1,4,4-Trimethyl-9-phenyl-8-oxa-9-azabicyclo [3.2.2] non-6-en-2-one

Article abstract of DOI:10.1107/S0108270100002729

The structure of the adduct of eucarvone with nitrosobenzene, C₁₆H₁₉NO₂, is reported. The [3.2.2] bicyclic system corresponds to two seven-membered rings in boat and distorted chair conformations and a six-membered ring that adopts a distorted boat conformation. No conjugation is observed between the phenyl group and the N-O system. The packing is directed mainly by a C···O hydrogen bond, C-H···O-(1-x, -y, z) and by intermolecular C-H···π interactions.

Full text of DOI:10.1107/S0108270100002729

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
parameters (Cremer & Pople, 1975)ꢁ for this riꢁng are q2 =
Ê
Ê
0.624 A, q3 = 0.070 A, '2 = 108.67 , ꢁ2 = 83.6 and QT
=
Ê
0.628 A. The conformations that the two seven-membered
rings adopt are different from those of other similar
compounds previously reported (Tinant & Declercq, 1991a).
The ring with the C6ÐC7 double bond has a distorted chair
conformation and the ring containing the NÐO bond is a
slightly distorted boat, as evidenced by the puckering para-
ISSN 0108-2701
1,4,4-Trimethyl-9-phenyl-8-oxa-9-aza-
bicyclo[3.2.2]non-6-en-2-one
Ê
Ê
meters q2 = 0.668 and 1.189 A, q3 = 0.596 and 0.082 A, '2 =
163.59 and 316.1ꢁ, '3 = 229.11 and 287.78ꢁ, QT = 0.895 and
Silvia Russi,a Helena Pardo,a Horacio Heinzen,b Eduardo
Ê
1.191 A, respectively, for the two rings. These different
b
b
a
Â
Dias, Patrick Moyna, Raul A. Mariezcurrena, Leopoldo
conformations can be explained by the presence of methyl-
group substituents which could introduce steric effects. There
is no conjugation between the phenyl group and the N9ÐO8
bond as can be deduced from the NÐO bond length
a
Âa
Suescun and Alvaro W. Mombru *
a
Â
Â
Â
Â
Laboratorio de Cristalografõa y Quõmica del Estado Solido, Facultad de Quõmica,
Â
Universidad de la Republica, Av. Gral Flores 2124, Casilla de Correos 1157,
b
Ê
Â
Â
Montevideo, Uruguay, and Catedra de Farmacognosia, Facultad de Quõmica,
[1.446 (2) A], which is longer than in other similar compounds
(Tinant & Declercq, 1991b). The distance of atom O8 from the
Â
Universidad de la Republica, Av. Gral Flores 2124, Casilla de Correos 1157,
Montevideo, Uruguay
Ê
phenyl group plane [0.299 (1) A] con®rms this conclusion.
Correspondence e-mail: amombru@bilbo.edu.uy
Received 3 September 1999
Accepted 18 February 2000
The structure of the adduct of eucarvone with nitrosobenzene,
C16H19NO2, is reported. The [3.2.2] bicyclic system corre-
sponds to two seven-membered rings in boat and distorted
chair conformations and a six-membered ring that adopts a
distorted boat conformation. No conjugation is observed
between the phenyl group and the NÐO system. The packing
is directed mainly by a CÁ Á ÁO hydrogen bond, CÐHÁ Á ÁO-
(1 x, y, z) and by intermolecular CÐHÁ Á Áꢀ interactions.
Comment
Diels±Alder reactions using NO compounds as dieno®les
constitute a ¯exible key for natural products synthesis, espe-
cially for alkaloids such as lycorine. Reactions between nitroso
compounds and dienes are strongly dependent on stereo-
electronic factors which direct the regiochemistry of the
cycloaddition reaction. Although the orientation of the
cycloaddition can be determined by spectroscopic methods,
crystal-structure determination of the ®nal product of the
reaction is necessary for a complete analysis of the confor-
mation of the molecule. This communication reports the
structure of the adduct of the eucarvone (a rearranged
monoterpene derived from carvone, possessing a diene
system) with nitrosobenzene, (I) (Hart et al., 1979), as part of
the research into the synthesis of amarylideaceas alkaloids.
Figure 1
ZORTEP (Zsolnai & Pritzkow, 1995) drawing of the molecular structure
of (I) showing 30% probability displacement ellipsoids.
The packing is directed mainly by intermolecular contacts
involving the H atoms bonded to C6 and C7. C7ÐH7Á Á ÁO21-
(1
x, y, z) appears to be a hydrogen bond where the
distances C7ÐH7, H7Á Á ÁO21 and C7Á Á ÁO21 are 0.92 (2),
ꢁ
Ê
2.50 (2) and 3.326 (2) A [the angle C7ÐH7Á Á ÁO21 is 150 (2) ],
respectively. C6ÐH6 interacts with the phenyl group of a
neighboring molecule at ( x, y, z) with the characteristic
distances (H6Á Á Áring centroid, C6Á Á Áring centroid and
Ê
H6Á Á Áring mean plane) of 2.749, 3.665 and 2.725 A, respec-
tively; the C6ÐH6Á Á Áring centroid angle is 153.64ꢁ.
The structure has also been used to determine the regio-
chemistry of the cycloaddition reaction. The O atom of the
dienophile adds to C1, ꢂ to the carbonyl exclusively, yielding
only one adduct. The stereoelectronic structure of the adduct
also accounts for some of the signals detected in the 1H NMR
spectrum. The most relevant are the deshielding of the proton
bonded to C5 by an anisotropic effect due to the orientation of
the phenyl group, and the nonequivalent, diastereotopic
protons, belonging to C3, where the proton lying equatorial is
shielded by the carbonyl group.
The title compound contains a [3.2.2] bicyclic system with
the endocyclic torsion angles listed in Table 1. The six-
membered ring shows a distorted boat conformation as could
be predicted by the presence of the bridge. The puckering
ꢀ
672 # 2000 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2000). C56, 672±673

organic compounds
Table 1
Selected geometric parameters (A, ).
Experimental
ꢁ
Ê
Eucarvone (Corey & Burke, 1956) (0.1 g, 0.67 mmol) and nitroso-
benzene (0.071 g, 0.67 mmol) were dissolved in dichloromethane
(30 ml). After stirring in the darkness for 10 h, the green colour
disappeared. The solvent was distilled at reduced pressure and the oil
was dissolved in pentane. Leaving the solution overnight at 261 K
yielded colourless crystals suitable for X-ray diffraction (m.p. 329±
331 K). MS (Shimadzu GC±MS QP 1100 EX, id, 20 eV): m/z = 257
(M+, 89.7%); 214 (37%); 174 (64.5%); 172 (43.6%); 130 (89.4%); 107
(PhNO+, 100%); 95 (72.7%); 77 (Ph+, 89.3%). 1H NMR (CDCl3,
400 MHz, Bruker Avance DPX400, ꢃ p.p.m.): 7.28 (dd, 2H, J = 8.6,
7.3 Hz, H03, H05); 7.04 (dd, 2H, J = 8.6, 1.0 Hz, H02, H06); 6.99 (tt, 1H,
J = 7.3 Â 2, 1.0 Â 2 Hz, H04); 6.17 (dd, 1H, J = 9.1, 7.3 Hz, H6); 6.07
(d, 1H, J = 9.1 Hz, H7); 4.02 (d, 1H, J = 7.3 Hz, H5); 3.46 (d, 1H, J =
13.4 Hz, H3); 2.32 (d, 1H, J = 13.4 Hz, H3 gem); 1.67 (s, 3H, CH3
bridge); 1.47, 1.11 (s, 3H each, CH3 gem). 13C NMR (CDCl3, p.p.m.,
400 MHz): 206.4 (C2); 152.7 (C01); 132.6 (C6); 129.0 (C7); 128.5 Â 2
(C03, C05); 122.1 (C04); 117.3 Â 2 (C02, C06); 82.6 (C1); 71.4 (C5); 53.7
(C3); 35.6 (C4); 29.6, 26.2 (CH3 gem); 19.9 (CH3 bridge).
O8ÐN9
O8ÐC1
N9ÐC5
C5ÐC6
C5ÐC4
1.4461 (17)
1.4669 (19)
1.486 (2)
1.496 (2)
1.547 (2)
C6ÐC7
C3ÐC2
C3ÐC4
C2ÐC1
C1ÐC7
1.313 (3)
1.497 (3)
1.548 (2)
1.535 (3)
1.501 (3)
N9ÐO8ÐC1
O8ÐN9ÐC5
N9ÐC5ÐC6
N9ÐC5ÐC4
C6ÐC5ÐC4
C2ÐC3ÐC4
117.69 (11)
111.19 (11)
109.20 (13)
111.23 (13)
115.28 (13)
116.65 (15)
C5ÐC4ÐC3
C3ÐC2ÐC1
O8ÐC1ÐC7
O8ÐC1ÐC2
C7ÐC1ÐC2
C6ÐC7ÐC1
112.31 (14)
117.15 (14)
111.57 (13)
106.88 (13)
105.79 (14)
117.48 (17)
C1ÐO8ÐN9ÐC5
O8ÐN9ÐC5ÐC6
O8ÐN9ÐC5ÐC4
N9ÐC5ÐC6ÐC7
C4ÐC5ÐC6ÐC7
N9ÐC5ÐC4ÐC3
C6ÐC5ÐC4ÐC3
C2ÐC3ÐC4ÐC5
16.70 (18)
55.29 (16)
73.06 (16)
46.37 (19)
79.7 (2)
50.25 (19)
74.76 (19)
40.3 (2)
C4ÐC3ÐC2ÐC1
N9ÐO8ÐC1ÐC7
N9ÐO8ÐC1ÐC2
C3ÐC2ÐC1ÐO8
C3ÐC2ÐC1ÐC7
C5ÐC6ÐC7ÐC1
O8ÐC1ÐC7ÐC6
C2ÐC1ÐC7ÐC6
53.0 (2)
31.29 (19)
83.91 (15)
29.4 (2)
89.66 (19)
3.5 (2)
43.1 (2)
72.72 (19)
Crystal data
3
C16H19NO2
Mr = 257.32
Dx = 1.205 Mg m
Mo Kꢂ radiation
Cell parameters from 25
re¯ections
Monoclinic, P21=n
Ê
a = 10.417 (3) A
SHELXL97 (Sheldrick, 1997); molecular graphics: ZORTEP
(Zsolnai & Pritzkow, 1995); software used to prepare material for
publication: PLATON98 (Spek, 1998) and CSD (Allen & Kennard,
1993).
ꢁ = 20.17±25.40ꢁ
ꢅ = 0.079 mm
T = 293 (2) K
Ê
b = 8.263 (2) A
1
Ê
c = 16.5049 (12) A
ꢄ = 92.746 (11)ꢁ
3
Ê
V = 1419.0 (5) A
Z = 4
Prismatic, colourless
0.20 Â 0.17 Â 0.13 mm
This research was supported by CONICYT (Consejo
Data collection
Â
Nacional de Investigacõon Cientõ®ca y Tecnologica, Uruguay)
and CSIC (Comision Sectorial de Investigacion Cientõ®ca,
Â
Â
Rigaku AFC-7S diffractometer
ꢁ/2ꢁ scans
Absorption correction: scan
(Molecular Structure Corpora-
tion, 1993)
Tmin = 0.964, Tmax = 1.000
3571 measured re¯ections
3254 independent re¯ections
1819 re¯ections with I > 2ꢆ(I)
Rint = 0.017
max = 27.49ꢁ
Â
Â
Â
ꢁ
Â
Universidad de la Republica), Project 195. We thank the
h = 7 ! 13
k = 8 ! 10
Spanish Research Council (CSIC) for providing us with a free-
of-charge license to the CSD system.
l = 21 ! 21
3 standard re¯ections
every 150 re¯ections
intensity decay: none
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SX1097). Services for accessing these data are
described at the back of the journal.
Re®nement
Re®nement on F2
R[F2 > 2ꢆ(F2)] = 0.042
wR(F2) = 0.139
S = 1.027
3254 re¯ections
230 parameters
H atoms treated by a mixture of
independent and constrained
re®nement
w = 1/[ꢆ2(Fo2) + (0.0692P)2
+ 0.0281P]
where P = (Fo2 + 2Fc2)/3
(Á/ꢆ)max < 0.001
References
Allen, F. H. & Kennard, O. (1993). Chem. Des. Autom. News, 8, 31±37.
Corey, E. J. & Burke, H. J. (1956). J. Am. Chem. Soc. 78, 174±180.
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354±1358.
Hart, H., Ramaswami, S. K. & Willer, R. (1979). J. Org. Chem. 44, 1±6.
Molecular Structure Corporation (1993). MSC/AFC Diffractometer Control
Software. MSC, 3200 Research Forest Drive, The Woodlands, TX 77381,
USA.
3
Ê
Áꢇmax = 0.15 e A
3
Ê
0.18 e A
Áꢇmin
=
Sheldrick, G. M. (1990). Acta Cryst. A46, 467±473.
Sheldrick, G. M. (1997). SHELXL97. University of Gottingen, Germany.
È
Data collection: MSC/AFC Diffractometer Control Software
(Molecular Structure Corporation, 1993); cell re®nement: MSC/AFC
Diffractometer Control Software; data reduction: MSC/AFC
Diffractometer Control Software; program(s) used to solve structure:
SHELXS97 (Sheldrick, 1990); program(s) used to re®ne structure:
Spek, A. L. (1998). PLATON98. University of Utrecht, The Netherlands.
Tinant, B. & Declercq, J.-P. (1991a). Acta Cryst. C47, 1266±1269.
Tinant, B. & Declercq, J.-P. (1991b). Acta Cryst. C47, 827±829.
Zsolnai, L. & Pritzkow, H. (1995). ZORTEP. University of Heidelberg,
Germany.
ꢀ
Acta Cryst. (2000). C56, 672±673
Silvia Russi et al. C16H19NO2 673