Ethyl (2,3-dihydro-1H,1′H-2,3′-biindol-1-yl)glyoxylate

The crystal structure of the title compound, C₂₀H₁₈N₂O₃, was determined in the course of our studies of the synthesis of 3-acyl­indole derivatives. We obtained it as an unexpected racemic side product. The crystal structure contains chains of dimers along the a axis.

Key indicators

• Single-crystal X-ray study
• T = 193 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.050
• wR factor = 0.147
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of Tmax/Tmin expected RT(exp) is > 1.10
            Absorption corrections should be applied.
            Tmin and Tmax expected:      0.678     0.773
            RT(exp) =      1.140
PLAT057_ALERT_3_C Correction for Absorption Required   RT(exp) ...       1.14
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.32 Ratio
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C19    -   C21    ...       1.53 Ang.
PLAT751_ALERT_4_C Bond    Calc     0.88000, Rep     0.88(2) ......  Senseless su
              N12  -H12     1.555   1.555
PLAT752_ALERT_4_C Angle   Calc      125.00, Rep    124.9(9) ......  Senseless su
              C11  -N12  -H12     1.555   1.555   1.555
PLAT752_ALERT_4_C Angle   Calc      125.00, Rep   124.7(10) ......  Senseless su
              C13  -N12  -H12     1.555   1.555   1.555
PLAT755_ALERT_4_C D-H     Calc     0.88000, Rep     0.88(2) ......  Senseless su
              N12  -H12     1.555   1.555
PLAT755_ALERT_4_C D-H     Calc     0.88000, Rep     0.88(2) ......  Senseless su
              N12  -H12     1.555   1.555
PLAT756_ALERT_4_C H...A   Calc     2.29000, Rep   2.286(12) ......  Senseless su
              H12  -O20     1.555   2.657
PLAT756_ALERT_4_C H...A   Calc     2.41000, Rep     2.41(3) ......  Senseless su
              H12  -O20     1.555   1.455

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
  12 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
   7 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: CORINC (Dräger & Gattow, 1971); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Ethyl (2,3-dihydro-1H,1'H-2,3'-biindol-1-yl)glyoxylate

Crystal data

C20H18N2O3	Z = 2
Mr = 334.37	F(000) = 352
Triclinic, P1	Dx = 1.329 Mg m^−3
Hall symbol: -P 1	Melting point: 168.2 K
a = 8.441 (3) Å	Cu Kα radiation, λ = 1.54178 Å
b = 9.596 (3) Å	Cell parameters from 25 reflections
c = 10.925 (4) Å	θ = 65–70°
α = 96.11 (2)°	µ = 0.73 mm^−1
β = 96.49 (3)°	T = 193 K
γ = 106.13 (2)°	Block, colourless
V = 835.8 (4) Å^3	0.60 × 0.50 × 0.35 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	Rint = 0.026
Radiation source: rotating anode	θmax = 69.8°, θmin = 4.1°
Graphite monochromator	h = −10→0
ω/2θ scans	k = −11→11
3396 measured reflections	l = −13→13
3163 independent reflections	3 standard reflections every 60 min
3075 reflections with I > 2σ(I)	intensity decay: 5%

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)] = 0.050	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.147	w = 1/[σ^2(Fo^2) + (0.093P)^2 + 0.3021P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
3163 reflections	Δρmax = 0.28 e Å^−3
242 parameters	Δρmin = −0.32 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.036 (3)

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.

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
C1	0.7233 (2)	0.46349 (18)	1.05023 (16)	0.0356 (4)
H1A	0.7529	0.5656	1.0318	0.039 (4)*
H1B	0.6241	0.4457	1.0934	0.039 (4)*
C2	0.68925 (18)	0.35349 (16)	0.92911 (14)	0.0276 (3)
H2	0.7298	0.4083	0.8604	0.025 (4)*
N3	0.79869 (15)	0.25693 (13)	0.95875 (11)	0.0267 (3)
C4	0.90499 (18)	0.31466 (16)	1.07411 (13)	0.0267 (3)
C5	1.02942 (19)	0.26304 (17)	1.13120 (15)	0.0319 (4)
H5	1.0560	0.1806	1.0926	0.036 (5)*
C6	1.1131 (2)	0.33723 (19)	1.24710 (16)	0.0385 (4)
H6	1.1974	0.3038	1.2890	0.050 (6)*
C7	1.0763 (2)	0.4588 (2)	1.30280 (16)	0.0407 (4)
H7	1.1353	0.5076	1.3820	0.058 (6)*
C8	0.9532 (2)	0.50981 (18)	1.24335 (16)	0.0371 (4)
H8	0.9286	0.5937	1.2810	0.039 (5)*
C9	0.86708 (19)	0.43651 (16)	1.12847 (14)	0.0297 (4)
C10	0.51018 (19)	0.26691 (16)	0.88940 (14)	0.0276 (3)
C11	0.4103 (2)	0.17663 (18)	0.95615 (15)	0.0340 (4)
H11	0.4432	0.1596	1.0379	0.036 (5)*
N12	0.25563 (18)	0.11426 (16)	0.88776 (14)	0.0385 (4)
H12	0.168 (3)	0.0630 (16)	0.9166 (9)	0.060 (7)*
C13	0.2511 (2)	0.16454 (18)	0.77499 (16)	0.0344 (4)
C14	0.1237 (2)	0.1301 (2)	0.67309 (18)	0.0438 (5)
H14	0.0182	0.0621	0.6747	0.041 (5)*
C15	0.1569 (2)	0.1985 (2)	0.57054 (17)	0.0486 (5)
H15	0.0728	0.1772	0.5000	0.056 (6)*
C16	0.3118 (2)	0.2985 (2)	0.56809 (17)	0.0462 (5)
H16	0.3302	0.3451	0.4963	0.061 (7)*
C17	0.4388 (2)	0.33135 (19)	0.66736 (15)	0.0368 (4)
H17	0.5438	0.3992	0.6642	0.045 (5)*
C18	0.40991 (19)	0.26274 (17)	0.77294 (14)	0.0294 (4)
C19	0.79481 (18)	0.13371 (16)	0.88648 (13)	0.0263 (3)
O20	0.87899 (14)	0.05151 (12)	0.91221 (10)	0.0331 (3)
C21	0.68430 (18)	0.09435 (16)	0.75941 (14)	0.0274 (3)
O22	0.71349 (14)	0.16421 (12)	0.67524 (10)	0.0343 (3)
O23	0.56690 (14)	−0.03203 (12)	0.75343 (10)	0.0345 (3)
C24	0.4610 (2)	−0.08704 (19)	0.63301 (15)	0.0375 (4)
H24A	0.5286	−0.1064	0.5685	0.045 (4)*
H24B	0.4055	−0.0140	0.6079	0.045 (4)*
C25	0.3338 (3)	−0.2257 (3)	0.6473 (2)	0.0636 (7)
H25A	0.2603	−0.2659	0.5679	0.083 (5)*
H25B	0.2675	−0.2051	0.7112	0.083 (5)*
H25C	0.3902	−0.2970	0.6722	0.083 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0374 (9)	0.0317 (8)	0.0381 (9)	0.0146 (7)	0.0018 (7)	−0.0017 (6)
C2	0.0294 (8)	0.0274 (7)	0.0291 (7)	0.0129 (6)	0.0036 (6)	0.0059 (6)
N3	0.0265 (6)	0.0294 (6)	0.0255 (6)	0.0120 (5)	0.0002 (5)	0.0033 (5)
C4	0.0264 (7)	0.0272 (7)	0.0250 (7)	0.0055 (6)	0.0022 (6)	0.0050 (6)
C5	0.0309 (8)	0.0319 (8)	0.0320 (8)	0.0098 (6)	−0.0012 (6)	0.0049 (6)
C6	0.0357 (9)	0.0412 (9)	0.0344 (9)	0.0081 (7)	−0.0057 (7)	0.0079 (7)
C7	0.0399 (9)	0.0436 (9)	0.0291 (8)	0.0025 (7)	−0.0033 (7)	−0.0014 (7)
C8	0.0406 (9)	0.0325 (8)	0.0336 (8)	0.0063 (7)	0.0048 (7)	−0.0031 (6)
C9	0.0301 (8)	0.0275 (7)	0.0306 (8)	0.0068 (6)	0.0049 (6)	0.0036 (6)
C10	0.0287 (7)	0.0298 (7)	0.0277 (7)	0.0138 (6)	0.0046 (6)	0.0045 (6)
C11	0.0328 (8)	0.0386 (9)	0.0338 (8)	0.0139 (7)	0.0070 (6)	0.0077 (6)
N12	0.0308 (7)	0.0407 (8)	0.0429 (8)	0.0071 (6)	0.0104 (6)	0.0054 (6)
C13	0.0294 (8)	0.0375 (8)	0.0368 (9)	0.0139 (7)	0.0046 (6)	−0.0028 (7)
C14	0.0302 (8)	0.0497 (10)	0.0469 (10)	0.0151 (7)	−0.0023 (7)	−0.0133 (8)
C15	0.0433 (10)	0.0643 (12)	0.0363 (9)	0.0260 (9)	−0.0104 (7)	−0.0116 (8)
C16	0.0519 (11)	0.0613 (12)	0.0303 (9)	0.0282 (9)	−0.0016 (8)	0.0044 (8)
C17	0.0386 (9)	0.0433 (9)	0.0310 (8)	0.0165 (7)	0.0033 (7)	0.0059 (7)
C18	0.0284 (7)	0.0329 (8)	0.0293 (8)	0.0149 (6)	0.0030 (6)	0.0008 (6)
C19	0.0251 (7)	0.0279 (7)	0.0269 (7)	0.0089 (6)	0.0034 (6)	0.0048 (6)
O20	0.0348 (6)	0.0325 (6)	0.0345 (6)	0.0172 (5)	−0.0008 (4)	0.0014 (4)
C21	0.0283 (7)	0.0287 (7)	0.0268 (7)	0.0115 (6)	0.0040 (6)	0.0026 (6)
O22	0.0368 (6)	0.0379 (6)	0.0283 (6)	0.0098 (5)	0.0053 (4)	0.0081 (5)
O23	0.0388 (6)	0.0333 (6)	0.0256 (6)	0.0034 (5)	0.0001 (5)	0.0032 (4)
C24	0.0403 (9)	0.0404 (9)	0.0243 (8)	0.0035 (7)	0.0002 (6)	−0.0010 (6)
C25	0.0646 (14)	0.0592 (13)	0.0416 (11)	−0.0171 (11)	−0.0019 (9)	0.0011 (9)

Geometric parameters (Å, º)

C1—C9	1.502 (2)	C19—C21	1.530 (2)
C1—C2	1.548 (2)	C21—O22	1.2026 (19)
C2—C10	1.497 (2)	C21—O23	1.3259 (19)
C2—N3	1.5129 (18)	O23—C24	1.4606 (19)
N3—C19	1.340 (2)	C24—C25	1.495 (3)
N3—C4	1.4213 (19)	C1—H1A	0.990
C4—C9	1.388 (2)	C1—H1B	0.990
C4—C5	1.394 (2)	C2—H2	1.000
C5—C6	1.391 (2)	C5—H5	0.950
C6—C7	1.386 (3)	C6—H6	0.950
C7—C8	1.392 (3)	C7—H7	0.950
C8—C9	1.386 (2)	C8—H8	0.950
C10—C11	1.364 (2)	C11—H11	0.950
C10—C18	1.437 (2)	N12—H12	0.88 (2)
C11—N12	1.368 (2)	C14—H14	0.950
N12—C13	1.370 (2)	C15—H15	0.950
C13—C14	1.400 (2)	C16—H16	0.950
C13—C18	1.413 (2)	C17—H17	0.950
C14—C15	1.375 (3)	C24—H24A	0.990
C15—C16	1.396 (3)	C24—H24B	0.990
C16—C17	1.379 (2)	C25—H25A	0.980
C17—C18	1.400 (2)	C25—H25B	0.980
C19—O20	1.2329 (18)	C25—H25C	0.980
C9—C1—C2	105.03 (12)	C11—N12—H12	124.9 (9)
C10—C2—N3	112.22 (12)	C13—N12—H12	124.7 (10)
C10—C2—C1	114.77 (13)	C2—C1—H1A	111.0
N3—C2—C1	103.21 (12)	C2—C1—H1B	111.0
C19—N3—C4	124.90 (12)	C9—C1—H1A	111.0
C19—N3—C2	124.59 (12)	C9—C1—H1B	111.0
C4—N3—C2	110.51 (12)	H1A—C1—H1B	109.0
C9—C4—C5	121.97 (14)	N3—C2—H2	109.0
C9—C4—N3	109.57 (13)	C1—C2—H2	109.0
C5—C4—N3	128.47 (14)	C10—C2—H2	109.0
C6—C5—C4	117.24 (15)	C4—C5—H5	121.0
C7—C6—C5	121.46 (16)	C6—C5—H5	121.0
C6—C7—C8	120.36 (15)	C5—C6—H6	119.0
C9—C8—C7	119.09 (16)	C7—C6—H6	119.0
C8—C9—C4	119.87 (15)	C6—C7—H7	120.0
C8—C9—C1	129.22 (15)	C8—C7—H7	120.0
C4—C9—C1	110.82 (13)	C7—C8—H8	120.0
C11—C10—C18	106.55 (14)	C9—C8—H8	120.0
C11—C10—C2	126.94 (14)	N12—C11—H11	125.0
C18—C10—C2	126.51 (14)	C10—C11—H11	125.0
C10—C11—N12	109.86 (15)	C13—C14—H14	121.0
C11—N12—C13	109.49 (14)	C15—C14—H14	121.0
N12—C13—C14	130.80 (17)	C14—C15—H15	119.0
N12—C13—C18	107.19 (14)	C16—C15—H15	119.0
C14—C13—C18	121.98 (17)	C15—C16—H16	119.0
C15—C14—C13	117.49 (17)	C17—C16—H16	119.0
C14—C15—C16	121.28 (16)	C16—C17—H17	121.0
C17—C16—C15	121.58 (18)	C18—C17—H17	121.0
C16—C17—C18	118.72 (17)	O23—C24—H24A	110.0
C17—C18—C13	118.92 (15)	O23—C24—H24B	110.0
C17—C18—C10	134.19 (15)	C25—C24—H24A	110.0
C13—C18—C10	106.89 (14)	C25—C24—H24B	110.0
O20—C19—N3	124.97 (14)	H24A—C24—H24B	109.0
O20—C19—C21	116.76 (13)	C24—C25—H25A	109.0
N3—C19—C21	118.20 (12)	C24—C25—H25B	109.0
O22—C21—O23	126.33 (14)	C24—C25—H25C	109.0
O22—C21—C19	122.81 (14)	H25A—C25—H25B	109.0
O23—C21—C19	110.52 (12)	H25A—C25—H25C	109.0
C21—O23—C24	115.65 (12)	H25B—C25—H25C	109.0
O23—C24—C25	107.25 (14)
C9—C1—C2—C10	131.43 (14)	C10—C11—N12—C13	−0.79 (19)
C9—C1—C2—N3	9.01 (15)	C11—N12—C13—C14	178.03 (17)
C10—C2—N3—C19	47.13 (19)	C11—N12—C13—C18	−0.05 (18)
C1—C2—N3—C19	171.23 (14)	N12—C13—C14—C15	−179.41 (16)
C10—C2—N3—C4	−132.47 (13)	C18—C13—C14—C15	−1.6 (2)
C1—C2—N3—C4	−8.36 (15)	C13—C14—C15—C16	0.0 (3)
C19—N3—C4—C9	−175.34 (13)	C14—C15—C16—C17	1.0 (3)
C2—N3—C4—C9	4.26 (16)	C15—C16—C17—C18	−0.4 (3)
C19—N3—C4—C5	4.0 (2)	C16—C17—C18—C13	−1.2 (2)
C2—N3—C4—C5	−176.44 (14)	C16—C17—C18—C10	178.40 (16)
C9—C4—C5—C6	1.2 (2)	N12—C13—C18—C17	−179.52 (14)
N3—C4—C5—C6	−178.01 (15)	C14—C13—C18—C17	2.2 (2)
C4—C5—C6—C7	−1.0 (2)	N12—C13—C18—C10	0.81 (17)
C5—C6—C7—C8	0.1 (3)	C14—C13—C18—C10	−177.47 (14)
C6—C7—C8—C9	0.6 (3)	C11—C10—C18—C17	179.13 (17)
C7—C8—C9—C4	−0.4 (2)	C2—C10—C18—C17	−0.9 (3)
C7—C8—C9—C1	175.70 (16)	C11—C10—C18—C13	−1.27 (17)
C5—C4—C9—C8	−0.5 (2)	C2—C10—C18—C13	178.66 (13)
N3—C4—C9—C8	178.82 (13)	C4—N3—C19—O20	2.4 (2)
C5—C4—C9—C1	−177.32 (14)	C2—N3—C19—O20	−177.09 (13)
N3—C4—C9—C1	2.04 (18)	C4—N3—C19—C21	−174.51 (12)
C2—C1—C9—C8	176.41 (16)	C2—N3—C19—C21	6.0 (2)
C2—C1—C9—C4	−7.20 (18)	O20—C19—C21—O22	−108.88 (17)
N3—C2—C10—C11	58.8 (2)	N3—C19—C21—O22	68.3 (2)
C1—C2—C10—C11	−58.6 (2)	O20—C19—C21—O23	64.81 (17)
N3—C2—C10—C18	−121.11 (15)	N3—C19—C21—O23	−117.99 (15)
C1—C2—C10—C18	121.48 (16)	O22—C21—O23—C24	−2.1 (2)
C18—C10—C11—N12	1.27 (18)	C19—C21—O23—C24	−175.53 (12)
C2—C10—C11—N12	−178.66 (14)	C21—O23—C24—C25	−177.69 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N12—H12···O20^i	0.88 (2)	2.29 (1)	2.982 (2)	136 (2)
N12—H12···O20^ii	0.88 (2)	2.41 (3)	3.115 (2)	138 (2)

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