Unusual transformations of phosphoryl compounds in the Kishner reduction

Full text of DOI:10.1134/S107036321301026X

ISSN 1070-3632, Russian Journal of General Chemistry, 2013, Vol. 83, No. 1, pp. 136–137. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © M.Zh. Ovakimyan, G.C. Gasparyan, M.L. Movsisyan, M.R. Grigoryan, 2013, published in Zhurnal Obshchei Khimii, 2013, Vol. 83,
No. 1, pp. 144–145.
LETTERS
TO THE EDITOR
Unusual Transformations of Phosphoryl Compounds
in the Kishner Reduction
M. Zh. Ovakimyan, G. C. Gasparyan, M. L. Movsisyan, and M. R. Grigoryan
Scientific and Technological Center of Organic and Pharmaceutical Chemistry,
National Academy of Sciences of the Republic of Armenia, pr. Azatutyana 26, Yerevan, 0014 Armenia
e-mail: mickael.movsisyan@gmail.com
Received April 16, 2012
DOI: 10.1134/S107036321301026X
Recently we found that triphenyl-2-methyl-2-phenyl-
hydrazinoethylphosphonium bromide formed in the
reaction of triphenylprop-2-enylphosphonium bromide
I [1] with phenylhydrazine was dehydrogenated in the
presence of sodium carbonate under stirring for 6 h in
chloroform at room temperature to give triphenyl-2-
oxopropylphosphonium bromide phenylhydrazone in a
50% yield [2].
zone analog of the same phosphonium salt we studied
the reaction of salt I with an aqueous hydrazine in the
presence of sodium carbonate in chloroform at 30°C.
Unexpectedly, propyldiphenylphosphine oxide II was
obtained in 50% yield as the reaction product along with
the doubly N-alkylated adduct. Probably the formation of
II occurs through an intermediate diphenyl-2-methyl-2-
hydrazinoethylphosphine oxide III. The latter undergoes
successive dehydrogenation and denitrogenation as follows:
Aiming to obtain the similar unsubstituted hydra-
NH2NH2 H2O
Na2CO3
+
NHNH2
+
+
Ph3P
Ph3P
Ph3P
Br−
Br−
Br−
V
I
H
N
OH−
NHNH2
−N2
−H2
N
Ph2P
O
Ph2P
O
Ph2P
O
−C6H6
II
III
IV
Theoretically, there is a possibility of the inter-
mediate formation of compound IV via the alkaline
hydrolysis of azophosphonium salt derived through the
direct dehydrogenation of salt V.
reflux in acetonitrile it also transforms into propyl-
diphenylphosphine oxide in a low yield (30%). The
residual phosphine oxide was recovered. Obviously,
the low product yield is caused by the difficult addition
of hydrazine to diphenylvinylphosphine oxide.
The phosphine oxide II was obtained with almost
the same yield by the reaction of the phosphonium salt
I with ethylhydrazine in an aqueous medium in the
presence of acetic acid at 50°C. The reaction probably pro-
ceeds according to the same scheme, however in this case
the reaction is accompanied by the ethylene formation.
According to the experimental results, the
elimination of the molecular nitrogen occurs in the
phosphoryl intermediate IV.
The studied reaction is actually related to the
Kishner reaction with the only difference that the latter
usually proceeds at high temperatures. It can be
assumed that the presence of the phosphoryl group in
We found that diphenylprop-1-enylphosphine oxide
does not react with aqueous hydrazine at 30°C, but at
136

UNUSUAL TRANSFORMATIONS OF PHOSPHORYL COMPOUNDS
137
the substrate favors significantly the denitrogenation
reaction, due likely to the formation of the hydrogen
bonds between the phosphoryl oxygen and the hyd-
rogen atom of the azo-groups.
with anhydrous benzene and dried in a vacuum to
afford triphenylprop-1-enylphosphonium bromide [1].
Yield 0.35 g (35%), mp 213–214°C. The benzene
extract was concentrated, and the residue was recrys-
tallized to afford propyldiphenylphosphine oxide.
Yield 0.3 g (47.3%), mp 99–100°C. The NMR spectral
parameters are completely consistent with the known
data.
Reaction of salt I with aqueous hydrazine. A
mixture of 5.2 mmol of salt I, 0.28 g (5.2 mmol) of
60% aqueous hydrazine, and 5.2 mmol of dry sodium
carbonate in 15 ml of chloroform was stirred for 6 h at
30°C and then diluted with water. The organic layer
was separated, dried over MgSO4, filtered, and con-
centrated. The residue was washed with anhydrous
benzene, dried in a vacuum, and recrystallized from an
ethyl acetate–isopropanol mixture to afford N,N-bis-
(triphenylisopropylphosphoniodibromido)hydrazine.
Reaction of diphenylprop-1-enylphosphine oxide
with aqueous hydrazine. A mixture of 4.5 mmol of
diphenylprop-1-enylphosphine oxide [4] and 0.35 g
(6 mmol) of 60% aqueous hydrazine in 15 ml of
acetonitrile was heated for 6 h at 75°C. Then the
solvent was removed, and the residue was extracted
with water and benzene. The benzene layer was dried
over MgSO4 and concentrated. The fractional recrys-
tallization of the residue from benzene–petroleum
ether results in propyldiphenylphosphine oxide. Yield
0.33 g (30%), mp 99–100°C. The NMR spectral param-
eters are completely consistent with the known data.
1
Yield 1.2 g (30%), mp 220°C. H NMR spectrum
3
(DMSO-d6), δ, ppm (J, Hz): 1.28 d (6 Н, СН3, JНН
3
3
6.3), 3.45 d.q.t [2Н, СН(СН3)N, JНН 6.3, JНН 6.2,
2
3
3JРН 9.5), 3.82 d.d.d [2Н, Р+(На)Нb, JНН 15.6, JНН 6.2,
2
3
2JPН 11.6], 4.17 d.d.d [2H, Р+На(Нb), JНН 15.6, JНН
6.2, 2JPН 13.5], 7.6–8.0 m (30 Н, Р+Рh3), 9.15 br.s (2H,
NH2). 31P NMR spectrum (DMSO-d6): δp 28.50 ppm.
Found, %: Р 7.05; Br 19.98. C42H44N2P2Br2. Cal-
culated, %: Р 7.77; Br 20.05.
Also diphenylprop-1-enylphosphine oxide was
isolated. Yield 0.7 g (64%), mp 127–128°C.
1
The H and 31P NMR spectra were recorded on a
The benzene extract was concentrated, and the
residue was recrystallized from a benzene–petroleum
ether mixture to afford propyldiphenylphosphine oxide
Varian Mercury-300 spectrometer [300.077 MHz (1H),
121.47 MHz (31P)] at 303 K relative to internal TMS
and external 85% H3PO4, respectively.
1
[3]. Yield 0.62 g (49.3%), mp 99–100°C. H NMR
spectrum (DMSO-d6), δ, ppm (J, Hz): 1.15 t (3Н, СН3,
3JНН 7), 1.42–1.68 m (2Н, СН2СН3), 2.20–2.43 m (2Н,
РСН2), 7.4–7.7 m (10Н, РРh2). 31P NMR spectrum
(DMSO-d6): δp 30.77 ppm.
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and Indzhikyan, M.G., Zh. Obshch. Khim., 2005,
vol. 75, no. 7, p. 1132.
Reaction of salt I with ethylhydrazine. A mixture
of 2.6 mmol of salt I, 2.6 mmol of acetic acid, and
2.6 mmol of ethylhydrazine in 10 ml of water was
heated for 8 h at 55–57°C and extracted with chloro-
form. The chloroform extract was dried over MgSO4,
filtered, and concentrated. The residue was washed
3. Buss, A.D. and Warren, S., J. Chem. Soc. Perkin Trans. 1,
1985, p. 2307.
4. Horner, L., Ertel, I., Ruprecht, H., and Belovsky, O.,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 1 2013