2,9-Bis(3-nitrophenyl)-1-azaadamantan-4-one

The title compound, 2,9-bis(3-nitro­phenyl)-1-aza­tri­cyclo[3.3.1.1^3,7]­decan-4-one, C₂₁H₁₉N₃O₅, has a tricyclic structure. The torsion angles may be used to describe the relationship of the carbonyl group to the adjacent faces, whereby it is seen that the angles on the face of the aryl­piperidinone side [122.0 (3) and -122.0 (3)°] are greater than those on the cyclo­hexanone side [-119.8 (4) and 119.9 (4)°]. Although these differences may explain a facial selectivity during nucleophilic addition to the carbonyl group, the presence of the aryl rings is probably also important.

S1. Comment

Numerous investigations have shown that substitution in adamantanones and azaadamantanones may affect facial selectivity during nucleophilic addition to the carbonyl group (Kaselj et al., 1999). Structural studies of azaadamantanone have been used to explain its facial selectivity; the distortion in the calculated geometry (HF/6–31G*) of azaadamantanone has been discussed by Gung & Wolf (1996). We recently designed the 2-eq-9-ax-diarylazaadamantan-4-ones analogues to the title compound, (I), as probes for facial selectivity in the nucleophilic addition of sodium borohydride in methanol. The highly preferential anti attack in the reduction of these ketones has been described; both steric and electronic effects were involved (Jiménez-Cruz et al., 2000). \sch

The molecular structure of (I) is shown in Fig. 1 and selected geometric parameters are given in Table 1. The molecule consists of a tricyclic azaadamantanone cage with aryl rings (3-nitrophenyl) substituted at the 3 and 9 positions. Rings A (C11 to C16) and B (C17 to C22) are attached to atoms C2 and C9 in equatorial and axial positions, respectively, relative to the piperidinone ring. The rotation between each aryl ring and the tricyclic framework may be described by the torsion angles C3—C2—C11—C12 [-28.4 (4)°, ring A] and C5—C9—C17—C18 [-37.2 (4)°, ring B]. The aromatic rings are themselves planar [mean deviations 0.006 (2) Å for ring A and 0.008 (3) Å for ring B], and although the ring and the nitro group in pure m-nitroacetophenone are almost planar, with an angle between the groups of 1.8 (2)° (Feeder et al., 1996), in (I) the planes of the 3-nitrophenyl groups are rotated significantly away from the planes of the rings [11.2 (6)° for ring A and 10.7 (2)° for B].

The average C—C bond length within the adamantane cage in (I) is 1.53 (4) Å. The bonds N1—C2, N1—C9 and N1—C8 are 1.479 (4), 1.484 (4) and 1.472 (4) Å, respectively. These values are greater than those reported for 2-phenyl-3,5,7-trimethylazaadamantan-4,10-dione, (II) (Risch et al., 1991), in which the N—C distances are 1.462 (3), 1.458 (3) and 1.452 (3) Å, and are less than those described in chlorophenyloxyazaadamantane hydrochloride, (III) (Fernández et al., 1989), in which the N—C distances are 1.514 (7), 1.49 (3) and 1.50 (3) Å. The C═O distance (C4—O1) is 1.214 (4) Å in (I), which is similar to the values described in (II) (1.211 and 1.214 Å). The C3—C4—C5 bond angle is 112.7 (3)° in (I), which is less than the values reported in (II) (114.25 and 114.95°; Risch et al., 1991).

The torsion angles used to describe the two faces of the other side of the cage (see Scheme) show that the angles on the arylpiperidinone side [C9—C5—C4—O1 122.0 (3)° and C2—C3—C4—O1 - 122.0 (3)°] are greater than on the cyclohexanone side [C6—C5—C4—O1 - 119.8 (4)° and C10—C3—C4—O1 119.9 (4)°]. These geometrical parameters may provide some understanding of the nucleophilic addition reactions on these substrates. Although these differences imply a facial asymmetry that may explain a preferential selectivity, the presence of the aryl rings is also important in preferential attack on the cyclohexanone face.

The molecules in the crystal of (I) are linked by several weak C—H···O bonds involving the O atoms in the carbonyl ketone and the nitro groups (Table 2).

S2. Experimental

The title compound was prepared by the procedure described by Jiménez-Cruz et al. (2000). After purification via a chromatographic column, crystals of (I) were grown by slow evaporation of a chloroform-hexane solution at room temperature (m.p. 498–500 K).

S3. Refinement

The positional parameters of the H atoms were calculated geometrically and fixed, with U_iso(H) = 1.2U_eq of the parent atom.

Computing details

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick 1990); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. The molecular view of (I) with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

2,9-Bis(3-nitrophenyl)-1-azatricyclo[3.3.1.1^3,7]decan-4-one

Crystal data

C21H19N3O5	F(000) = 1648
Mr = 393.39	Dx = 1.435 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 40 reflections
a = 13.318 (1) Å	θ = 3.0–12.5°
b = 15.217 (2) Å	µ = 0.10 mm^−1
c = 17.965 (1) Å	T = 293 K
V = 3640.8 (6) Å^3	Block, yellow
Z = 8	0.6 × 0.3 × 0.3 mm

Data collection

Siemens P4/PC diffractometer	Rint = 0.049
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.3°
Graphite monochromator	h = −1→15
θ/2θ scans	k = −1→18
3999 measured reflections	l = −1→21
3185 independent reflections	3 standard reflections every 97 reflections
1685 reflections with I > 2σ(I)	intensity decay: <2%

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)] = 0.058	H-atom parameters constrained
wR(F^2) = 0.133	w = 1/[σ^2(Fo^2) + (0.0478P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.002
3185 reflections	Δρmax = 0.35 e Å^−3
263 parameters	Δρmin = −0.26 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: 0.0012 (4)

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
O1	0.06435 (16)	0.01712 (16)	0.29009 (15)	0.0573 (7)
N1	0.26213 (17)	0.18754 (15)	0.37493 (15)	0.0369 (6)
C2	0.2796 (2)	0.0916 (2)	0.37123 (17)	0.0360 (7)
H2	0.2406	0.0657	0.4104	0.043*
C3	0.2401 (2)	0.0531 (2)	0.29678 (18)	0.0394 (7)
H3	0.2512	−0.0092	0.2946	0.047*
C4	0.1286 (2)	0.0734 (2)	0.29550 (18)	0.0402 (7)
C5	0.1069 (2)	0.1705 (2)	0.29975 (18)	0.0441 (8)
H5	0.0358	0.1805	0.2990	0.053*
C6	0.1575 (3)	0.2161 (2)	0.2342 (2)	0.0537 (9)
H6A	0.1449	0.2782	0.2365	0.064*
H6B	0.1305	0.1943	0.1882	0.064*
C7	0.2714 (3)	0.1985 (2)	0.2370 (2)	0.0486 (8)
H7	0.3045	0.2287	0.1970	0.058*
C8	0.3107 (2)	0.2319 (2)	0.31167 (19)	0.0484 (8)
H8A	0.3816	0.2210	0.3144	0.058*
H8B	0.3003	0.2942	0.3155	0.058*
C9	0.1527 (2)	0.2056 (2)	0.37316 (19)	0.0417 (8)
H9	0.1456	0.2684	0.3723	0.050*
C10	0.2904 (2)	0.0993 (2)	0.23125 (18)	0.0460 (8)
H10A	0.2639	0.0770	0.1853	0.055*
H10B	0.3613	0.0882	0.2322	0.055*
C11	0.3900 (2)	0.0710 (2)	0.38790 (17)	0.0363 (7)
C12	0.4348 (2)	−0.0043 (2)	0.36070 (18)	0.0393 (7)
H12	0.3986	−0.0443	0.3293	0.047*
C13	0.5348 (2)	−0.0209 (2)	0.38024 (19)	0.0405 (7)
C14	0.5897 (2)	0.0326 (2)	0.4250 (2)	0.0465 (8)
H14	0.6584	0.0188	0.4363	0.056*
C15	0.5444 (2)	0.1065 (2)	0.4531 (2)	0.0500 (9)
H15	0.5814	0.1450	0.4854	0.060*
C16	0.4449 (2)	0.1258 (2)	0.43474 (19)	0.0450 (8)
H16	0.4143	0.1783	0.4538	0.054*
N2	0.5801 (2)	−0.1012 (2)	0.3506 (2)	0.0593 (9)
O2	0.52849 (19)	−0.15533 (17)	0.3193 (2)	0.0818 (10)
O3	0.6713 (2)	−0.1085 (2)	0.3576 (3)	0.1181 (16)
C17	0.1001 (2)	0.1736 (2)	0.44326 (18)	0.0399 (7)
C18	−0.0040 (2)	0.1635 (2)	0.4443 (2)	0.0443 (8)
H18	−0.0426	0.1750	0.4002	0.053*
C19	−0.0497 (2)	0.1349 (2)	0.50858 (19)	0.0446 (8)
C20	−0.0004 (3)	0.1170 (2)	0.5736 (2)	0.0542 (9)
H20	−0.0353	0.0967	0.6171	0.065*
C21	0.1035 (3)	0.1288 (3)	0.5729 (2)	0.0610 (10)
H21	0.1420	0.1172	0.6170	0.073*
C22	0.1515 (2)	0.1574 (3)	0.50934 (19)	0.0504 (9)
H22	0.2228	0.1667	0.5107	0.060*
N3	−0.1605 (2)	0.1260 (2)	0.50771 (19)	0.0571 (8)
O4	−0.2022 (2)	0.0940 (2)	0.56047 (18)	0.0765 (9)
O5	−0.2055 (2)	0.1558 (3)	0.45438 (19)	0.0989 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0361 (11)	0.0630 (16)	0.0728 (16)	−0.0124 (12)	−0.0094 (12)	0.0030 (14)
N1	0.0280 (12)	0.0325 (13)	0.0502 (15)	0.0016 (10)	−0.0003 (12)	0.0017 (12)
C2	0.0261 (13)	0.0361 (15)	0.0456 (17)	0.0005 (12)	−0.0006 (13)	−0.0005 (14)
C3	0.0264 (13)	0.0362 (15)	0.0555 (18)	0.0002 (12)	−0.0015 (14)	−0.0030 (16)
C4	0.0301 (14)	0.0494 (18)	0.0410 (16)	−0.0029 (14)	−0.0027 (14)	−0.0003 (16)
C5	0.0311 (15)	0.0485 (18)	0.0526 (19)	0.0068 (14)	−0.0036 (15)	0.0052 (17)
C6	0.0508 (19)	0.054 (2)	0.057 (2)	0.0056 (18)	−0.0054 (17)	0.0140 (19)
C7	0.0462 (18)	0.0497 (19)	0.0499 (19)	−0.0032 (16)	0.0078 (16)	0.0094 (17)
C8	0.0426 (17)	0.0400 (17)	0.063 (2)	−0.0027 (15)	0.0051 (17)	0.0036 (17)
C9	0.0294 (14)	0.0379 (15)	0.058 (2)	0.0055 (13)	0.0013 (15)	0.0011 (16)
C10	0.0360 (16)	0.0560 (19)	0.0459 (18)	0.0001 (15)	0.0043 (15)	−0.0038 (16)
C11	0.0264 (13)	0.0406 (16)	0.0419 (15)	−0.0007 (13)	−0.0009 (13)	−0.0020 (14)
C12	0.0275 (13)	0.0416 (16)	0.0489 (18)	0.0003 (13)	−0.0036 (13)	−0.0036 (15)
C13	0.0287 (13)	0.0394 (16)	0.0533 (18)	0.0028 (13)	0.0011 (14)	0.0029 (16)
C14	0.0268 (14)	0.0530 (19)	0.060 (2)	−0.0022 (15)	−0.0037 (15)	0.0052 (18)
C15	0.0348 (16)	0.057 (2)	0.058 (2)	−0.0121 (16)	−0.0111 (16)	−0.0050 (18)
C16	0.0354 (15)	0.0442 (18)	0.0553 (19)	0.0021 (14)	−0.0034 (16)	−0.0089 (16)
N2	0.0356 (15)	0.0510 (17)	0.091 (2)	0.0116 (14)	−0.0063 (16)	−0.0017 (18)
O2	0.0456 (13)	0.0467 (14)	0.153 (3)	0.0021 (13)	−0.0056 (18)	−0.0261 (19)
O3	0.0469 (16)	0.105 (3)	0.202 (4)	0.0392 (17)	−0.041 (2)	−0.065 (3)
C17	0.0329 (14)	0.0359 (16)	0.0509 (19)	0.0039 (13)	−0.0001 (15)	−0.0059 (15)
C18	0.0359 (16)	0.0460 (19)	0.051 (2)	−0.0023 (15)	−0.0021 (15)	0.0003 (17)
C19	0.0352 (15)	0.0462 (18)	0.0524 (19)	−0.0056 (15)	0.0037 (15)	−0.0050 (17)
C20	0.0469 (19)	0.060 (2)	0.056 (2)	0.0072 (18)	0.0142 (18)	0.005 (2)
C21	0.0468 (19)	0.084 (3)	0.052 (2)	0.014 (2)	−0.0054 (18)	0.005 (2)
C22	0.0337 (15)	0.065 (2)	0.052 (2)	0.0043 (17)	−0.0031 (16)	−0.0065 (19)
N3	0.0373 (15)	0.074 (2)	0.0596 (19)	−0.0146 (16)	0.0029 (15)	−0.0004 (18)
O4	0.0557 (15)	0.084 (2)	0.090 (2)	−0.0156 (15)	0.0189 (16)	0.0163 (18)
O5	0.0419 (15)	0.172 (4)	0.083 (2)	−0.021 (2)	−0.0015 (15)	0.016 (2)

Geometric parameters (Å, º)

O1—C4	1.214 (4)	C12—C13	1.401 (4)
N1—C8	1.472 (4)	C13—C14	1.359 (5)
N1—C2	1.479 (4)	C13—N2	1.462 (4)
N1—C9	1.484 (4)	C14—C15	1.372 (5)
C2—C11	1.533 (4)	C15—C16	1.397 (5)
C2—C3	1.553 (4)	N2—O2	1.212 (4)
C3—C4	1.517 (4)	N2—O3	1.226 (4)
C3—C10	1.526 (4)	C17—C22	1.392 (5)
C4—C5	1.507 (5)	C17—C18	1.396 (4)
C5—C6	1.524 (5)	C18—C19	1.376 (5)
C5—C9	1.548 (4)	C19—C20	1.367 (5)
C6—C7	1.542 (5)	C19—N3	1.482 (4)
C7—C8	1.528 (5)	C20—C21	1.395 (5)
C7—C10	1.533 (5)	C21—C22	1.379 (5)
C9—C17	1.521 (4)	N3—O4	1.202 (4)
C11—C12	1.382 (4)	N3—O5	1.218 (4)
C11—C16	1.392 (4)
C8—N1—C2	110.4 (2)	C12—C11—C2	121.0 (3)
C8—N1—C9	109.3 (3)	C16—C11—C2	119.9 (3)
C2—N1—C9	109.7 (2)	C11—C12—C13	118.1 (3)
N1—C2—C11	110.1 (2)	C14—C13—C12	123.5 (3)
N1—C2—C3	111.0 (3)	C14—C13—N2	119.6 (3)
C11—C2—C3	114.6 (2)	C12—C13—N2	116.9 (3)
C4—C3—C10	108.9 (3)	C13—C14—C15	118.2 (3)
C4—C3—C2	105.5 (3)	C14—C15—C16	120.1 (3)
C10—C3—C2	110.0 (2)	C11—C16—C15	121.0 (3)
O1—C4—C5	124.1 (3)	O2—N2—O3	123.2 (3)
O1—C4—C3	123.1 (3)	O2—N2—C13	120.1 (3)
C5—C4—C3	112.7 (3)	O3—N2—C13	116.6 (3)
C4—C5—C6	108.8 (3)	C22—C17—C18	117.2 (3)
C4—C5—C9	107.8 (3)	C22—C17—C9	122.5 (3)
C6—C5—C9	109.1 (3)	C18—C17—C9	120.3 (3)
C5—C6—C7	109.3 (3)	C19—C18—C17	119.1 (3)
C8—C7—C10	109.3 (3)	C20—C19—C18	124.6 (3)
C8—C7—C6	107.9 (3)	C20—C19—N3	118.0 (3)
C10—C7—C6	109.3 (3)	C18—C19—N3	117.4 (3)
N1—C8—C7	112.0 (3)	C19—C20—C21	116.3 (4)
N1—C9—C17	112.0 (3)	C22—C21—C20	120.5 (4)
N1—C9—C5	109.9 (3)	C21—C22—C17	122.3 (3)
C17—C9—C5	114.5 (2)	O4—N3—O5	122.9 (3)
C3—C10—C7	109.3 (3)	O4—N3—C19	119.3 (3)
C12—C11—C16	119.0 (3)	O5—N3—C19	117.7 (3)
C8—N1—C2—C11	70.3 (3)	C3—C2—C11—C12	−28.4 (4)
C9—N1—C2—C11	−169.2 (2)	N1—C2—C11—C16	29.6 (4)
C8—N1—C2—C3	−57.7 (3)	C3—C2—C11—C16	155.6 (3)
C9—N1—C2—C3	62.8 (3)	C16—C11—C12—C13	−1.6 (5)
N1—C2—C3—C4	−59.9 (3)	C2—C11—C12—C13	−177.7 (3)
C11—C2—C3—C4	174.5 (3)	C11—C12—C13—C14	0.7 (5)
N1—C2—C3—C10	57.4 (3)	C11—C12—C13—N2	−180.0 (3)
C11—C2—C3—C10	−68.2 (3)	C12—C13—C14—C15	0.6 (5)
C10—C3—C4—O1	119.9 (4)	N2—C13—C14—C15	−178.7 (3)
C2—C3—C4—O1	−122.0 (3)	C13—C14—C15—C16	−0.9 (5)
C10—C3—C4—C5	−58.6 (4)	C12—C11—C16—C15	1.3 (5)
C2—C3—C4—C5	59.4 (3)	C2—C11—C16—C15	177.4 (3)
O1—C4—C5—C6	−119.8 (4)	C14—C15—C16—C11	0.0 (5)
C3—C4—C5—C6	58.8 (4)	C14—C13—N2—O2	169.8 (4)
O1—C4—C5—C9	122.0 (3)	C12—C13—N2—O2	−9.5 (5)
C3—C4—C5—C9	−59.5 (4)	C14—C13—N2—O3	−12.0 (6)
C4—C5—C6—C7	−58.7 (4)	C12—C13—N2—O3	168.6 (4)
C9—C5—C6—C7	58.7 (4)	N1—C9—C17—C22	19.9 (4)
C5—C6—C7—C8	−57.9 (4)	C5—C9—C17—C22	145.9 (3)
C5—C6—C7—C10	60.9 (4)	N1—C9—C17—C18	−163.3 (3)
C2—N1—C8—C7	59.2 (3)	C5—C9—C17—C18	−37.2 (4)
C9—N1—C8—C7	−61.5 (3)	C22—C17—C18—C19	−2.7 (5)
C10—C7—C8—N1	−58.9 (3)	C9—C17—C18—C19	−179.7 (3)
C6—C7—C8—N1	59.9 (4)	C17—C18—C19—C20	1.6 (6)
C8—N1—C9—C17	−171.2 (2)	C17—C18—C19—N3	179.3 (3)
C2—N1—C9—C17	67.6 (3)	C18—C19—C20—C21	−0.3 (6)
C8—N1—C9—C5	60.4 (3)	N3—C19—C20—C21	−178.0 (4)
C2—N1—C9—C5	−60.8 (3)	C19—C20—C21—C22	0.3 (6)
C4—C5—C9—N1	58.1 (3)	C20—C21—C22—C17	−1.5 (6)
C6—C5—C9—N1	−60.0 (3)	C18—C17—C22—C21	2.7 (5)
C4—C5—C9—C17	−69.0 (3)	C9—C17—C22—C21	179.7 (3)
C6—C5—C9—C17	172.9 (3)	C20—C19—N3—O4	−8.5 (6)
C4—C3—C10—C7	58.4 (3)	C18—C19—N3—O4	173.6 (3)
C2—C3—C10—C7	−56.8 (3)	C20—C19—N3—O5	168.0 (4)
C8—C7—C10—C3	57.2 (3)	C18—C19—N3—O5	−9.9 (6)
C6—C7—C10—C3	−60.7 (4)	C3—C2—C11—C12	−28.4 (4)
N1—C2—C11—C12	−154.3 (3)	C5—C9—C17—C18	−37.2 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O4^i	0.96	2.54	3.249 (4)	131
C20—H20···O1^i	0.96	2.44	3.300 (5)	150
C21—H21···O3^ii	0.96	2.53	3.263 (6)	133

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