1-Acetyl-2-oxo-4′-methyl-2a′-phenyl­spiro­[3H-indole-3,2′(2a′H,5a′H)-oxeto­[3,2-d]­oxazole]

In the title compound, C₂₀H₁₆N₂O₄, the oxetane and oxazoline rings are almost planar, while the heterocyclic ring of the indole moiety is distorted from planarity towards an envelope conformation. The phenyl ring is in a +sp conformation with respect to the indole moiety. The packing is stabilized by intermolecular C—H...O and C—H...π interactions, as well as dipole–dipole and van der Waals interactions.

Key indicators

• Single-crystal X-ray study
• T = 183 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.073
• wR factor = 0.192
• Data-to-parameter ratio = 12.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 1990).

1-Acetyl-2-oxo-4'-methyl-2'a-phenylspiro[3H-indole-3,2'(2'aH,5'aH)oxeto [3,2-d]oxazole]

Crystal data

C20H16N2O4	F(000) = 364
Mr = 348.35	Dx = 1.383 Mg m^−3
Triclinic, P1	Melting point: 424K K
a = 9.2852 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.5994 (4) Å	Cell parameters from 3902 reflections
c = 10.6206 (5) Å	θ = 2.7–28.3°
α = 67.323 (1)°	µ = 0.10 mm^−1
β = 73.287 (1)°	T = 183 K
γ = 84.761 (1)°	Block, colorless
V = 836.36 (6) Å^3	0.40 × 0.40 × 0.36 mm
Z = 2

Data collection

Siemens SMART CCD area-detector diffractometer	2870 independent reflections
Radiation source: fine-focus sealed tube	2245 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.056
Detector resolution: 8.33 pixels mm^-1	θmax = 25.0°, θmin = 2.7°
ω scans	h = −9→11
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −11→8
Tmin = 0.962, Tmax = 0.966	l = −12→12
4078 measured 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)] = 0.073	H-atom parameters constrained
wR(F^2) = 0.192	w = 1/[σ^2(Fo^2) + (0.1195P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max < 0.001
2870 reflections	Δρmax = 0.46 e Å^−3
238 parameters	Δρmin = −0.41 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: 0.078 (14)

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different φ angle (0, 88 and 180°) for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal-to-detector distance was 5 cm and the detector swing angle was -35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the intensity of duplicate reflections, and was found to be negligible.

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
O1	0.73162 (18)	0.46115 (18)	0.17428 (18)	0.0269 (5)
O2	0.4581 (3)	0.8073 (2)	0.2535 (3)	0.0659 (8)
O3	0.59034 (17)	0.17230 (17)	0.38008 (17)	0.0226 (4)
O4	0.68861 (17)	0.09000 (18)	0.18859 (17)	0.0242 (5)
N1	0.5148 (2)	0.5662 (2)	0.2788 (2)	0.0246 (5)
N2	0.5650 (2)	0.2937 (2)	0.0733 (2)	0.0193 (5)
C1	0.3804 (3)	0.4986 (3)	0.3896 (3)	0.0260 (6)
C2	0.2673 (3)	0.5662 (3)	0.4634 (3)	0.0373 (7)
H2	0.2694	0.6694	0.4430	0.045*
C3	0.1508 (3)	0.4725 (4)	0.5693 (3)	0.0448 (8)
H3	0.0729	0.5147	0.6197	0.054*
C4	0.1478 (3)	0.3191 (4)	0.6014 (3)	0.0412 (8)
H4	0.0688	0.2596	0.6733	0.049*
C5	0.2614 (3)	0.2524 (3)	0.5277 (3)	0.0298 (6)
H5	0.2598	0.1490	0.5490	0.036*
C6	0.3779 (3)	0.3446 (3)	0.4210 (2)	0.0221 (6)
C7	0.5068 (2)	0.3057 (2)	0.3206 (2)	0.0178 (5)
C8	0.6032 (2)	0.4503 (3)	0.2458 (2)	0.0195 (5)
C9	0.5495 (3)	0.7224 (3)	0.2165 (3)	0.0353 (7)
C10	0.6952 (4)	0.7772 (3)	0.1085 (3)	0.0434 (8)
H10A	0.7758	0.7253	0.1465	0.065*
H10B	0.7067	0.8837	0.0833	0.065*
H10C	0.6976	0.7579	0.0257	0.065*
C11	0.4711 (2)	0.2319 (2)	0.2206 (2)	0.0169 (5)
C12	0.5591 (2)	0.0973 (3)	0.2963 (2)	0.0203 (5)
H12	0.5007	0.0025	0.3511	0.024*
C13	0.6799 (2)	0.2101 (3)	0.0673 (3)	0.0219 (6)
C14	0.8079 (3)	0.2259 (3)	−0.0594 (3)	0.0360 (7)
H14A	0.8187	0.1334	−0.0757	0.054*
H14B	0.8986	0.2479	−0.0437	0.054*
H14C	0.7894	0.3067	−0.1407	0.054*
C15	0.3073 (2)	0.2197 (2)	0.2306 (2)	0.0182 (5)
C16	0.2345 (3)	0.3512 (3)	0.1696 (2)	0.0226 (6)
H16	0.2876	0.4428	0.1218	0.027*
C17	0.0826 (3)	0.3456 (3)	0.1801 (3)	0.0297 (6)
H17	0.0340	0.4335	0.1389	0.036*
C18	0.0033 (3)	0.2098 (3)	0.2516 (3)	0.0377 (7)
H18	−0.0990	0.2063	0.2599	0.045*
C19	0.0760 (3)	0.0794 (3)	0.3105 (3)	0.0416 (8)
H19	0.0230	−0.0123	0.3568	0.050*
C20	0.2277 (3)	0.0836 (3)	0.3011 (3)	0.0300 (6)
H20	0.2758	−0.0046	0.3421	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0166 (9)	0.0277 (10)	0.0353 (10)	−0.0007 (7)	−0.0047 (7)	−0.0122 (8)
O2	0.0579 (15)	0.0337 (13)	0.111 (2)	0.0080 (10)	−0.0115 (15)	−0.0426 (14)
O3	0.0201 (9)	0.0217 (9)	0.0265 (9)	0.0072 (6)	−0.0113 (7)	−0.0074 (7)
O4	0.0169 (9)	0.0225 (9)	0.0309 (9)	0.0059 (6)	−0.0039 (7)	−0.0106 (8)
N1	0.0237 (11)	0.0241 (11)	0.0332 (12)	0.0061 (8)	−0.0101 (9)	−0.0179 (10)
N2	0.0161 (10)	0.0198 (10)	0.0209 (10)	−0.0001 (7)	−0.0015 (8)	−0.0089 (8)
C1	0.0218 (13)	0.0373 (15)	0.0290 (13)	0.0074 (10)	−0.0125 (10)	−0.0205 (12)
C2	0.0298 (15)	0.0510 (18)	0.0466 (16)	0.0159 (12)	−0.0156 (13)	−0.0345 (15)
C3	0.0271 (16)	0.076 (2)	0.0423 (17)	0.0197 (14)	−0.0077 (13)	−0.0396 (17)
C4	0.0202 (14)	0.073 (2)	0.0304 (14)	0.0022 (13)	0.0007 (11)	−0.0247 (15)
C5	0.0205 (13)	0.0432 (16)	0.0241 (12)	0.0028 (10)	−0.0057 (10)	−0.0115 (12)
C6	0.0168 (12)	0.0327 (14)	0.0213 (11)	0.0063 (9)	−0.0086 (10)	−0.0136 (11)
C7	0.0140 (11)	0.0187 (12)	0.0206 (11)	0.0039 (8)	−0.0062 (9)	−0.0071 (10)
C8	0.0172 (12)	0.0222 (12)	0.0253 (12)	0.0070 (9)	−0.0112 (10)	−0.0131 (10)
C9	0.0422 (16)	0.0269 (14)	0.0501 (17)	0.0042 (11)	−0.0192 (13)	−0.0247 (13)
C10	0.067 (2)	0.0255 (15)	0.0408 (16)	−0.0075 (13)	−0.0101 (15)	−0.0178 (13)
C11	0.0148 (11)	0.0147 (11)	0.0202 (11)	0.0011 (8)	−0.0029 (9)	−0.0071 (9)
C12	0.0132 (11)	0.0202 (12)	0.0259 (12)	0.0021 (8)	−0.0024 (9)	−0.0093 (10)
C13	0.0147 (12)	0.0224 (12)	0.0297 (13)	0.0007 (9)	−0.0034 (10)	−0.0130 (11)
C14	0.0263 (15)	0.0375 (16)	0.0385 (15)	−0.0001 (11)	0.0053 (12)	−0.0184 (13)
C15	0.0137 (12)	0.0208 (12)	0.0221 (11)	0.0019 (8)	−0.0056 (9)	−0.0100 (10)
C16	0.0194 (13)	0.0224 (13)	0.0267 (12)	0.0033 (9)	−0.0076 (10)	−0.0096 (10)
C17	0.0218 (14)	0.0396 (16)	0.0358 (14)	0.0124 (11)	−0.0149 (11)	−0.0202 (13)
C18	0.0149 (13)	0.0527 (19)	0.0547 (18)	0.0023 (12)	−0.0114 (12)	−0.0291 (15)
C19	0.0232 (15)	0.0382 (17)	0.063 (2)	−0.0093 (11)	−0.0061 (13)	−0.0200 (15)
C20	0.0209 (14)	0.0213 (13)	0.0454 (16)	0.0005 (10)	−0.0094 (12)	−0.0097 (12)

Geometric parameters (Å, º)

O1—C8	1.204 (3)	C7—C11	1.602 (3)
O2—C9	1.212 (3)	C9—C10	1.482 (4)
O3—C12	1.441 (3)	C10—H10A	0.9600
O3—C7	1.455 (3)	C10—H10B	0.9600
O4—C13	1.376 (3)	C10—H10C	0.9600
O4—C12	1.420 (3)	C11—C15	1.506 (3)
N1—C9	1.410 (3)	C11—C12	1.539 (3)
N1—C8	1.415 (3)	C12—H12	0.9800
N1—C1	1.441 (3)	C13—C14	1.484 (3)
N2—C13	1.277 (3)	C14—H14A	0.9600
N2—C11	1.467 (3)	C14—H14B	0.9600
C1—C6	1.385 (3)	C14—H14C	0.9600
C1—C2	1.390 (4)	C15—C20	1.385 (3)
C2—C3	1.394 (4)	C15—C16	1.391 (3)
C2—H2	0.9300	C16—C17	1.387 (3)
C3—C4	1.379 (5)	C16—H16	0.9300
C3—H3	0.9300	C17—C18	1.382 (4)
C4—C5	1.387 (4)	C17—H17	0.9300
C4—H4	0.9300	C18—C19	1.378 (4)
C5—C6	1.390 (4)	C18—H18	0.9300
C5—H5	0.9300	C19—C20	1.386 (4)
C6—C7	1.483 (3)	C19—H19	0.9300
C7—C8	1.525 (3)	C20—H20	0.9300
C12—O3—C7	93.58 (16)	H10B—C10—H10C	109.5
C13—O4—C12	105.75 (17)	N2—C11—C15	112.57 (18)
C9—N1—C8	126.9 (2)	N2—C11—C12	104.68 (17)
C9—N1—C1	124.5 (2)	C15—C11—C12	122.67 (19)
C8—N1—C1	108.56 (19)	N2—C11—C7	113.69 (17)
C13—N2—C11	106.19 (19)	C15—C11—C7	115.81 (17)
C6—C1—C2	121.4 (3)	C12—C11—C7	84.42 (16)
C6—C1—N1	109.6 (2)	O4—C12—O3	112.16 (17)
C2—C1—N1	129.0 (2)	O4—C12—C11	104.95 (17)
C1—C2—C3	117.1 (3)	O3—C12—C11	92.51 (15)
C1—C2—H2	121.5	O4—C12—H12	114.9
C3—C2—H2	121.5	O3—C12—H12	114.9
C4—C3—C2	121.8 (3)	C11—C12—H12	114.9
C4—C3—H3	119.1	N2—C13—O4	118.4 (2)
C2—C3—H3	119.1	N2—C13—C14	126.9 (2)
C3—C4—C5	120.7 (3)	O4—C13—C14	114.7 (2)
C3—C4—H4	119.6	C13—C14—H14A	109.5
C5—C4—H4	119.6	C13—C14—H14B	109.5
C4—C5—C6	118.1 (3)	H14A—C14—H14B	109.5
C4—C5—H5	120.9	C13—C14—H14C	109.5
C6—C5—H5	120.9	H14A—C14—H14C	109.5
C1—C6—C5	120.9 (2)	H14B—C14—H14C	109.5
C1—C6—C7	109.6 (2)	C20—C15—C16	119.8 (2)
C5—C6—C7	129.4 (2)	C20—C15—C11	122.1 (2)
O3—C7—C6	117.03 (18)	C16—C15—C11	118.1 (2)
O3—C7—C8	113.24 (18)	C17—C16—C15	120.0 (2)
C6—C7—C8	103.22 (18)	C17—C16—H16	120.0
O3—C7—C11	89.46 (15)	C15—C16—H16	120.0
C6—C7—C11	117.94 (18)	C18—C17—C16	120.1 (2)
C8—C7—C11	116.41 (17)	C18—C17—H17	120.0
O1—C8—N1	127.1 (2)	C16—C17—H17	120.0
O1—C8—C7	125.5 (2)	C19—C18—C17	119.8 (2)
N1—C8—C7	107.33 (19)	C19—C18—H18	120.1
O2—C9—N1	118.4 (3)	C17—C18—H18	120.1
O2—C9—C10	122.3 (3)	C18—C19—C20	120.6 (2)
N1—C9—C10	119.3 (2)	C18—C19—H19	119.7
C9—C10—H10A	109.5	C20—C19—H19	119.7
C9—C10—H10B	109.5	C15—C20—C19	119.8 (2)
H10A—C10—H10B	109.5	C15—C20—H20	120.1
C9—C10—H10C	109.5	C19—C20—H20	120.1
H10A—C10—H10C	109.5
C9—N1—C1—C6	176.8 (2)	C13—N2—C11—C12	0.8 (2)
C8—N1—C1—C6	−3.6 (3)	C13—N2—C11—C7	91.1 (2)
C9—N1—C1—C2	−5.3 (4)	O3—C7—C11—N2	−102.20 (18)
C8—N1—C1—C2	174.3 (2)	C6—C7—C11—N2	137.2 (2)
C6—C1—C2—C3	−0.6 (4)	C8—C7—C11—N2	13.6 (3)
N1—C1—C2—C3	−178.2 (2)	O3—C7—C11—C15	125.13 (19)
C1—C2—C3—C4	0.8 (4)	C6—C7—C11—C15	4.5 (3)
C2—C3—C4—C5	−0.5 (4)	C8—C7—C11—C15	−119.0 (2)
C3—C4—C5—C6	0.0 (4)	O3—C7—C11—C12	1.41 (15)
C2—C1—C6—C5	0.1 (4)	C6—C7—C11—C12	−119.2 (2)
N1—C1—C6—C5	178.1 (2)	C8—C7—C11—C12	117.25 (19)
C2—C1—C6—C7	176.7 (2)	C13—O4—C12—O3	−96.6 (2)
N1—C1—C6—C7	−5.2 (3)	C13—O4—C12—C11	2.5 (2)
C4—C5—C6—C1	0.2 (4)	C7—O3—C12—O4	108.82 (19)
C4—C5—C6—C7	−175.7 (2)	C7—O3—C12—C11	1.56 (16)
C12—O3—C7—C6	119.91 (19)	N2—C11—C12—O4	−2.1 (2)
C12—O3—C7—C8	−120.19 (18)	C15—C11—C12—O4	127.6 (2)
C12—O3—C7—C11	−1.50 (16)	C7—C11—C12—O4	−115.15 (17)
C1—C6—C7—O3	136.3 (2)	N2—C11—C12—O3	111.64 (16)
C5—C6—C7—O3	−47.5 (3)	C15—C11—C12—O3	−118.6 (2)
C1—C6—C7—C8	11.2 (2)	C7—C11—C12—O3	−1.42 (15)
C5—C6—C7—C8	−172.6 (2)	C11—N2—C13—O4	0.9 (3)
C1—C6—C7—C11	−118.8 (2)	C11—N2—C13—C14	179.8 (2)
C5—C6—C7—C11	57.5 (3)	C12—O4—C13—N2	−2.3 (3)
C9—N1—C8—O1	11.3 (4)	C12—O4—C13—C14	178.67 (19)
C1—N1—C8—O1	−168.3 (2)	N2—C11—C15—C20	121.9 (2)
C9—N1—C8—C7	−169.8 (2)	C12—C11—C15—C20	−4.4 (3)
C1—N1—C8—C7	10.6 (2)	C7—C11—C15—C20	−104.9 (2)
O3—C7—C8—O1	38.2 (3)	N2—C11—C15—C16	−59.8 (3)
C6—C7—C8—O1	165.7 (2)	C12—C11—C15—C16	173.90 (19)
C11—C7—C8—O1	−63.4 (3)	C7—C11—C15—C16	73.4 (3)
O3—C7—C8—N1	−140.62 (18)	C20—C15—C16—C17	0.2 (3)
C6—C7—C8—N1	−13.1 (2)	C11—C15—C16—C17	−178.1 (2)
C11—C7—C8—N1	117.7 (2)	C15—C16—C17—C18	0.3 (4)
C8—N1—C9—O2	177.2 (3)	C16—C17—C18—C19	−1.1 (4)
C1—N1—C9—O2	−3.3 (4)	C17—C18—C19—C20	1.3 (4)
C8—N1—C9—C10	−2.7 (4)	C16—C15—C20—C19	0.0 (4)
C1—N1—C9—C10	176.9 (2)	C11—C15—C20—C19	178.3 (2)
C13—N2—C11—C15	−134.7 (2)	C18—C19—C20—C15	−0.8 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O2	0.93	2.28	2.822 (4)	116
C10—H10B···O4^i	0.96	2.60	3.413 (4)	143
C12—H12···O2^ii	0.98	2.57	3.246 (4)	126
C10—H10C···Cg^iii	0.96	2.68	3.538 (4)	148

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