Unusual synthesis of phosphorus-containing 1,3-oxazine- 2,4-dione of zwitter-ionic structure by the N-reaction of cyano-carbanion with 2,4,6-trinitrofluorobenzene

Article abstract of DOI:10.1016/j.mencom.2010.01.015

A phosphonium zwitterion containing a carbamate moiety is a cyano-carbanion, and it reacts with 2,4,6-trinitrofluorobenzene as an N-nucleophile to form substituted oxazine-2,4-dione and ethyl fluoride.

Full text of DOI:10.1016/j.mencom.2010.01.015

Mendeleev
Communications
Mendeleev Commun., 2010, 20, 39–40
Unusual synthesis of phosphorus-containing 1,3-oxazine-
2,4-dione of zwitter-ionic structure by the N-reaction
of cyano-carbanion with 2,4,6-trinitrofluorobenzene
Yuri G. Gololobov,* Victor N. Khrustalev, Nikolai V. Slepchenkov,
Alexander S. Peregudov and Mikhail Yu. Antipin
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow,
Russian Federation. Fax: +7 495 135 5085; e-mail: Yugol@ineos.ac.ru
DOI: 10.1016/j.mencom.2010.01.015
A phosphonium zwitterion containing a carbamate moiety is a cyano-carbanion, and it reacts with 2,4,6-trinitrofluorobenzene as
an N-nucleophile to form substituted oxazine-2,4-dione and ethyl fluoride.
As a rule, the nucleophilic aromatic substitution of the fluorine
atom in nitrofluorobenzenes occurs via the formation of σ-com-
plexes 1a, 11 (Scheme 1).
of fluorine in polynitrofluorobenzenes, which result in the
polyconjugated structures rather than aromatic compounds.
Here, we report a new unexpected example of cyano-carbanion
N-reactivity concerning substitution of fluorine in 2,4,6-trinitro-
fluorobenzene. P-zwitterion containing a carbamate moiety 3 was
used as a cyano-carbanion. The reaction of 3 with 2,4,6-tri-
nitrofluorobenzene led to an unusual result. Substituted oxazine-
2,4-dione 5 and ethyl fluoride were obtained. It is possible to
assume that the transformation of intermediate 4 in oxazine 5
took place according to Scheme 2. However, the scheme of a
cycle 5 formation seems to be more complex because the 19F
and 31P NMR spectral monitoring of the reaction mass shows
that, in the course of the reaction (for about two weeks), the
signals appear and disappear periodically, which may be assigned
to the intermediates that have not been identified yet. The IR,
NO2
NO2
Y
F
Y
– F –
1
2
NO2
Y–
F
+
Y
NO2
F
1a
1
UV, H and 13C NMR spectra and X-ray diffraction analysis
Scheme 1
C(18)
The transformations of σF-complexes 1 include elimination
of the fluoride ion to give new aromatic compounds 2. Previ-
ously,2–6 we described unusual cases of the nucleophilic aromatic
substitutions of fluorine atoms in polynitrofluorobenzenes. These
investigations consider the ‘nonconventional’ chemistry of σF-com-
plexes including reactions of nucleophilic aromatic substitution
C(19)
C(17)
C(16)
C(20)
C(21)
P(1)
C(15)
O(5)
C(14)
C(13)
C(22)
N(3)
O(4)
C(23)
O(9)
N(5)
N(2)
C(3)
O(3)
C(24)
O
C(4)
C(25)
C(26)
C(2)
N(1)
Pr3i PCH2C–C–N–COOEt
O2N
O(1)
O(2)
O(7)
Pr3i PCH2C=C=N
CN Ar
C(10)
C(28)
C(27)
N(4)
O(6)
C(9)
C(8)
C(5)
C(11)
NO2
C(1)
TNFB
F
O
O(8)
C(6)
C(7)
O
O2N
CH2 Me
N
Pr3i PCH2C=C=N
Ar
C
C(12)
O
O
C
NAr
Figure 1 Molecular structure of 5 (ellipsoids are drawn at 40% probability
level), all hydrogen atoms are omitted for clarity. Selected bond lengths
(Å): O(1)–C(1) 1.372(4), O(1)–C(4) 1.396(4), O(2)–C(1) 1.201(4), O(3)–
C(2) 1.215(4), N(1)–C(1) 1.360(5), N(1)–C(2) 1.424(4), N(1)–C(5) 1.469(5),
N(2)–C(4) 1.321(4), N(2)–C(23) 1.343(5), N(3)–C(24) 1.474(4), N(4)–
C(26) 1.443(5), N(5)–C(28) 1.467(4), C(2)–C(3) 1.432(4), C(3)–C(4)
1.365(5), C(3)–C(13) 1.506(4), C(23)–C(28) 1.424(4), C(23)–C(24)
1.428(4), C(24)–C(25) 1.353(5), C(25)–C(26) 1.389(5), C(26)–C(27)
1.387(5), C(27)–C(28) 1.377(5); selected bond angles (°): C(1)–O(1)–C(4)
123.3(3), C(1)–N(1)–C(2) 124.3(3), C(4)–N(2)–C(23) 125.6(3), N(1)–
C(1)–O(1) 116.7(3), N(1)–C(2)–C(3) 115.6(3), C(4)–C(3)–C(2) 120.7(3),
C(3)–C(4)–O(1) 119.2(3), C(28)–C(23)–C(24) 111.6(3), C(25)–C(24)–
C(23) 126.5(3), C(24)–C(25)–C(26) 117.5(3), C(27)–C(26)–C(25) 121.3(3),
C(28)–C(27)–C(26) 118.7(3), C(27)–C(28)–C(23) 124.2(3).
4
COOEt
3
– FCH2Me
O2N
Pr3i P
O
N
NO2
N
O
O2N
Ar
O
5
Scheme 2
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© 2010 Mendeleev Communications. All rights reserved.

Mendeleev Commun., 2010, 20, 39–40
(Figure 1) confirm that the reaction gives a compound having a
CH2P+Pr3i
N
NO2
CH2P+Pr3i
N
NO2
polyconjugated negatively charged moiety 5.†
O
O
The molecular structure of 5 was unambiguously established
by single-crystal X-ray diffraction analysis (Figure 1).‡
N
O
N
O
Ar
O2N
NO2 Ar
O2N
NO2
Compound 5 is a zwitterion, with the positively charged
phosphonium –CH2–P+Pr3i fragment and the negative charge
localized over long chain of the conjugated bonds. (Structure C,
Figure 2). It crystallizes in the monoclinic space group P21/c,
with two crystallographically independent molecules in the unit
cell. The two independent molecules are distinguished by only
conformations of the ethyl groups, while their main skeleton
remained practically unchanged. Therefore, only the average
values of the geometric parameters of 5 are discussed below.
As it can be suggested from the X-ray data (Figure 1), com-
pound 5 has two preferred resonance forms A and B presented
in Figure 2. The presence of the resonance form A is also con-
firmed by the fact that the para-nitro group is almost coplanar to
the C(23)–C(24)–C(25)–C(26)–C(27)–C(28) ring [the C(27)–
C(26)–N(4)–O(6) torsion angle is –11.9(5)°], whereas the
O
O
A
B
CH2P+Pr3i
N
NO2
HO
N
O
Ar
O2N
NO2
O
C
Figure 2
ortho-nitro groups [for value of the C(23)–C(24)–N(3)–O(4)
torsion angle, see above, and the C(23)–C(28)–N(5)–O(9) torsion
angle is 38.1(4)°] are substantially turned towards the same ring.
The planar structure of the central heterocycle is determined
by the extended system of conjugated bonds within the mole-
cule of 5. As a consequence, the N(1) atom adopts the trigonal-
planar configuration [sum of the bond angles at N(1) is 360°].
The (ortho-ethyl)phenyl C(5)–C(6)–C(7)–C(8)–C(9)–C(10) and
(2,4,6-trinitro)phenyl C(23)–C(24)–C(25)–C(26)–C(27)–C(28)
rings are turned by 87.1(4) and 31.4(6)°, respectively, relative
to the central ring due to the steric reasons.
†
A solution of 2,4,6-trinitrofluorobenzene (TNFB) (0.116 g, 0.52 mmol)
in CH2Cl2 (15 ml) was added dropwise with stirring to a solution of a
zwitter-ion 37 (0.210 g, 0.52 mmol) in CH2Cl2 (15 ml). The solution
immediately turned red; the colour intensity increased with time. A solu-
tion left in the closed vessel for 13 days; then, reaction mass was analyzed
for P,F-containing compounds by 19F and 31P NMR spectroscopy. In the
19F NMR spectrum, a signal at –211 ppm was found. In the 31P NMR
spectrum, the main signal was at 42.2 ppm. A volatile matter was removed
from the reaction mass at 30 °C and normal pressure and collected in a
cooled up to –40 °C CCl4 solution. In the solution obtained, 19F NMR fixed
a signal of C2H5F at –211 ppm. After removal of CH2Cl2, brown powder
was cristallized from acetone (60% yield). The subsequent crystalliza-
tion from ethyl acetate gave red crystals of compound 5, mp 245 °C.
1H NMR ([2H6]DMSO, 600.220 MHz) (for numeration of atoms herein-
after, see Figure 1) d: 7.277 [m, H-C(9)], 7.120 [d, H-C(10)], 3.360
The crystal packing of molecules in 5 is stacking along the
a axis. In the crystal, the molecules are bound by weak inter-
molecular C–H···O hydrogen bonds.
This study was supported by the Russian Foundation for
Basic Research (project no. 08-03-00196). We are grateful to
Professor F. Terrier for helpful discussions.
2
[d, H-C(13), JHP 11.8 Hz], 2.859 [ds, H-C(14), H-C(17), H-C(20),
2
3JHH 7.2 Hz, JHP 12.9 Hz], 1.355 and 1.359 [2dd, H-C(15), H-C(16),
References
H-C(18), H-C(19), H-C(21), H-C(23), 2×3JHH 7.2 Hz, 2×3JHP 15.64 Hz],
8.806 [H-C(25), H-C(27)], 2.370 [q, AB-system, H-C(11), 2JHH 14.5 Hz,
1 F. Terrier, Nucleophilic Aromatic Displacement, Wiley-VCH, Weinheim,
1991.
3
3JHH 7.6 Hz], 1.085 [t, H-C(12), JHH 7.6 Hz]. 13C NMR ([2H6]DMSO,
2 Yu. G. Gololobov, O. A. Linchenko, P. V. Petrovskii, V. N. Khrustalev
and I. A. Garbuzova, Mendeleev Commun., 2007, 17, 232.
3 Yu. G. Gololobov, O. A. Linchenko, Z. A. Starikova, I. A. Garbuzova
and P. V. Petrovskii, Izv. Akad. Nauk, Ser. Khim., 2005, 2393 (Russ.
Chem. Bul1., Int. Ed., 2005, 54, 2471).
4 Yu. G. Gololobov, O. A. Linchenko, P. V. Petrovskii, I. A. Garbuzova
and V. N. Khrustalev, Izv. Akad. Nauk, Ser. Khim., 2006, 1261 (Russ.
Chem. Bull., Int. Ed., 2006, 55, 1309).
150.925 MHz): 146.85 [C(1)], 163.34 [C(2)], 79.83 [d, C(3), 2J 5.8 Hz],
157.48 [d, C(4), 3J 3.6 Hz], 141.54 [C(5)], 134.8 [C(6)], 129.40, 129.42
[C(7), C(8)], 129.47 [C(9)], 127.17 [C(10)], 23.79 [C(11)], 14.59 [C(12)],
14.25 [d, C(13), 1J 21.8 Hz], 21.21 [d, C(14), C(17), C(20), 1J 39.3 Hz],
2
16.86 [d, C(15), C(16), C(18), C(19), C(21), C(22), J 2.9 Hz], 135.11
[C(23)], 143.68 [C(24), C(28)], 123.87 [C(25), C(27)], 141.67 [C(26)],
23.79 [C(12)], 14.59 [C(27)]. IR (KBr, pellets, n/cm–1): 1752 (νC(O)O), 1667
(νC(O)N), 1560 (conjugate bond system), 1309 (νas NO ). UV (acetone,
5 Yu. G. Gololobov, O. A. Linchenko, P. V. Petrovskii, Z. A. Starikova and
max/nm): 444.5 (e 10000). Found (%): C, 54.29; H,2 5.55; N, 11.27;
I. A. Garbuzova, Heteroatom Chem., 2007, 18 (1), 108.
l
6 Yu. G. Gololobov, O. A. Linchenko, P. V. Petrovskii, V. N. Khrustalev
and I. A. Garbuzova, Heteroatom Chem., 2007, 18 (4), 421.
7 Yu. G. Gololobov, P. V. Petrovskii, E. M. Ivanova, O. A. Linchenko,
R. Schmutzler, L. Ernst, P. G. Jones, A. Karaçar, M. Freytag and S. Okucu,
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2003, 52, 427).
8 G. M. Sheldrick, SADABS, v. 2.03, Bruker/Siemens Area Detector Absorp-
tion Correction Program, Bruker AXS, Madison, Wisconsin, 2003.
9 G. M. Sheldrick, Acta Crystallogr., 2008, A64, 112.
P, 4.96. Calc. for C28H34N5O9P (%): C, 54.63; H, 5.53; N, 11.38; P, 5.04.
Crystallographic data. The crystal of 5 (C28H34N5O9P, M = 615.57) is
‡
monoclinic, space group P21/c, at T = 100 K: a = 15.8691(15), b =
= 19.1186(17) and c = 20.2680(18) Å, b = 109.873(1)°, V = 5783.0(9) Å3,
Z = 8, dcalc = 1.414 g cm–3, F(000) = 2592, m = 0.158 mm–1. Data were
collected on a Bruker SMART APEX II CCD diffractometer [l(MoKα)-
radiation, graphite monochromator, w and j scan mode] and corrected
for absorption using the SADABS program.8 The structure was solved
by direct methods and refined by a full-matrix least squares technique on
F2 with anisotropic displacement parameters for non-hydrogen atoms.
The hydrogen atoms were placed in calculated positions and refined
within the riding model with fixed isotropic displacement parameters
[Uiso(H) = 1.5Ueq(C) for the Me groups and Uiso(H) = 1.2Ueq(C) for the
other groups]. The final divergence factors were R1 = 0.097 for 7750
independent reflections with I > 2s(I) and wR2 = 0.233 for all 11147
independent reflections, S = 1.016. All calculations were carried out
using the SHELXTL program.9
CCDC 741943 contains the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
For details, see ‘Notice to Authors’, Mendeleev Commun., Issue 1, 2010.
Received: 19th August 2009; Com. 09/3381
– 40 –