Ethyl (3-ethyl-1-oxo-1,2,3,4-tetra­hydro­carbazol-2-yl)­acetate

The title compound, C₁₈H₂₁NO₃, consists of a carbazole skeleton with carboxy­ethyl and ethyl groups at positions 2 and 3, respectively. The heterocyclic ring and the benzene ring fused to it are nearly planar, while the cyclohexenone ring adopts a distorted sofa conformation. Molecules are linked in pairs about inversion centers by N—H...O hydrogen bonds [N...O = 2.831 (3) Å and N—H...O = 158 (3)°].

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.047
• wR factor = 0.145
• Data-to-parameter ratio = 12.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT027_ALERT_3_A _diffrn_reflns_theta_full (too) Low ............      24.28 Deg.

Alert level C
THETM01_ALERT_3_C  The value of sine(theta_max)/wavelength is less than 0.590
            Calculated sin(theta_max)/wavelength =    0.5786
PLAT023_ALERT_3_C Resolution (too) Low [sin(th)/Lambda < 0.6].....      24.28 Deg.
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        C13

   1 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP (Johnson, 1965); software used to prepare material for publication: PARST (Nardelli, 1995).

(I)

Crystal data

C18H21NO3	F(000) = 1280
Mr = 299.36	Dx = 1.226 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 15.0923 (11) Å	Cell parameters from 22 reflections
b = 8.0510 (5) Å	θ = 9.3–18.1°
c = 26.928 (2) Å	µ = 0.08 mm^−1
β = 97.535 (8)°	T = 295 K
V = 3243.7 (4) Å^3	Prism, colorless
Z = 8	0.48 × 0.42 × 0.12 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.052
ω/2θ scans	θmax = 24.3°, θmin = 2.7°
Absorption correction: ψ scan (North et al., 1968)	h = −17→17
Tmin = 0.961, Tmax = 0.990	k = 0→9
5078 measured reflections	l = −31→31
2632 independent reflections	3 standard reflections every 120 min
1344 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	1 restraint
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.047	w = 1/[σ^2(Fo^2) + (0.0725P)^2 + 0.4277P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.145	(Δ/σ)max = 0.001
S = 0.99	Δρmax = 0.21 e Å^−3
2619 reflections	Δρmin = −0.18 e Å^−3
203 parameters

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
H9	1.079 (2)	0.070 (3)	0.5277 (11)	0.096 (11)*
O3	0.85728 (13)	0.1134 (2)	0.30699 (7)	0.0643 (6)
N9	1.09993 (15)	0.1774 (3)	0.52207 (8)	0.0507 (6)
O1	0.96495 (14)	0.1138 (3)	0.43607 (7)	0.0774 (7)
C9A	1.07889 (17)	0.2757 (3)	0.48015 (9)	0.0465 (7)
C2	1.01312 (18)	0.3555 (3)	0.39366 (10)	0.0551 (8)
H2	1.0641	0.326	0.3764	0.066*
C5A	1.18449 (17)	0.4081 (3)	0.53089 (10)	0.0501 (7)
C8A	1.16481 (16)	0.2559 (3)	0.55333 (10)	0.0478 (7)
C4A	1.12874 (17)	0.4180 (3)	0.48459 (10)	0.0466 (7)
C1	1.01429 (19)	0.2355 (3)	0.43778 (10)	0.0540 (7)
O2	1.00497 (16)	0.1055 (3)	0.31901 (9)	0.0982 (9)
C4	1.11668 (18)	0.5503 (3)	0.44575 (10)	0.0566 (8)
H4A	1.1654	0.5447	0.4256	0.068*
H4B	1.1193	0.658	0.4621	0.068*
C12	0.92915 (19)	0.3245 (4)	0.35656 (10)	0.0621 (8)
H12A	0.878	0.3153	0.3747	0.074*
H12B	0.9192	0.4186	0.334	0.074*
C8	1.20640 (17)	0.2098 (4)	0.60070 (10)	0.0565 (8)
H8	1.1921	0.1106	0.6155	0.068*
C3	1.02812 (19)	0.5346 (3)	0.41158 (11)	0.0584 (8)
H3	0.981	0.5595	0.4323	0.07*
C13	0.9367 (2)	0.1695 (4)	0.32660 (10)	0.0592 (8)
C5	1.24947 (19)	0.5126 (4)	0.55683 (12)	0.0649 (9)
H5	1.2645	0.6128	0.5429	0.078*
C7	1.26856 (18)	0.3151 (5)	0.62455 (11)	0.0671 (9)
H7	1.2973	0.2866	0.6561	0.081*
C10	1.0193 (2)	0.6634 (4)	0.36928 (12)	0.0717 (9)
H10A	0.9577	0.6642	0.3535	0.086*
H10B	1.032	0.7722	0.3839	0.086*
C6	1.2903 (2)	0.4643 (5)	0.60307 (13)	0.0744 (10)
H6	1.3335	0.5326	0.6204	0.089*
C14	0.8574 (2)	−0.0242 (4)	0.27179 (12)	0.0784 (10)
H14A	0.8805	−0.1237	0.2892	0.094*
H14B	0.8951	0.0022	0.2463	0.094*
C15	0.7644 (2)	−0.0514 (5)	0.24845 (13)	0.0897 (11)
H15A	0.7629	−0.1408	0.2247	0.134*
H15B	0.742	0.048	0.2316	0.134*
H15C	0.7279	−0.0792	0.2739	0.134*
C11	1.0787 (2)	0.6368 (5)	0.32932 (13)	0.0963 (12)
H11A	1.068	0.7226	0.3045	0.145*
H11B	1.066	0.5305	0.3138	0.145*
H11C	1.1401	0.6402	0.3441	0.145*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O3	0.0646 (13)	0.0604 (13)	0.0645 (13)	0.0028 (10)	−0.0045 (10)	−0.0134 (11)
N9	0.0625 (15)	0.0404 (14)	0.0477 (14)	−0.0060 (13)	0.0020 (11)	0.0026 (12)
O1	0.0994 (16)	0.0530 (13)	0.0730 (14)	−0.0328 (13)	−0.0147 (12)	0.0107 (11)
C9A	0.0538 (16)	0.0417 (17)	0.0437 (15)	−0.0052 (14)	0.0056 (13)	−0.0009 (14)
C2	0.0639 (18)	0.0488 (19)	0.0509 (17)	0.0003 (14)	0.0015 (14)	0.0008 (14)
C5A	0.0460 (16)	0.0502 (19)	0.0551 (17)	−0.0084 (14)	0.0099 (14)	−0.0064 (15)
C8A	0.0459 (15)	0.0489 (18)	0.0490 (17)	−0.0032 (14)	0.0082 (14)	−0.0063 (15)
C4A	0.0513 (16)	0.0376 (16)	0.0527 (17)	−0.0053 (13)	0.0139 (13)	−0.0005 (13)
C1	0.0655 (18)	0.0394 (17)	0.0562 (18)	−0.0058 (15)	0.0046 (15)	0.0006 (15)
O2	0.0641 (14)	0.124 (2)	0.1018 (18)	0.0163 (15)	−0.0069 (13)	−0.0421 (16)
C4	0.0594 (18)	0.0433 (17)	0.0686 (18)	−0.0089 (14)	0.0142 (15)	−0.0002 (15)
C12	0.0711 (19)	0.0525 (19)	0.0592 (18)	0.0054 (16)	−0.0040 (15)	0.0060 (15)
C8	0.0548 (17)	0.062 (2)	0.0532 (18)	0.0046 (16)	0.0098 (15)	−0.0011 (16)
C3	0.0611 (18)	0.0442 (18)	0.0706 (19)	−0.0034 (14)	0.0118 (15)	0.0084 (15)
C13	0.0597 (19)	0.065 (2)	0.0494 (17)	0.0048 (17)	−0.0052 (15)	0.0006 (16)
C5	0.0584 (18)	0.060 (2)	0.077 (2)	−0.0142 (16)	0.0089 (17)	−0.0048 (17)
C7	0.0546 (18)	0.084 (3)	0.0610 (19)	0.0024 (19)	0.0023 (15)	−0.0109 (19)
C10	0.078 (2)	0.056 (2)	0.083 (2)	−0.0035 (17)	0.0156 (18)	0.0206 (18)
C6	0.057 (2)	0.085 (3)	0.079 (2)	−0.0156 (18)	−0.0026 (18)	−0.019 (2)
C14	0.089 (2)	0.073 (2)	0.070 (2)	0.0025 (19)	−0.0023 (18)	−0.0206 (19)
C15	0.104 (3)	0.077 (3)	0.084 (2)	−0.016 (2)	−0.006 (2)	−0.009 (2)
C11	0.116 (3)	0.091 (3)	0.086 (2)	0.001 (2)	0.026 (2)	0.032 (2)

Geometric parameters (Å, º)

O3—C13	1.324 (3)	C12—H12B	0.97
O3—C14	1.458 (3)	C8—C7	1.362 (4)
N9—C8A	1.360 (3)	C8—H8	0.93
N9—C9A	1.381 (3)	C3—C10	1.533 (4)
N9—H9	0.939 (18)	C3—H3	0.98
O1—C1	1.228 (3)	C5—C6	1.371 (4)
C9A—C4A	1.367 (3)	C5—H5	0.93
C9A—C1	1.437 (4)	C7—C6	1.391 (4)
C2—C12	1.528 (4)	C7—H7	0.93
C2—C3	1.528 (4)	C10—C11	1.504 (4)
C2—C1	1.529 (4)	C10—H10A	0.97
C2—H2	0.98	C10—H10B	0.97
C5A—C5	1.407 (4)	C6—H6	0.93
C5A—C8A	1.414 (4)	C14—C15	1.477 (4)
C5A—C4A	1.412 (4)	C14—H14A	0.97
C8A—C8	1.396 (3)	C14—H14B	0.97
C4A—C4	1.487 (4)	C15—H15A	0.96
O2—C13	1.194 (3)	C15—H15B	0.96
C4—C3	1.525 (4)	C15—H15C	0.96
C4—H4A	0.97	C11—H11A	0.96
C4—H4B	0.97	C11—H11B	0.96
C12—C13	1.498 (4)	C11—H11C	0.96
C12—H12A	0.97
C13—O3—C14	116.1 (2)	C4—C3—C10	112.1 (2)
C8A—N9—C9A	108.0 (2)	C2—C3—C10	114.1 (2)
C8A—N9—H9	123.7 (19)	C4—C3—H3	106.5
C9A—N9—H9	128.0 (19)	C2—C3—H3	106.5
C4A—C9A—N9	110.1 (2)	C10—C3—H3	106.5
C4A—C9A—C1	124.5 (3)	O2—C13—O3	122.7 (3)
N9—C9A—C1	125.4 (2)	O2—C13—C12	125.5 (3)
C12—C2—C3	115.9 (2)	O3—C13—C12	111.7 (3)
C12—C2—C1	109.2 (2)	C6—C5—C5A	118.9 (3)
C3—C2—C1	111.4 (2)	C6—C5—H5	120.6
C12—C2—H2	106.6	C5A—C5—H5	120.6
C3—C2—H2	106.6	C8—C7—C6	121.8 (3)
C1—C2—H2	106.6	C8—C7—H7	119.1
C5—C5A—C8A	118.5 (3)	C6—C7—H7	119.1
C5—C5A—C4A	134.5 (3)	C11—C10—C3	115.7 (3)
C8A—C5A—C4A	107.0 (2)	C11—C10—H10A	108.4
N9—C8A—C8	130.0 (3)	C3—C10—H10A	108.4
N9—C8A—C5A	108.2 (2)	C11—C10—H10B	108.4
C8—C8A—C5A	121.8 (3)	C3—C10—H10B	108.4
C9A—C4A—C5A	106.7 (2)	H10A—C10—H10B	107.4
C9A—C4A—C4	121.6 (2)	C5—C6—C7	121.3 (3)
C5A—C4A—C4	131.7 (2)	C5—C6—H6	119.3
O1—C1—C9A	123.7 (2)	C7—C6—H6	119.3
O1—C1—C2	122.0 (2)	O3—C14—C15	107.9 (3)
C9A—C1—C2	114.3 (2)	O3—C14—H14A	110.1
C4A—C4—C3	112.4 (2)	C15—C14—H14A	110.1
C4A—C4—H4A	109.1	O3—C14—H14B	110.1
C3—C4—H4A	109.1	C15—C14—H14B	110.1
C4A—C4—H4B	109.1	H14A—C14—H14B	108.4
C3—C4—H4B	109.1	C14—C15—H15A	109.5
H4A—C4—H4B	107.9	C14—C15—H15B	109.5
C13—C12—C2	111.9 (2)	H15A—C15—H15B	109.5
C13—C12—H12A	109.2	C14—C15—H15C	109.5
C2—C12—H12A	109.2	H15A—C15—H15C	109.5
C13—C12—H12B	109.2	H15B—C15—H15C	109.5
C2—C12—H12B	109.2	C10—C11—H11A	109.5
H12A—C12—H12B	107.9	C10—C11—H11B	109.5
C7—C8—C8A	117.7 (3)	H11A—C11—H11B	109.5
C7—C8—H8	121.2	C10—C11—H11C	109.5
C8A—C8—H8	121.2	H11A—C11—H11C	109.5
C4—C3—C2	110.5 (2)	H11B—C11—H11C	109.5
C8A—N9—C9A—C4A	−1.0 (3)	C9A—C4A—C4—C3	17.6 (4)
C8A—N9—C9A—C1	178.9 (2)	C5A—C4A—C4—C3	−159.8 (3)
C9A—N9—C8A—C8	178.0 (3)	C3—C2—C12—C13	158.1 (2)
C9A—N9—C8A—C5A	0.6 (3)	C1—C2—C12—C13	−75.2 (3)
C5—C5A—C8A—N9	179.3 (2)	N9—C8A—C8—C7	−178.4 (3)
C4A—C5A—C8A—N9	−0.1 (3)	C5A—C8A—C8—C7	−1.3 (4)
C5—C5A—C8A—C8	1.6 (4)	C4A—C4—C3—C2	−47.2 (3)
C4A—C5A—C8A—C8	−177.7 (2)	C4A—C4—C3—C10	−175.7 (2)
N9—C9A—C4A—C5A	0.9 (3)	C12—C2—C3—C4	−176.5 (2)
C1—C9A—C4A—C5A	−179.0 (2)	C1—C2—C3—C4	57.9 (3)
N9—C9A—C4A—C4	−177.1 (2)	C12—C2—C3—C10	−49.1 (3)
C1—C9A—C4A—C4	3.0 (4)	C1—C2—C3—C10	−174.7 (2)
C5—C5A—C4A—C9A	−179.7 (3)	C14—O3—C13—O2	−5.0 (4)
C8A—C5A—C4A—C9A	−0.5 (3)	C14—O3—C13—C12	172.2 (2)
C5—C5A—C4A—C4	−2.0 (5)	C2—C12—C13—O2	−23.2 (4)
C8A—C5A—C4A—C4	177.2 (3)	C2—C12—C13—O3	159.6 (2)
C4A—C9A—C1—O1	−173.9 (3)	C8A—C5A—C5—C6	−0.9 (4)
N9—C9A—C1—O1	6.2 (4)	C4A—C5A—C5—C6	178.3 (3)
C4A—C9A—C1—C2	7.5 (4)	C8A—C8—C7—C6	0.3 (4)
N9—C9A—C1—C2	−172.3 (2)	C4—C3—C10—C11	70.6 (4)
C12—C2—C1—O1	14.4 (4)	C2—C3—C10—C11	−56.0 (4)
C3—C2—C1—O1	143.6 (3)	C5A—C5—C6—C7	−0.2 (4)
C12—C2—C1—C9A	−167.1 (2)	C8—C7—C6—C5	0.5 (5)
C3—C2—C1—C9A	−37.8 (3)	C13—O3—C14—C15	−171.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N9—H9···O1^i	0.94 (3)	1.94 (3)	2.831 (3)	158 (3)
C14—H14B···O2^ii	0.97	2.60	3.566 (4)	174

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