(Z)-1,3,4a-Trimethyl-5,5-diphenyl-6-oxa-1,3-diaza­bicyclo­[4.2.0]octane-2,4-dione

Lin, Z.-C.; Shi, J.-B.; Tang, W.-J.; Li, J.

doi:10.1107/S1600536808006557

organic compounds

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ISSN: 2056-9890

Volume 64| Part 5| May 2008| Page o796

doi:10.1107/S1600536808006557

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(Z)-1,3,4a-Trimethyl-5,5-diphenyl-6-oxa-1,3-diazabicyclo[4.2.0]octane-2,4-dione

Zhi-Cai Lin,^a Jing-Bo Shi,^a Wen-Jian Tang ^a ^* and Jun Li ^a

^aSchool of Pharmacy, Anhui Medical University, Hefei 230032, People's Republic of China
^*Correspondence e-mail: tangwjster@gmail.com

(Received 23 January 2008; accepted 8 March 2008; online 4 April 2008)

The title compound, C₂₀H₂₀N₂O₃, is a head-to-tail oxetane, one of the regioisomers obtained by the the Paternó–Büchi reaction of 1,3-dimethylthymine with benzophenone. The oxetane ring is folded, the dihedral angle between the C—O—C and C—C—C planes being 14.4 (2)°. The dihedral angle between the two phenyl rings is 64.3 (2)°. The pyrimidine ring adopts a boat conformation. The crystal structure involves weak C—H⋯O hydrogen bonds.

Related literature

For related literature, see: Hei et al. (2005 ); Prakash et al. (1997 ).

Experimental

Crystal data

C₂₀H₂₀N₂O₃
M_r = 336.38
Monoclinic, P 2₁ /n
a = 8.1341 (7) Å
b = 9.1004 (13) Å
c = 23.485 (2) Å
β = 97.334 (2)°
V = 1724.2 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 (2) K
0.45 × 0.41 × 0.18 mm

Data collection

Bruker SMART diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.962, T_max = 0.984
8774 measured reflections
3039 independent reflections
1818 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.117
S = 1.01
3039 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2ⁱ	0.98	2.53	3.431 (3)	153
C7—H7⋯O1	0.93	2.37	2.745 (3)	104
C8—H8⋯O1ⁱⁱ	0.93	2.59	3.513 (3)	171
C13—H13⋯O1	0.93	2.41	2.752 (3)	101
C17—H17⋯O3	0.93	2.55	3.040 (3)	113
C20—H20B⋯O2	0.96	2.29	2.682 (4)	104
Symmetry codes: (i) $[-x+{\script{5\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Siemens, 1996 ); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808006557/wn2239sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808006557/wn2239Isup2.hkl

checkCIF report

Comment top

A [2 + 2] photocycloaddition (Paternò-Büchi reaction) of the 5–6 double bond of 1,3-dimethylthymine (DMT) with the carbonyl of benzophenone generates two regioisomers, head-to-head and head-to-tail oxetanes (Fig. 1). We have observed the temperature dependence of the regioselectivity (Hei et al., 2005). The crystal structure of the head-to-head oxetane has already been published (Prakash et al., 1997). In the present study, an X-ray crystallographic analysis of the head-to-tail oxetane has been undertaken to establish its structure and configuration.

The structure is similar to that observed in the head-to-head oxetane (Prakash et al., 1997). The bond lengths and angles in the title compound are in good agreement with expected values. The oxetane ring is folded and the dihedral angle between the C1—O1—C3 and C1—C2—C3 planes is 14.4 (2)° (Fig. 2). The dihedral angle between the two phenyl rings is 64.3 (2)° and the pyrimidine ring adopts a boat conformation. The crystal structure involves weak C—H···O hydrogen bonds.

Related literature top

For related literature, see: Hei et al. (2005); Prakash et al. (1997).

Experimental top

The title compound was prepared by first dissolving DMT (0.77 g, 5.0 mmol) and benzophenone (1.82 g, 10.0 mmol) in CH₃CN (100 ml). The resulting solution was placed in a photochemical apparatus (Pyrex), purged with nitrogen, degassed for 30 min, and irradiated with a 300 W mercury high-pressure lamp for 10 h. The solvent was then rotary evaporated and the oxetane was purified by silica gel chromatography using a 4:1 petroleum ether/ethyl acetate solvent mixture. The fractions containing the h-t oxetane were combined, and the solvent removed by rotary evaporation. The purified oxetane was subsequently crystallized by dissolving the residue in 10 ml of ethyl acetate and adding n-hexane to the solution until it turned cloudy. Upon standing at room temperature, a colorless block appeared and was separated from the solvent by decanting.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Formation of the two regioisomers of the Paternó-Büchi reaction.
	Fig. 2. Molecular structure of the title compound, with the atomic numbering scheme, and displacement ellipsoids drawn at the 30% probability level.

(Z)-1,3,4a-Trimethyl-5,5-diphenyl-6-oxa-1,3-diazabicyclo[4.2.0]octane- 2,4-dione top

Crystal data top

C₂₀H₂₀N₂O₃	F(000) = 712
M_r = 336.38	D_x = 1.296 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 8.1341 (7) Å	Cell parameters from 1952 reflections
b = 9.1004 (13) Å	θ = 2.4–22.1°
c = 23.485 (2) Å	µ = 0.09 mm⁻¹
β = 97.334 (2)°	T = 298 K
V = 1724.2 (3) Å³	Block, colorless
Z = 4	0.45 × 0.41 × 0.18 mm

Data collection top

Bruker SMART diffractometer	3039 independent reflections
Radiation source: fine-focus sealed tube	1818 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.036
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
T_min = 0.962, T_max = 0.984	k = −10→10
8774 measured reflections	l = −24→27

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.117	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.038P)² + 0.7238P] where P = (F_o² + 2F_c²)/3
3039 reflections	(Δ/σ)_max < 0.001
226 parameters	Δρ_max = 0.20 e Å⁻³
0 restraints	Δρ_min = −0.18 e Å⁻³

Crystal data top

C₂₀H₂₀N₂O₃	V = 1724.2 (3) Å³
M_r = 336.38	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.1341 (7) Å	µ = 0.09 mm⁻¹
b = 9.1004 (13) Å	T = 298 K
c = 23.485 (2) Å	0.45 × 0.41 × 0.18 mm
β = 97.334 (2)°

Data collection top

Bruker SMART diffractometer	3039 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1818 reflections with I > 2σ(I)
T_min = 0.962, T_max = 0.984	R_int = 0.036
8774 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.117	H-atom parameters constrained
S = 1.01	Δρ_max = 0.20 e Å⁻³
3039 reflections	Δρ_min = −0.18 e Å⁻³
226 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
N1	1.2692 (2)	0.5663 (2)	0.21196 (8)	0.0491 (5)
N2	1.2831 (2)	0.6885 (2)	0.12510 (8)	0.0492 (5)
O1	0.97763 (19)	0.60800 (17)	0.19685 (6)	0.0469 (4)
O2	1.4490 (2)	0.7527 (2)	0.20642 (8)	0.0750 (6)
O3	1.1732 (2)	0.5833 (2)	0.04218 (7)	0.0625 (5)
C1	0.9036 (3)	0.5849 (2)	0.13794 (8)	0.0379 (5)
C2	1.0673 (3)	0.4991 (2)	0.12589 (9)	0.0380 (5)
C3	1.1126 (3)	0.5076 (3)	0.19078 (9)	0.0427 (6)
H3	1.0949	0.4127	0.2088	0.051*
C4	1.3391 (3)	0.6743 (3)	0.18356 (11)	0.0503 (6)
C5	1.1782 (3)	0.5906 (3)	0.09400 (10)	0.0440 (6)
C6	0.7544 (3)	0.4834 (2)	0.13563 (9)	0.0398 (6)
C7	0.7166 (3)	0.4145 (3)	0.18451 (11)	0.0555 (7)
H7	0.7781	0.4358	0.2197	0.067*
C8	0.5890 (4)	0.3147 (3)	0.18183 (13)	0.0654 (8)
H8	0.5646	0.2695	0.2153	0.079*
C9	0.4977 (3)	0.2812 (3)	0.13056 (13)	0.0617 (8)
H9	0.4128	0.2124	0.1289	0.074*
C10	0.5325 (3)	0.3502 (3)	0.08148 (12)	0.0580 (7)
H10	0.4701	0.3289	0.0465	0.070*
C11	0.6592 (3)	0.4506 (3)	0.08398 (10)	0.0481 (6)
H11	0.6815	0.4971	0.0506	0.058*
C12	0.8626 (3)	0.7299 (2)	0.10882 (9)	0.0385 (6)
C13	0.8285 (3)	0.8494 (3)	0.14167 (11)	0.0505 (6)
H13	0.8336	0.8392	0.1813	0.061*
C14	0.7872 (4)	0.9835 (3)	0.11655 (14)	0.0673 (8)
H14	0.7645	1.0629	0.1392	0.081*
C15	0.7794 (4)	0.9999 (3)	0.05856 (14)	0.0727 (9)
H15	0.7523	1.0906	0.0417	0.087*
C16	0.8116 (4)	0.8830 (3)	0.02531 (12)	0.0666 (8)
H16	0.8061	0.8942	−0.0142	0.080*
C17	0.8520 (3)	0.7485 (3)	0.05001 (10)	0.0504 (6)
H17	0.8724	0.6693	0.0269	0.060*
C18	1.0451 (3)	0.3473 (3)	0.09951 (10)	0.0503 (6)
H18A	0.9886	0.3552	0.0612	0.075*
H18B	0.9809	0.2877	0.1222	0.075*
H18C	1.1517	0.3029	0.0985	0.075*
C19	1.3263 (4)	0.5493 (3)	0.27297 (11)	0.0783 (9)
H19A	1.4432	0.5683	0.2799	0.117*
H19B	1.3046	0.4508	0.2847	0.117*
H19C	1.2686	0.6175	0.2945	0.117*
C20	1.3705 (4)	0.7944 (3)	0.09317 (13)	0.0803 (10)
H20A	1.4539	0.7445	0.0751	0.121*
H20B	1.4218	0.8676	0.1190	0.121*
H20C	1.2931	0.8408	0.0644	0.121*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0490 (13)	0.0549 (13)	0.0392 (12)	0.0034 (11)	−0.0110 (9)	−0.0031 (10)
N2	0.0448 (12)	0.0524 (13)	0.0499 (13)	−0.0048 (10)	0.0035 (10)	−0.0005 (10)
O1	0.0509 (10)	0.0554 (11)	0.0329 (9)	0.0088 (8)	−0.0009 (7)	−0.0072 (7)
O2	0.0666 (13)	0.0819 (14)	0.0730 (13)	−0.0225 (12)	−0.0044 (11)	−0.0256 (11)
O3	0.0560 (12)	0.0921 (14)	0.0402 (11)	−0.0015 (10)	0.0092 (8)	−0.0015 (9)
C1	0.0403 (14)	0.0433 (14)	0.0290 (12)	0.0050 (11)	0.0004 (10)	−0.0041 (10)
C2	0.0387 (13)	0.0403 (13)	0.0336 (12)	0.0042 (11)	−0.0008 (10)	−0.0043 (10)
C3	0.0467 (15)	0.0395 (14)	0.0402 (14)	0.0043 (12)	−0.0011 (11)	−0.0030 (11)
C4	0.0450 (15)	0.0526 (17)	0.0519 (16)	0.0041 (13)	0.0012 (13)	−0.0122 (13)
C5	0.0377 (14)	0.0522 (16)	0.0414 (15)	0.0069 (12)	0.0024 (11)	−0.0021 (12)
C6	0.0379 (13)	0.0414 (14)	0.0405 (14)	0.0063 (11)	0.0067 (11)	0.0006 (11)
C7	0.0573 (17)	0.0665 (18)	0.0442 (15)	−0.0029 (15)	0.0119 (12)	0.0020 (13)
C8	0.0656 (19)	0.070 (2)	0.065 (2)	−0.0033 (16)	0.0253 (16)	0.0127 (15)
C9	0.0438 (16)	0.0573 (18)	0.085 (2)	−0.0021 (14)	0.0134 (15)	0.0074 (16)
C10	0.0402 (15)	0.0623 (18)	0.0680 (19)	−0.0026 (14)	−0.0062 (13)	0.0037 (15)
C11	0.0447 (15)	0.0519 (16)	0.0467 (15)	−0.0002 (13)	0.0015 (12)	0.0076 (12)
C12	0.0324 (13)	0.0391 (14)	0.0434 (14)	0.0010 (10)	0.0027 (10)	−0.0035 (11)
C13	0.0477 (15)	0.0505 (16)	0.0512 (15)	0.0059 (13)	−0.0016 (12)	−0.0098 (13)
C14	0.073 (2)	0.0418 (16)	0.083 (2)	0.0119 (14)	−0.0031 (16)	−0.0150 (15)
C15	0.087 (2)	0.0434 (17)	0.083 (2)	0.0064 (15)	−0.0078 (18)	0.0103 (16)
C16	0.089 (2)	0.0519 (18)	0.0564 (17)	0.0058 (16)	−0.0001 (15)	0.0085 (14)
C17	0.0587 (17)	0.0438 (15)	0.0483 (16)	0.0068 (13)	0.0059 (12)	0.0010 (12)
C18	0.0462 (15)	0.0501 (15)	0.0524 (15)	0.0065 (12)	−0.0026 (12)	−0.0129 (12)
C19	0.082 (2)	0.095 (2)	0.0493 (17)	−0.0024 (19)	−0.0221 (15)	0.0001 (16)
C20	0.078 (2)	0.082 (2)	0.082 (2)	−0.0240 (18)	0.0150 (18)	0.0105 (17)

Geometric parameters (Å, º) top

N1—C4	1.353 (3)	C9—H9	0.9300
N1—C3	1.412 (3)	C10—C11	1.373 (3)
N1—C19	1.457 (3)	C10—H10	0.9300
N2—C5	1.377 (3)	C11—H11	0.9300
N2—C4	1.396 (3)	C12—C13	1.381 (3)
N2—C20	1.460 (3)	C12—C17	1.383 (3)
O1—C3	1.450 (3)	C13—C14	1.379 (4)
O1—C1	1.452 (2)	C13—H13	0.9300
O2—C4	1.214 (3)	C14—C15	1.364 (4)
O3—C5	1.214 (3)	C14—H14	0.9300
C1—C12	1.504 (3)	C15—C16	1.365 (4)
C1—C6	1.521 (3)	C15—H15	0.9300
C1—C2	1.600 (3)	C16—C17	1.376 (3)
C2—C5	1.497 (3)	C16—H16	0.9300
C2—C18	1.515 (3)	C17—H17	0.9300
C2—C3	1.523 (3)	C18—H18A	0.9600
C3—H3	0.9800	C18—H18B	0.9600
C6—C7	1.376 (3)	C18—H18C	0.9600
C6—C11	1.386 (3)	C19—H19A	0.9600
C7—C8	1.375 (4)	C19—H19B	0.9600
C7—H7	0.9300	C19—H19C	0.9600
C8—C9	1.366 (4)	C20—H20A	0.9600
C8—H8	0.9300	C20—H20B	0.9600
C9—C10	1.373 (4)	C20—H20C	0.9600

C4—N1—C3	121.2 (2)	C11—C10—C9	120.2 (3)
C4—N1—C19	117.4 (2)	C11—C10—H10	119.9
C3—N1—C19	117.8 (2)	C9—C10—H10	119.9
C5—N2—C4	124.3 (2)	C10—C11—C6	120.9 (2)
C5—N2—C20	117.6 (2)	C10—C11—H11	119.6
C4—N2—C20	116.6 (2)	C6—C11—H11	119.6
C3—O1—C1	92.41 (14)	C13—C12—C17	118.0 (2)
O1—C1—C12	110.28 (17)	C13—C12—C1	119.0 (2)
O1—C1—C6	110.74 (17)	C17—C12—C1	122.9 (2)
C12—C1—C6	112.78 (18)	C14—C13—C12	120.9 (2)
O1—C1—C2	89.20 (14)	C14—C13—H13	119.6
C12—C1—C2	119.28 (18)	C12—C13—H13	119.6
C6—C1—C2	112.08 (17)	C15—C14—C13	120.1 (3)
C5—C2—C18	110.54 (19)	C15—C14—H14	119.9
C5—C2—C3	112.83 (19)	C13—C14—H14	119.9
C18—C2—C3	117.16 (19)	C14—C15—C16	119.9 (3)
C5—C2—C1	112.63 (18)	C14—C15—H15	120.1
C18—C2—C1	117.30 (18)	C16—C15—H15	120.1
C3—C2—C1	84.20 (15)	C15—C16—C17	120.3 (3)
N1—C3—O1	112.77 (18)	C15—C16—H16	119.8
N1—C3—C2	117.63 (19)	C17—C16—H16	119.8
O1—C3—C2	92.34 (15)	C16—C17—C12	120.7 (2)
N1—C3—H3	110.9	C16—C17—H17	119.6
O1—C3—H3	110.9	C12—C17—H17	119.6
C2—C3—H3	110.9	C2—C18—H18A	109.5
O2—C4—N1	122.7 (2)	C2—C18—H18B	109.5
O2—C4—N2	120.6 (3)	H18A—C18—H18B	109.5
N1—C4—N2	116.6 (2)	C2—C18—H18C	109.5
O3—C5—N2	120.4 (2)	H18A—C18—H18C	109.5
O3—C5—C2	121.7 (2)	H18B—C18—H18C	109.5
N2—C5—C2	117.8 (2)	N1—C19—H19A	109.5
C7—C6—C11	118.2 (2)	N1—C19—H19B	109.5
C7—C6—C1	120.6 (2)	H19A—C19—H19B	109.5
C11—C6—C1	121.07 (19)	N1—C19—H19C	109.5
C8—C7—C6	120.7 (2)	H19A—C19—H19C	109.5
C8—C7—H7	119.7	H19B—C19—H19C	109.5
C6—C7—H7	119.7	N2—C20—H20A	109.5
C9—C8—C7	120.7 (3)	N2—C20—H20B	109.5
C9—C8—H8	119.7	H20A—C20—H20B	109.5
C7—C8—H8	119.7	N2—C20—H20C	109.5
C8—C9—C10	119.4 (3)	H20A—C20—H20C	109.5
C8—C9—H9	120.3	H20B—C20—H20C	109.5
C10—C9—H9	120.3

C3—O1—C1—C12	−131.48 (18)	C20—N2—C5—C2	−170.0 (2)
C3—O1—C1—C6	102.98 (19)	C18—C2—C5—O3	37.6 (3)
C3—O1—C1—C2	−10.39 (16)	C3—C2—C5—O3	170.9 (2)
O1—C1—C2—C5	−102.41 (19)	C1—C2—C5—O3	−95.8 (3)
C12—C1—C2—C5	10.5 (3)	C18—C2—C5—N2	−144.8 (2)
C6—C1—C2—C5	145.47 (19)	C3—C2—C5—N2	−11.4 (3)
O1—C1—C2—C18	127.57 (19)	C1—C2—C5—N2	81.9 (2)
C12—C1—C2—C18	−119.5 (2)	O1—C1—C6—C7	−6.9 (3)
C6—C1—C2—C18	15.5 (3)	C12—C1—C6—C7	−131.1 (2)
O1—C1—C2—C3	9.93 (15)	C2—C1—C6—C7	91.0 (2)
C12—C1—C2—C3	122.9 (2)	O1—C1—C6—C11	177.12 (19)
C6—C1—C2—C3	−102.19 (18)	C12—C1—C6—C11	53.0 (3)
C4—N1—C3—O1	−72.4 (3)	C2—C1—C6—C11	−85.0 (2)
C19—N1—C3—O1	85.8 (3)	C11—C6—C7—C8	0.7 (4)
C4—N1—C3—C2	33.3 (3)	C1—C6—C7—C8	−175.3 (2)
C19—N1—C3—C2	−168.6 (2)	C6—C7—C8—C9	0.3 (4)
C1—O1—C3—N1	132.30 (19)	C7—C8—C9—C10	−1.1 (4)
C1—O1—C3—C2	10.93 (17)	C8—C9—C10—C11	0.7 (4)
C5—C2—C3—N1	−15.1 (3)	C9—C10—C11—C6	0.4 (4)
C18—C2—C3—N1	115.0 (2)	C7—C6—C11—C10	−1.1 (3)
C1—C2—C3—N1	−127.2 (2)	C1—C6—C11—C10	174.9 (2)
C5—C2—C3—O1	102.19 (19)	O1—C1—C12—C13	−27.7 (3)
C18—C2—C3—O1	−127.7 (2)	C6—C1—C12—C13	96.7 (2)
C1—C2—C3—O1	−9.95 (15)	C2—C1—C12—C13	−128.7 (2)
C3—N1—C4—O2	160.5 (2)	O1—C1—C12—C17	154.5 (2)
C19—N1—C4—O2	2.3 (4)	C6—C1—C12—C17	−81.1 (3)
C3—N1—C4—N2	−22.0 (3)	C2—C1—C12—C17	53.5 (3)
C19—N1—C4—N2	179.8 (2)	C17—C12—C13—C14	−0.8 (4)
C5—N2—C4—O2	169.6 (2)	C1—C12—C13—C14	−178.7 (2)
C20—N2—C4—O2	3.8 (3)	C12—C13—C14—C15	0.0 (4)
C5—N2—C4—N1	−7.9 (3)	C13—C14—C15—C16	0.5 (5)
C20—N2—C4—N1	−173.7 (2)	C14—C15—C16—C17	−0.1 (5)
C4—N2—C5—O3	−157.9 (2)	C15—C16—C17—C12	−0.7 (4)
C20—N2—C5—O3	7.7 (3)	C13—C12—C17—C16	1.2 (4)
C4—N2—C5—C2	24.4 (3)	C1—C12—C17—C16	179.0 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2ⁱ	0.98	2.53	3.431 (3)	153
C7—H7···O1	0.93	2.37	2.745 (3)	104
C8—H8···O1ⁱⁱ	0.93	2.59	3.513 (3)	171
C13—H13···O1	0.93	2.41	2.752 (3)	101
C17—H17···O3	0.93	2.55	3.040 (3)	113
C20—H20B···O2	0.96	2.29	2.682 (4)	104

Symmetry codes: (i) −x+5/2, y−1/2, −z+1/2; (ii) −x+3/2, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₂₀H₂₀N₂O₃
M_r	336.38
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	298
a, b, c (Å)	8.1341 (7), 9.1004 (13), 23.485 (2)
β (°)	97.334 (2)
V (Å³)	1724.2 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.45 × 0.41 × 0.18

Data collection
Diffractometer	Bruker SMART diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.962, 0.984
No. of measured, independent and observed [I > 2σ(I)] reflections	8774, 3039, 1818
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.117, 1.01
No. of reflections	3039
No. of parameters	226
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.18

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2ⁱ	0.98	2.53	3.431 (3)	153
C7—H7···O1	0.93	2.37	2.745 (3)	104
C8—H8···O1ⁱⁱ	0.93	2.59	3.513 (3)	171
C13—H13···O1	0.93	2.41	2.752 (3)	101
C17—H17···O3	0.93	2.55	3.040 (3)	113
C20—H20B···O2	0.96	2.29	2.682 (4)	104

Symmetry codes: (i) −x+5/2, y−1/2, −z+1/2; (ii) −x+3/2, y−1/2, −z+1/2.

Acknowledgements

This work was supported by the Grants for Scientific Research of BSKY (grant No. XJ200712) from Anhui Medical University.

References

Hei, X. M., Song, Q. H., Tang, W. J., Wang, H. B. & Guo, Q. X. (2005). J. Org. Chem. 70, 2522–2527. Web of Science CrossRef PubMed CAS Google Scholar
Prakash, G., Fettinger, J. C. & Falvey, D. E. (1997). Acta Cryst. C53, 979–981. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA. Google Scholar

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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

(Z)-1,3,4a-Tri­methyl-5,5-di­phenyl-6-oxa-1,3-di­aza­bi­cyclo­[4.2.0]octane-2,4-dione

Related literature

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

(Z)-1,3,4a-Trimethyl-5,5-diphenyl-6-oxa-1,3-diazabicyclo[4.2.0]octane-2,4-dione