.0038 (8)
C31	0.0324 (10)	0.0331 (10)	0.0319 (10)	−0.0027 (8)	0.0159 (8)	0.0072 (8)

Geometric parameters (Å, º)

O1—C1	1.356 (2)	C4B—C8A	1.412 (3)
O21—C21	1.241 (2)	C4B—C5	1.391 (3)
O1—H1	1.00 (4)	C5—C6	1.382 (3)
N9—C8A	1.375 (2)	C6—C7	1.402 (3)
N9—C9A	1.381 (2)	C7—C8	1.373 (3)
N9—H9	0.91 (2)	C8—C8A	1.398 (3)
C1—C9A	1.392 (3)	C4—H4	0.9500
C1—C2	1.401 (3)	C5—H5	0.9500
C2—C21	1.440 (3)	C6—H6	0.9500
C2—C3	1.436 (3)	C7—H7	0.9500
C3—C4	1.372 (3)	C8—H8	0.9500
C3—C31	1.507 (3)	C21—H21	1.02 (2)
C4—C4A	1.410 (2)	C31—H31A	0.9800
C4A—C4B	1.445 (3)	C31—H31B	0.9800
C4A—C9A	1.400 (2)	C31—H31C	0.9800
O1···O21	2.544 (2)	C21···H31C	2.9300
O1···N9	2.922 (2)	C21···H31B	2.8500
O1···C4^i	3.397 (2)	C21···H1	2.27 (3)
O1···N9^ii	2.9160 (19)	C31···H1^vii	3.10 (3)
O21···O1	2.544 (2)	C31···H21	2.58 (2)
O21···C31^i	3.405 (2)	C31···H7^ix	3.0900
O1···H9^ii	2.06 (2)	H1···O21	1.66 (3)
O1···H9	2.79 (2)	H1···C21	2.27 (3)
O21···H1	1.66 (3)	H1···C31^i	3.10 (3)
O21···H31B^i	2.8800	H1···H8^ii	2.5200
O21···H21^iii	2.62 (2)	H1···H9^ii	2.53 (4)
O21···H31B^iii	2.7700	H4···H31A	2.3200
O21···H7^iv	2.7900	H5···C2^viii	2.9900
N9···O1	2.922 (2)	H5···C3^viii	2.8900
N9···O1^ii	2.9160 (19)	H5···C4^viii	3.0900
C1···C4B^v	3.535 (2)	H7···O21^x	2.7900
C2···C5^vi	3.482 (2)	H7···C31^xi	3.0900
C2···C8^v	3.462 (3)	H8···H1^ii	2.5200
C3···C8^v	3.582 (3)	H9···O1	2.79 (2)
C4···O1^vii	3.397 (2)	H9···O1^ii	2.06 (2)
C4B···C1^v	3.535 (2)	H9···H1^ii	2.53 (4)
C5···C2^viii	3.482 (2)	H21···C31	2.58 (2)
C7···C21^v	3.311 (3)	H21···H31B	2.3100
C8···C2^v	3.462 (3)	H21···H31C	2.4300
C8···C31^vi	3.551 (3)	H21···O21^xii	2.62 (2)
C8···C3^v	3.582 (3)	H31A···H4	2.3200
C21···C7^v	3.311 (3)	H31A···C7^viii	3.0600
C31···O21^vii	3.405 (2)	H31A···C8^viii	3.0700
C31···C8^viii	3.551 (3)	H31B···O21^vii	2.8800
C2···H5^vi	2.9900	H31B···C21	2.8500
C3···H5^vi	2.8900	H31B···H21	2.3100
C4···H5^vi	3.0900	H31B···O21^xii	2.7700
C7···H31A^vi	3.0600	H31C···C21	2.9300
C8···H31A^vi	3.0700	H31C···H21	2.4300
C1—O1—H1	108.3 (15)	N9—C8A—C4B	109.17 (15)
C8A—N9—C9A	108.19 (14)	N9—C8A—C8	129.33 (17)
C9A—N9—H9	125.2 (15)	N9—C9A—C1	129.01 (18)
C8A—N9—H9	125.3 (15)	N9—C9A—C4A	110.08 (16)
O1—C1—C9A	119.05 (17)	C1—C9A—C4A	120.91 (17)
O1—C1—C2	122.32 (17)	O21—C21—C2	124.32 (18)
C2—C1—C9A	118.63 (18)	C3—C4—H4	120.00
C1—C2—C3	120.75 (17)	C4A—C4—H4	120.00
C1—C2—C21	118.08 (18)	C4B—C5—H5	121.00
C3—C2—C21	121.16 (17)	C6—C5—H5	121.00
C4—C3—C31	120.06 (18)	C5—C6—H6	120.00
C2—C3—C4	119.41 (17)	C7—C6—H6	120.00
C2—C3—C31	120.53 (17)	C6—C7—H7	119.00
C3—C4—C4A	119.99 (17)	C8—C7—H7	119.00
C4—C4A—C4B	133.83 (15)	C7—C8—H8	121.00
C4—C4A—C9A	120.30 (16)	C8A—C8—H8	121.00
C4B—C4A—C9A	105.86 (14)	O21—C21—H21	116.4 (12)
C5—C4B—C8A	119.63 (16)	C2—C21—H21	119.3 (12)
C4A—C4B—C8A	106.66 (16)	C3—C31—H31A	109.00
C4A—C4B—C5	133.69 (17)	C3—C31—H31B	109.00
C4B—C5—C6	118.94 (18)	C3—C31—H31C	109.00
C5—C6—C7	120.61 (19)	H31A—C31—H31B	109.00
C6—C7—C8	121.82 (18)	H31A—C31—H31C	109.00
C7—C8—C8A	117.50 (18)	H31B—C31—H31C	109.00
C4B—C8A—C8	121.50 (18)
C9A—N9—C8A—C8	177.63 (18)	C3—C4—C4A—C9A	1.4 (3)
C8A—N9—C9A—C1	−177.12 (18)	C4—C4A—C4B—C8A	178.29 (18)
C8A—N9—C9A—C4A	2.04 (19)	C9A—C4A—C4B—C5	−178.54 (19)
C9A—N9—C8A—C4B	−2.10 (19)	C9A—C4A—C4B—C8A	−0.13 (18)
O1—C1—C9A—N9	−1.2 (3)	C4—C4A—C4B—C5	−0.1 (3)
O1—C1—C9A—C4A	179.69 (16)	C4B—C4A—C9A—C1	178.08 (16)
C9A—C1—C2—C21	−178.53 (16)	C4—C4A—C9A—N9	−179.83 (15)
O1—C1—C2—C3	−179.63 (16)	C4—C4A—C9A—C1	−0.6 (3)
O1—C1—C2—C21	1.5 (3)	C4B—C4A—C9A—N9	−1.16 (19)
C9A—C1—C2—C3	0.3 (3)	C8A—C4B—C5—C6	−0.4 (3)
C2—C1—C9A—C4A	−0.2 (3)	C4A—C4B—C8A—N9	1.37 (19)
C2—C1—C9A—N9	178.83 (17)	C4A—C4B—C8A—C8	−178.39 (16)
C21—C2—C3—C31	−1.6 (3)	C4A—C4B—C5—C6	177.86 (18)
C21—C2—C3—C4	179.28 (17)	C5—C4B—C8A—N9	−179.95 (17)
C1—C2—C3—C4	0.5 (3)	C5—C4B—C8A—C8	0.3 (3)
C1—C2—C21—O21	−3.2 (3)	C4B—C5—C6—C7	0.1 (3)
C3—C2—C21—O21	177.99 (17)	C5—C6—C7—C8	0.3 (3)
C1—C2—C3—C31	179.63 (16)	C6—C7—C8—C8A	−0.4 (3)
C2—C3—C4—C4A	−1.3 (3)	C7—C8—C8A—N9	−179.57 (18)
C31—C3—C4—C4A	179.53 (16)	C7—C8—C8A—C4B	0.1 (3)
C3—C4—C4A—C4B	−176.84 (18)

Symmetry codes: (i) x, y+1, z; (ii) −x, −y+1, −z; (iii) −x−1/2, y+1/2, −z+1/2; (iv) x−1/2, −y+1/2, z+1/2; (v) −x, −y, −z; (vi) −x+1/2, y+1/2, −z+1/2; (vii) x, y−1, z; (viii) −x+1/2, y−1/2, −z+1/2; (ix) x−1/2, −y−1/2, z+1/2; (x) x+1/2, −y+1/2, z−1/2; (xi) x+1/2, −y−1/2, z−1/2; (xii) −x−1/2, y−1/2, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O21	1.00 (4)	1.66 (3)	2.544 (2)	145 (2)
N9—H9···O1^ii	0.91 (2)	2.06 (2)	2.9160 (19)	157.0 (19)

Symmetry code: (ii) −x, −y+1, −z.