4,5,9,10-Tetrahydro-4-methyl-2-phenyl-9,10-epoxy-3H,10aH-cyclobuta[a]benzo[2,3,4-de]isoquinoline-3,5-dione

In the title compound, C₂₁H₁₅NO₃, which is one of the photoreaction products of N-methyl-1,8-naphthalene­dicar­box­imide with phenyl­acetyl­ene, the cyclo­butene and epoxy rings are trans to each other across the cyclo­hexene ring of the tetralin moiety. The dihedral angle between the mean planes of the cyclo­butene and cyclo­hexene rings is 112.80 (2)°, while the latter makes a dihedral angle of 103.70 (9)° with the epoxy ring. The crystal structure is stabilized by C-H...O intermolecular interactions.

S1. Comment

The photochemistry of imides with alkenes has been extensively studied (Kanaoka, 1978; Mazzocchi, 1981). However, the photochemical reactions of imides with alkynes have not been reported to date. As part of our studies of the photoinduced electron-transfer reactions of aromatic imides with various organic electron donors (Xue et al., 2000), we have investigated the photoinduced reactions of naphthalimides with alkynes. Here, we report the crystal structure of the title compound, (I), which is one of the products of the photoreaction of N-methyl-1,8-naphthalenedicarboximide with phenylacetylene. \sch

The bond lengths and angles in (I) show normal values, except for the geometry of the cyclobutene ring (Table 1). The C7—C10 bond length of 1.569 (2) Å is much longer than the typical Csp³—Csp² bond distance and is also slightly longer than that of 4-methyl-2-phenylbenzo[de]cyclobut[I]isoquinoline-3,5(2H)-dione (Liu et al., 2002) Please check this name in the light of the systematic name for (I). Such an elongation has also been observed in another cyclobutene derivative (Usman et al., 2001). This is considered to be caused by the steric effect of the bulky substituents attached at positions C7 and C10. The C9—C10 bond length of 1.572 (2) Å and the C9—C14 bond length of 1.485 (3) Å are much longer than the standard average C—C bond length (1.395 Å; Reference?) in a phenyl ring, because the C9—C14 ring is no longer aromatic.

The naphthalimide moiety has lost its coplanarity, due to the sp³ character of atoms C9, C10, C13 and C14. The C7—C10 cyclobutene ring makes a dihedral angle of 112.80 (2)° with the C9—C14 cyclohexadiene ring, while the latter makes dihedral angles of 6.47 (7) and 18.49 (8)°, respectively, with the C11/C12/C15—C18 benzo ring and the C10/C11/C18/C19/N/C20 ring. The dihedral angle between the C10/C11/C18/C19/N/C20 and C11/C12/C15—C18 rings is 15.09 (9)°. The phenyl substituent attached to the C7—C10 cyclobutene ring moiety at C7 is twisted by 150.50 (2)° with respect to the cyclobutene ring. The C13/C14/O1 epoxy ring makes a dihedral angle of 103.70 (9)° with the C9—C14 cyclohexadiene ring.

In the structure of (I), there are intermolecular C4—H4···O1 and C14—H14···O3 close contacts (Table 2).

S2. Experimental

The title compound was prepared by irradiation (with light of wavelength longer than 300 nm) of a nitrogen-purged benzene solution of N-methyl-1,8-naphthalenedicarboximide with phenylacetylene, and isolated as one of the products of the photoreaction, using flash column chromatography on silica gel (m.p. 447–448.5 K). Single crystals of (I) suitable for X-ray diffraction were obtained by recrystallization from an ethanol-ethyl acetate (Ratio?) solution.

S3. Refinement

The positions of all H atoms were fixed geometrically and C—H distances were set by the program, in the range 0.93–0.98 Å. Is this added text OK?

Computing details

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 1997); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom-numbering scheme. H atoms have been omitted for clarity.
	Fig. 2. The molecular packing diagram for the crystal of (I).

4,5,9,10-Tetrahydro-4-methyl-2-phenyl-9,10-epoxy- 3H,10aH-cyclobuta[a]benzo[2,3,4-de]isoquinoline-3,5-dione

Crystal data

C21H15NO3	F(000) = 688
Mr = 329.34	Dx = 1.350 Mg m^−3
Monoclinic, P21/c	Melting point = 447.0–448.5 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 14.801 (3) Å	Cell parameters from 25 reflections
b = 8.306 (2) Å	θ = 3.0–12.6°
c = 14.441 (2) Å	µ = 0.09 mm^−1
β = 114.15 (1)°	T = 288 K
V = 1620.0 (6) Å^3	Prism, colourless
Z = 4	0.34 × 0.30 × 0.25 mm

Data collection

Siemens P4 diffractometer	Rint = 0.011
Radiation source: normal-focus sealed tube	θmax = 25.0°, θmin = 1.5°
Graphite monochromator	h = −17→16
ω scans	k = −9→0
3306 measured reflections	l = 0→17
2852 independent reflections	3 standard reflections every 97 reflections
1870 reflections with I > 2σ(I)	intensity decay: 4.8%

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)] = 0.041	H-atom parameters constrained
wR(F^2) = 0.110	w = 1/[σ^2(Fo^2) + (0.0603P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.97	(Δ/σ)max = 0.001
2852 reflections	Δρmax = 0.19 e Å^−3
228 parameters	Δρmin = −0.12 e Å^−3
0 restraints	Extinction correction: SHELXTL (Sheldrick, 1997)
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0108 (15)

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. The structure was solved by direct methods and successive difference Fourier syntheses. 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	0.35670 (11)	0.74281 (17)	0.75866 (12)	0.0741 (5)
O2	0.09075 (11)	0.10703 (19)	0.73214 (12)	0.0820 (5)
O3	0.41892 (10)	0.21136 (18)	0.85811 (10)	0.0682 (4)
N	0.25531 (11)	0.15509 (18)	0.79497 (11)	0.0495 (4)
C1	0.18484 (14)	0.1236 (2)	0.51476 (13)	0.0520 (5)
H1	0.1461	0.1845	0.5386	0.062*
C2	0.14094 (16)	0.0065 (2)	0.44205 (15)	0.0635 (6)
H2	0.0731	−0.0110	0.4175	0.076*
C3	0.1971 (2)	−0.0838 (3)	0.40607 (16)	0.0710 (7)
H3	0.1671	−0.1613	0.3564	0.085*
C4	0.2971 (2)	−0.0601 (3)	0.44305 (17)	0.0694 (6)
H4	0.3351	−0.1230	0.4193	0.083*
C5	0.34211 (15)	0.0569 (2)	0.51554 (15)	0.0572 (5)
H5	0.4101	0.0727	0.5398	0.069*
C6	0.28605 (13)	0.1513 (2)	0.55247 (12)	0.0429 (4)
C7	0.33513 (12)	0.2805 (2)	0.62437 (13)	0.0439 (4)
C8	0.41512 (13)	0.3685 (3)	0.64237 (15)	0.0565 (5)
H8	0.4611	0.3676	0.6137	0.068*
C9	0.40689 (13)	0.4707 (2)	0.72465 (15)	0.0524 (5)
H9	0.4628	0.4566	0.7906	0.063*
C10	0.31514 (12)	0.3632 (2)	0.71184 (12)	0.0414 (4)
C11	0.21737 (12)	0.4456 (2)	0.68406 (12)	0.0410 (4)
C12	0.20140 (14)	0.6046 (2)	0.65098 (14)	0.0499 (5)
C13	0.28495 (16)	0.7059 (2)	0.65566 (16)	0.0620 (6)
H13	0.2694	0.7930	0.6058	0.074*
C14	0.38572 (15)	0.6423 (3)	0.69479 (16)	0.0610 (6)
H14	0.4297	0.6928	0.6677	0.073*
C15	0.10765 (16)	0.6708 (3)	0.62188 (15)	0.0669 (6)
H15	0.0967	0.7769	0.5994	0.080*
C16	0.03092 (16)	0.5828 (3)	0.62561 (17)	0.0730 (7)
H16	−0.0316	0.6287	0.6046	0.088*
C17	0.04622 (14)	0.4272 (3)	0.66034 (16)	0.0626 (6)
H17	−0.0056	0.3678	0.6637	0.075*
C18	0.13970 (12)	0.3585 (2)	0.69047 (13)	0.0455 (5)
C19	0.15751 (14)	0.1975 (2)	0.73739 (15)	0.0530 (5)
C20	0.33582 (14)	0.2413 (2)	0.79644 (13)	0.0465 (5)
C21	0.27420 (18)	0.0144 (3)	0.86272 (17)	0.0745 (7)
H21A	0.2496	0.0357	0.9136	0.089*
H21B	0.3441	−0.0058	0.8949	0.089*
H21C	0.2412	−0.0782	0.8238	0.089*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0886 (11)	0.0617 (9)	0.0829 (11)	−0.0223 (8)	0.0462 (9)	−0.0217 (8)
O2	0.0780 (10)	0.0791 (11)	0.0971 (12)	−0.0341 (9)	0.0441 (9)	−0.0027 (9)
O3	0.0545 (8)	0.0909 (11)	0.0569 (9)	0.0177 (8)	0.0204 (7)	0.0148 (8)
N	0.0630 (10)	0.0419 (9)	0.0497 (9)	−0.0040 (8)	0.0292 (8)	0.0013 (7)
C1	0.0569 (12)	0.0506 (12)	0.0452 (11)	0.0032 (10)	0.0177 (9)	−0.0040 (9)
C2	0.0735 (14)	0.0588 (13)	0.0470 (12)	−0.0068 (11)	0.0134 (11)	−0.0049 (11)
C3	0.108 (2)	0.0537 (13)	0.0452 (12)	−0.0020 (14)	0.0256 (13)	−0.0066 (10)
C4	0.110 (2)	0.0563 (14)	0.0580 (14)	0.0115 (13)	0.0505 (14)	−0.0040 (11)
C5	0.0717 (13)	0.0584 (12)	0.0506 (12)	0.0091 (11)	0.0344 (10)	0.0022 (10)
C6	0.0535 (11)	0.0442 (11)	0.0335 (9)	0.0053 (9)	0.0203 (8)	0.0037 (8)
C7	0.0419 (10)	0.0507 (11)	0.0421 (10)	0.0034 (9)	0.0204 (8)	0.0007 (9)
C8	0.0469 (11)	0.0725 (14)	0.0598 (12)	−0.0047 (10)	0.0318 (10)	−0.0076 (11)
C9	0.0406 (10)	0.0641 (13)	0.0538 (12)	−0.0125 (9)	0.0204 (9)	−0.0079 (10)
C10	0.0381 (9)	0.0486 (11)	0.0390 (10)	−0.0046 (8)	0.0173 (8)	−0.0033 (8)
C11	0.0422 (10)	0.0460 (11)	0.0369 (9)	−0.0040 (8)	0.0183 (8)	−0.0059 (8)
C12	0.0584 (12)	0.0511 (12)	0.0446 (11)	0.0028 (10)	0.0255 (9)	0.0034 (9)
C13	0.0840 (15)	0.0507 (13)	0.0619 (13)	−0.0062 (11)	0.0405 (12)	0.0049 (10)
C14	0.0695 (14)	0.0583 (13)	0.0685 (13)	−0.0218 (11)	0.0418 (11)	−0.0114 (11)
C15	0.0751 (15)	0.0677 (14)	0.0624 (13)	0.0233 (12)	0.0328 (12)	0.0183 (11)
C16	0.0528 (13)	0.0994 (19)	0.0667 (15)	0.0257 (13)	0.0244 (11)	0.0164 (14)
C17	0.0423 (11)	0.0914 (17)	0.0576 (13)	−0.0033 (11)	0.0240 (10)	−0.0018 (12)
C18	0.0432 (10)	0.0547 (12)	0.0422 (10)	−0.0045 (9)	0.0212 (8)	−0.0055 (9)
C19	0.0567 (12)	0.0564 (13)	0.0553 (12)	−0.0148 (11)	0.0326 (10)	−0.0106 (10)
C20	0.0491 (11)	0.0509 (11)	0.0421 (10)	0.0044 (9)	0.0214 (9)	−0.0060 (9)
C21	0.1095 (18)	0.0518 (13)	0.0729 (15)	0.0046 (12)	0.0481 (14)	0.0109 (11)

Geometric parameters (Å, º)

O1—C14	1.434 (2)	C9—C14	1.485 (3)
O1—C13	1.464 (2)	C9—C10	1.572 (2)
O2—C19	1.219 (2)	C9—H9	0.9800
O3—C20	1.213 (2)	C10—C11	1.500 (2)
N—C20	1.383 (2)	C10—C20	1.518 (3)
N—C19	1.388 (2)	C11—C12	1.391 (3)
N—C21	1.475 (2)	C11—C18	1.393 (2)
C1—C2	1.383 (3)	C12—C15	1.388 (2)
C1—C6	1.388 (2)	C12—C13	1.474 (3)
C1—H1	0.9300	C13—C14	1.460 (3)
C2—C3	1.370 (3)	C13—H13	0.9800
C2—H2	0.9300	C14—H14	0.9800
C3—C4	1.367 (3)	C15—C16	1.370 (3)
C3—H3	0.9300	C15—H15	0.9300
C4—C5	1.383 (3)	C16—C17	1.372 (3)
C4—H4	0.9300	C16—H16	0.9300
C5—C6	1.397 (2)	C17—C18	1.391 (2)
C5—H5	0.9300	C17—H17	0.9300
C6—C7	1.463 (2)	C18—C19	1.474 (3)
C7—C8	1.324 (2)	C21—H21A	0.9600
C7—C10	1.569 (2)	C21—H21B	0.9600
C8—C9	1.505 (3)	C21—H21C	0.9600
C8—H8	0.9300
C14—O1—C13	60.52 (13)	C12—C11—C10	122.36 (16)
C20—N—C19	123.96 (16)	C18—C11—C10	118.50 (16)
C20—N—C21	118.14 (17)	C15—C12—C11	119.21 (18)
C19—N—C21	117.81 (16)	C15—C12—C13	120.28 (19)
C2—C1—C6	120.71 (18)	C11—C12—C13	120.28 (17)
C2—C1—H1	119.6	C14—C13—O1	58.73 (13)
C6—C1—H1	119.6	C14—C13—C12	121.10 (18)
C3—C2—C1	120.3 (2)	O1—C13—C12	114.37 (16)
C3—C2—H2	119.9	C14—C13—H13	116.6
C1—C2—H2	119.9	O1—C13—H13	116.6
C4—C3—C2	120.0 (2)	C12—C13—H13	116.6
C4—C3—H3	120.0	O1—C14—C13	60.74 (13)
C2—C3—H3	120.0	O1—C14—C9	117.07 (17)
C3—C4—C5	120.4 (2)	C13—C14—C9	121.33 (17)
C3—C4—H4	119.8	O1—C14—H14	115.5
C5—C4—H4	119.8	C13—C14—H14	115.5
C4—C5—C6	120.4 (2)	C9—C14—H14	115.5
C4—C5—H5	119.8	C16—C15—C12	121.3 (2)
C6—C5—H5	119.8	C16—C15—H15	119.4
C1—C6—C5	118.15 (17)	C12—C15—H15	119.4
C1—C6—C7	122.88 (16)	C15—C16—C17	120.1 (2)
C5—C6—C7	118.87 (16)	C15—C16—H16	120.0
C8—C7—C6	133.57 (16)	C17—C16—H16	120.0
C8—C7—C10	92.76 (14)	C16—C17—C18	119.67 (19)
C6—C7—C10	133.64 (15)	C16—C17—H17	120.2
C7—C8—C9	96.42 (15)	C18—C17—H17	120.2
C7—C8—H8	131.8	C17—C18—C11	120.56 (18)
C9—C8—H8	131.8	C17—C18—C19	118.93 (17)
C14—C9—C8	112.80 (17)	C11—C18—C19	120.31 (16)
C14—C9—C10	116.21 (16)	O2—C19—N	120.07 (19)
C8—C9—C10	86.09 (13)	O2—C19—C18	122.89 (19)
C14—C9—H9	113.0	N—C19—C18	116.91 (16)
C8—C9—H9	113.0	O3—C20—N	120.90 (18)
C10—C9—H9	113.0	O3—C20—C10	122.52 (17)
C11—C10—C20	112.00 (14)	N—C20—C10	116.37 (15)
C11—C10—C7	117.64 (13)	N—C21—H21A	109.5
C20—C10—C7	108.29 (14)	N—C21—H21B	109.5
C11—C10—C9	117.68 (15)	H21A—C21—H21B	109.5
C20—C10—C9	113.83 (14)	N—C21—H21C	109.5
C7—C10—C9	84.55 (12)	H21A—C21—H21C	109.5
C12—C11—C18	119.14 (17)	H21B—C21—H21C	109.5
C6—C1—C2—C3	−0.1 (3)	C11—C12—C13—C14	0.0 (3)
C1—C2—C3—C4	1.0 (3)	C15—C12—C13—O1	107.5 (2)
C2—C3—C4—C5	−1.2 (3)	C11—C12—C13—O1	−66.9 (2)
C3—C4—C5—C6	0.5 (3)	C13—O1—C14—C9	−112.5 (2)
C2—C1—C6—C5	−0.5 (3)	C12—C13—C14—O1	−101.39 (19)
C2—C1—C6—C7	175.89 (17)	O1—C13—C14—C9	105.6 (2)
C4—C5—C6—C1	0.3 (3)	C12—C13—C14—C9	4.2 (3)
C4—C5—C6—C7	−176.23 (17)	C8—C9—C14—O1	167.69 (16)
C1—C6—C7—C8	−150.5 (2)	C10—C9—C14—O1	70.5 (2)
C5—C6—C7—C8	25.9 (3)	C8—C9—C14—C13	97.0 (2)
C1—C6—C7—C10	32.0 (3)	C10—C9—C14—C13	−0.1 (3)
C5—C6—C7—C10	−151.62 (18)	C11—C12—C15—C16	0.3 (3)
C6—C7—C8—C9	178.42 (19)	C13—C12—C15—C16	−174.13 (19)
C10—C7—C8—C9	−3.40 (16)	C12—C15—C16—C17	1.2 (3)
C7—C8—C9—C14	−113.44 (18)	C15—C16—C17—C18	−0.8 (3)
C7—C8—C9—C10	3.40 (16)	C16—C17—C18—C11	−1.1 (3)
C8—C7—C10—C11	121.73 (17)	C16—C17—C18—C19	173.75 (19)
C6—C7—C10—C11	−60.1 (3)	C12—C11—C18—C17	2.6 (3)
C8—C7—C10—C20	−110.07 (16)	C10—C11—C18—C17	−176.55 (15)
C6—C7—C10—C20	68.1 (2)	C12—C11—C18—C19	−172.16 (16)
C8—C7—C10—C9	3.25 (15)	C10—C11—C18—C19	8.7 (2)
C6—C7—C10—C9	−178.57 (19)	C20—N—C19—O2	172.63 (17)
C14—C9—C10—C11	−7.8 (2)	C21—N—C19—O2	−10.8 (3)
C8—C9—C10—C11	−121.30 (15)	C20—N—C19—C18	−11.5 (2)
C14—C9—C10—C20	−141.72 (17)	C21—N—C19—C18	165.13 (16)
C8—C9—C10—C20	104.74 (16)	C17—C18—C19—O2	16.0 (3)
C14—C9—C10—C7	110.68 (17)	C11—C18—C19—O2	−169.19 (17)
C8—C9—C10—C7	−2.86 (13)	C17—C18—C19—N	−159.79 (17)
C20—C10—C11—C12	147.24 (17)	C11—C18—C19—N	15.0 (2)
C7—C10—C11—C12	−86.4 (2)	C19—N—C20—O3	169.97 (17)
C9—C10—C11—C12	12.5 (2)	C21—N—C20—O3	−6.6 (3)
C20—C10—C11—C18	−33.7 (2)	C19—N—C20—C10	−15.2 (2)
C7—C10—C11—C18	92.75 (19)	C21—N—C20—C10	168.17 (15)
C9—C10—C11—C18	−168.41 (15)	C11—C10—C20—O3	−148.46 (17)
C18—C11—C12—C15	−2.2 (3)	C7—C10—C20—O3	80.2 (2)
C10—C11—C12—C15	176.91 (16)	C9—C10—C20—O3	−11.9 (2)
C18—C11—C12—C13	172.26 (16)	C11—C10—C20—N	36.8 (2)
C10—C11—C12—C13	−8.6 (3)	C7—C10—C20—N	−94.50 (17)
C14—O1—C13—C12	112.8 (2)	C9—C10—C20—N	173.40 (14)
C15—C12—C13—C14	174.41 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O1^i	0.93	2.66	3.478 (2)	147
C14—H14···O3^ii	0.98	2.42	3.329 (2)	154

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