Reaction of 5,7-dinitrobenzofuroxane with triphenylphosphine

Full text of DOI:10.1134/S1070428012080180

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 8, pp. 1133−1134. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © I.V. Galkina, M.P. Spiridonova, E.V. Tudrii, E.A. Berdnikov, L.M. Yusupova, R.A. Cherkasov, V.I. Galkin, 2012, published in Zhurnal
Organicheskoi Khimii, 2012, Vol. 48, No. 8, pp. 1133−1134.
SHORT
COMMUNICATIONS
Reaction of 5,7-Dinitrobenzofuroxane
with Triphenylphosphine
I. V. Galkinaa, M. P. Spiridonovaa, E. V. Tudriia, E. A. Berdnikova, L. M. Yusupovab,
R. A. Cherkasova, and V. I. Galkina
aKazan (Privolzhskii) Federal University, Kazan, 420008 Russia
e-mail: vig54@mail.ru
bKazan State Technological University, Kazan, Russia
Received March 14, 2012
DOI: 10.1134/S1070428012080180
We showed previously that in reaction of triphe-
nylphosphine with 5,7-dichloro-4,6-dinitrobenzo-
furoxane [1] a stable diphosphabetain was obtained. We
describe here a similar reaction of 5,7-dinitrobenzofu-
roxane (I) lacking chlorine atoms and resulting in the
same conditions in the formation of NH-radical II stable
already for the last three years.
According to the data of ESR spectroscopy the reac-
tion starts with the formation of NO-centered benzofu-
roxane radical whose ESR spectrum changes with time.
The integral intensity of the ESR signal grows at the
beginning of the reaction, and in 20 min decreases to
zero. Within two weeks the reaction mixture has turned
into plate-like dark-red crystals which according to XRD
O
H
Ph3P
H
O2N
N
N
C2H5OH_(C2H5)2O
_NO. , _Ph3P=O
2 PPh3
+
O
O
.
N
N
H
H
O2N
NO2
O
II
I
study have the structure of phosphorus(II) ylide. The
data of 31Р NMR spectrum and of the elemental analysis
confirm this conclusion.
intermediates whose structure now is not yet possible
to establish, and their subsequent transformation results
in the final product, stable NH-radical II. Its stability
originates from the resonance of structures where the
unpaired electron is localized on diverse atoms.
IR spectrum from the mull in mineral oil contains a
characteristic absorption band of the NH group in the
region 3266 cm–1 and the absorption bands of С=N and
С=С at 1740 and 1600 cm–1 respectively. According to
TG/DSC compound II has mp 71.3°С, decomposition
temperature 177.7°С, and these parameters have not
changed within 3 years.
6-Nitro-7-oxo-4-(triphenylphosphoranylidene)-
1,4,7-dihydro-2,1,3-benzoxadiazole-radical (II). To
a solution of 0.1 g (0.442 mmol) of benzofuroxane I
in 10 ml of the mixture ethanol–ether, 1:3, was added
dropwise in an argon atmosphere 0.232 g (0.885 mmol)
of triphenylphosphine in 10 ml of the same solvent. In
the course of the reaction the color o the reaction mixture
We believe that the most probable scheme of
the reaction involves the formation of free radical
1133

GALKINA et al.
Ph3P
1134
Ph3P
Ph3P
.
N
H
H
H
N
N
O
O
O
.
N
H
N
N
H
O2N
O2N
O2N
.
H
O
O
O
Ph3P +
Ph3P +
N_
N_
H
H
.
O
O
.
N
H
N
H
O2N
O2N
O
O
changed from light-yellow to dark red. In two weeks a
druse of bright red crystals formed in the reaction mix-
ture, it was separated and washed with ethanol and ether.
Yield 0.235 g (71%), mp 71.3°С, t.decomp. 177.7°С.
IR spectrum (mull in mineral oil), ν, cm–1: 3266, 1740,
1629, 1600, 1430. 31Р NMR spectrum (DMSO-d6), δ,
ppm: 20.77. Found, %: C 65.54; Н 4.03; N 9.77; Р 7.37.
C24H17N3O4P. Calculated, %: С 65.16; H 3.85; N 9.50;
Р 7.05. The structure is confirmed by XRD analysis; its
results will be published elsewhere.
31Р NMR spectrum was registered on a spectrometer
Avanse-400 Bruker at operating frequency on 31Р nuclei
161.68 MHz, external reference 85% Н3РО4 (31Р). ESR
spectra were taken on spectrometrs Varian Е-12 and
Bruker Elexys 680, SHF 9.7 GHz. In the study a mixture
of anhydrous solvents–ethyl ether, 1:3, was used. IR
spectra were recorded on an IR Fourier spectrophotometer
Tensor 27 Bruker applying an IR microscope Hyperion
2000, Bruker (Germany). The XRD experiment was car-
ried out on a diffractometer Bruker SMART 1000 CCD.
TG-DSC measurements were performed on an instrument
NETZSCH STA449C TGA/S6TA85/E in the temperature
range 20–400°С, heating rate 10 deg/ min in an argon.
REFERENCES
1. Galkina, I.V., Tudriy, E.V., Kataeva, O.N., Usupova, L.M.,
Luftmann, H., and Galkin V.I., Phosph. Sulfur, Silicon,
Relat. Elem. 2009, vol. 184, p. 987.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 48 No. 8 2012