5-Methoxy-2,3-di­methyl­indole

The attempted sublimation of the anti-inflammatory drug indomethacin gave a decomposition reaction from which crystals of 5-methoxy-2,3-di­methyl­indole, C₁₁H₁₃NO, were isolated. The crystal structure includes a close intermolecular approach of the amine H atom to the face of an indole ring.

Key indicators

• Single-crystal X-ray study
• T = 123 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.044
• wR factor = 0.095
• Data-to-parameter ratio = 9.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_420  Alert C D-H Without Acceptor       N(1)   -   H(1)              ?

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           27.48
         From the CIF: _reflns_number_total               1163
         Count of symmetry unique reflns         1169
         Completeness (_total/calc)             99.49%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured         0
         Fraction of Friedel pairs measured     0.000
         Are heavy atom types Z>Si present           no
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

---

Computing details

Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1988); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

(I)

Crystal data

C11H13NO	F(000) = 188
Mr = 175.22	Dx = 1.245 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 7.7769 (4) Å	Cell parameters from 1140 reflections
b = 6.2492 (3) Å	θ = 1.0–27.5°
c = 9.6263 (5) Å	µ = 0.08 mm^−1
β = 92.749 (2)°	T = 123 K
V = 467.29 (4) Å^3	Needle, colourless
Z = 2	0.60 × 0.10 × 0.04 mm

Data collection

Nonius KappaCCD diffractometer	810 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.051
Graphite monochromator	θmax = 27.5°, θmin = 2.1°
ω and φ scans	h = −9→10
6426 measured reflections	k = −8→8
1163 independent reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.095	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0488P)^2] where P = (Fo^2 + 2Fc^2)/3
1163 reflections	(Δ/σ)max < 0.001
125 parameters	Δρmax = 0.18 e Å^−3
1 restraint	Δρmin = −0.23 e Å^−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. H on N refined isotropically. All others in calc positions and riding modes. The methyl groups were allowed to rotate but not to tip.

Friedel pairs were merged for the final refinement. This made no significant change to the geometric parameters.

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	0.7746 (2)	0.3981 (3)	0.50995 (17)	0.0264 (5)
N1	0.6070 (3)	0.8496 (4)	0.9741 (2)	0.0247 (6)
C1	0.6962 (3)	0.7380 (5)	1.0786 (2)	0.0220 (6)
C2	0.7812 (3)	0.5693 (4)	1.0220 (3)	0.0205 (6)
C3	0.7435 (3)	0.5769 (5)	0.8740 (2)	0.0190 (6)
C4	0.6330 (3)	0.7516 (4)	0.8479 (2)	0.0210 (6)
C5	0.5682 (3)	0.8008 (5)	0.7145 (3)	0.0245 (7)
H5	0.4910	0.9170	0.6985	0.029*
C6	0.6196 (3)	0.6756 (5)	0.6066 (3)	0.0267 (7)
H6	0.5774	0.7061	0.5145	0.032*
C7	0.7330 (3)	0.5042 (4)	0.6299 (3)	0.0210 (7)
C8	0.7953 (3)	0.4500 (4)	0.7620 (2)	0.0207 (7)
H8	0.8705	0.3315	0.7771	0.025*
C9	0.6912 (3)	0.8130 (5)	1.2249 (2)	0.0272 (7)
H9A	0.5716	0.8407	1.2474	0.041*
H9B	0.7584	0.9449	1.2364	0.041*
H9C	0.7401	0.7027	1.2875	0.041*
C10	0.8945 (3)	0.4101 (5)	1.0966 (3)	0.0287 (7)
H10A	0.8855	0.4275	1.1971	0.043*
H10B	1.0140	0.4329	1.0723	0.043*
H10C	0.8584	0.2652	1.0694	0.043*
C11	0.8822 (4)	0.2142 (5)	0.5252 (3)	0.0333 (8)
H11A	0.8252	0.1060	0.5806	0.050*
H11B	0.9919	0.2547	0.5723	0.050*
H11C	0.9035	0.1553	0.4332	0.050*
H1	0.528 (4)	0.961 (6)	0.985 (4)	0.051 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0297 (10)	0.0303 (12)	0.0193 (10)	0.0038 (10)	0.0020 (8)	−0.0053 (9)
N1	0.0277 (13)	0.0252 (15)	0.0210 (13)	0.0070 (12)	−0.0004 (10)	0.0003 (11)
C1	0.0196 (13)	0.0269 (16)	0.0192 (15)	−0.0030 (13)	−0.0013 (11)	−0.0008 (13)
C2	0.0199 (13)	0.0202 (15)	0.0212 (14)	−0.0005 (13)	−0.0007 (10)	0.0013 (13)
C3	0.0168 (12)	0.0210 (14)	0.0191 (14)	−0.0031 (12)	−0.0005 (10)	0.0034 (13)
C4	0.0211 (13)	0.0229 (16)	0.0192 (15)	0.0001 (14)	0.0019 (11)	−0.0005 (13)
C5	0.0265 (15)	0.0231 (16)	0.0238 (15)	0.0051 (14)	−0.0002 (12)	0.0043 (13)
C6	0.0259 (15)	0.0339 (17)	0.0199 (15)	−0.0008 (14)	−0.0023 (12)	0.0017 (14)
C7	0.0201 (13)	0.0244 (16)	0.0188 (15)	−0.0039 (14)	0.0040 (11)	−0.0021 (13)
C8	0.0173 (13)	0.0254 (17)	0.0195 (15)	−0.0003 (12)	0.0008 (11)	0.0000 (13)
C9	0.0318 (15)	0.0285 (16)	0.0216 (14)	0.0017 (14)	0.0023 (12)	−0.0024 (13)
C10	0.0311 (15)	0.0300 (18)	0.0247 (15)	0.0063 (14)	−0.0014 (12)	−0.0011 (14)
C11	0.0401 (17)	0.0319 (19)	0.0277 (16)	0.0004 (16)	0.0002 (13)	−0.0094 (15)

Geometric parameters (Å, º)

O1—C7	1.383 (3)	C6—C7	1.399 (4)
O1—C11	1.425 (3)	C6—H6	0.9500
N1—C1	1.383 (3)	C7—C8	1.381 (3)
N1—C4	1.384 (3)	C8—H8	0.9500
N1—H1	0.94 (4)	C9—H9A	0.9800
C1—C2	1.371 (4)	C9—H9B	0.9800
C1—C9	1.487 (3)	C9—H9C	0.9800
C2—C3	1.441 (4)	C10—H10A	0.9800
C2—C10	1.490 (4)	C10—H10B	0.9800
C3—C4	1.405 (3)	C10—H10C	0.9800
C3—C8	1.412 (4)	C11—H11A	0.9800
C4—C5	1.391 (3)	C11—H11B	0.9800
C5—C6	1.375 (4)	C11—H11C	0.9800
C5—H5	0.9500
C7—O1—C11	117.4 (2)	C8—C7—C6	121.8 (2)
C1—N1—C4	109.0 (2)	O1—C7—C6	113.8 (2)
C1—N1—H1	127 (2)	C7—C8—C3	117.7 (2)
C4—N1—H1	123 (2)	C7—C8—H8	121.2
C2—C1—N1	109.5 (2)	C3—C8—H8	121.2
C2—C1—C9	130.8 (2)	C1—C9—H9A	109.5
N1—C1—C9	119.7 (2)	C1—C9—H9B	109.5
C1—C2—C3	106.8 (2)	H9A—C9—H9B	109.5
C1—C2—C10	127.4 (2)	C1—C9—H9C	109.5
C3—C2—C10	125.9 (2)	H9A—C9—H9C	109.5
C4—C3—C8	119.6 (2)	H9B—C9—H9C	109.5
C4—C3—C2	107.2 (2)	C2—C10—H10A	109.5
C8—C3—C2	133.2 (2)	C2—C10—H10B	109.5
N1—C4—C5	130.6 (2)	H10A—C10—H10B	109.5
N1—C4—C3	107.5 (2)	C2—C10—H10C	109.5
C5—C4—C3	121.9 (2)	H10A—C10—H10C	109.5
C6—C5—C4	117.8 (3)	H10B—C10—H10C	109.5
C6—C5—H5	121.1	O1—C11—H11A	109.5
C4—C5—H5	121.1	O1—C11—H11B	109.5
C5—C6—C7	121.2 (2)	H11A—C11—H11B	109.5
C5—C6—H6	119.4	O1—C11—H11C	109.5
C7—C6—H6	119.4	H11A—C11—H11C	109.5
C8—C7—O1	124.5 (2)	H11B—C11—H11C	109.5
C4—N1—C1—C2	0.5 (3)	C8—C3—C4—C5	1.9 (4)
C4—N1—C1—C9	179.2 (2)	C2—C3—C4—C5	−178.4 (2)
N1—C1—C2—C3	0.2 (3)	N1—C4—C5—C6	178.8 (3)
C9—C1—C2—C3	−178.2 (3)	C3—C4—C5—C6	−1.8 (4)
N1—C1—C2—C10	179.0 (2)	C4—C5—C6—C7	0.1 (4)
C9—C1—C2—C10	0.5 (4)	C11—O1—C7—C8	3.3 (4)
C1—C2—C3—C4	−0.9 (3)	C11—O1—C7—C6	−176.7 (2)
C10—C2—C3—C4	−179.7 (2)	C5—C6—C7—C8	1.4 (4)
C1—C2—C3—C8	178.8 (3)	C5—C6—C7—O1	−178.6 (2)
C10—C2—C3—C8	0.0 (5)	O1—C7—C8—C3	178.7 (2)
C1—N1—C4—C5	178.4 (3)	C6—C7—C8—C3	−1.3 (4)
C1—N1—C4—C3	−1.1 (3)	C4—C3—C8—C7	−0.3 (4)
C8—C3—C4—N1	−178.6 (2)	C2—C3—C8—C7	−180.0 (3)
C2—C3—C4—N1	1.2 (3)