Reactions of benzaldehyde dimethylhydrazone with phosphorous acids

Full text of DOI:10.1134/S1070363213110303

ISSN 1070-3632, Russian Journal of General Chemistry, 2013, Vol. 83, No. 11, pp. 2119–2121. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © A.A. Fazullina, L.V. Ryapisova, L.B. Kashevarova, S.V. Fridland, 2013, published in Zhurnal Obshchei Khimii, 2013, Vol. 83,
No. 11, pp. 1929–1931.
LETTERS
TO THE EDITOR
Reactions of Benzaldehyde Dimethylhydrazone
with Phosphorous Acids
A. A. Fazullina, L. V. Ryapisova, L. B. Kashevarova, and S. V. Fridland
Kazan National Research Technological University, ul. K. Marksa 68, Kazan, Tatarstan, 420015 Russia
e-mail: rialaiam@pisem.net
Received November 26, 2012
DOI: 10.1134/S1070363213110303
As shown previously, reactions of dimethylhyd-
razones of chloro- and nitrobenzaldehydes with phos-
phorous acids in the presence of alkali metal
alcoholates and triethylamine as catalysts (as well as
without the catalysts) led to the corresponding salts
rather than to phosphonates [1].
C
O
H
C
N N(CH3)2
H
(CH3)2N NH2 +
−H2O
I
Phosphorylated hydrazones could only be obtained
via the intermediate formation of α-oxyphosphonates [2].
In the classic Pudovik reaction, the bases (various
amines) are used as catalysts. However, the reaction in
the presence of triethylamine as a catalyst did not lead
to the phosphonates.
The attempt to reduce the dealkylating ability of
dimethylamino group of hydrazones by prior synthesis
of dimethylammonium salt of hydrazone also led to
phosphoramidate instead of the desired phosphonate
[3].
Trimethylchlorosilane is known to affect the reac-
tions of phosphorous acids with olefins resulting in
phosphonates. In particular, it reacts with diethyl
phosphite to form trimethylsilyldiethyl phosphite and
hydrogen chloride, changing pH of the medium. It is
known that the presence of acidic impurities in
phosphoric acids promoted the phosphonates forma-
tion [4]. Basing on that knowledge, we introduced the
catalytic amount of trimethylchlorosilane to the
reaction of benzaldehyde dimethylhydrazone I with
diethyl phosphite. As a result, diethyl(1-phenyl-1-di-
methylhydrazino)phosphonate II was isolated in the
form of white crystalline substance. Its structure was
confirmed by elemental analysis, IR, and 31P NMR
spectroscopy data.
The peculiarities of the above-mentioned processes
were due to the effects of the aromatic ring substi-
tuents [3]. Therefore, it was of interest to investigate
the reactions of unsubstituted benzaldehyde dimethyl-
hydrazone with diethyl and diphenyl phosphites.
Benzaldehyde N,N-dimethylhydrazone
I
was
prepared via the reaction of benzaldehyde with unsym-
metrical dimethylhydrazine.
The reactions of the so obtained hydrazone with
diethyl and diphenyl phosphites were performed under
different conditions.
H
H
H
N
+
C
N N(CH3)2
C
N(CH3)2
+ ClSi(CH3)3
Cl−
H
P(OR)2
O
(RO)2P
O
B
Si(CH3)3
II, III
R = C2H5 (II), C6H5 (III).
2119

2120
FAZULLINA et al.
When phosphorylation of I was performed at 90–
In the case of diphenyl phosphite, which was not
110°C, the reactions with both diethyl and diphenyl phos-
phites resulted in benzonitrile IV. This could be ex-
plained by the fact that at high temperatures the qua-
ternary hydrazone A did not form the intermediate adduct
B, and the reaction started with the N–N bond rupture.
The reaction scheme could be represented as follows.
capable of dealkylation, the reaction with hydrazone I
proceeded in the absence of trimethylchlorosilane to
give the target phosphonate III. However, the reaction
was very slow. Introduction of trimethylchlorosilane
significantly accelerated it.
(RO)2P H + ClSi(CH3)3
+ HCl
(RO)2P
O
Si(CH3)3
H
O
H
+
N N(CH3)2
C
C
N
N(CH3)2
+ HCl
H Cl−
А
H
C
H
+
N N(CH3)2
Cl−
C
N
+ HN(CH3)2 + (RO)2P H + ClSi(CH3)3
O
(RO)2P
O
B
Si(CH3)3
Benzaldehyde N,N-dimethylhydrazone (I). A mix-
ture of 12.4 g (0.11 mol) of benzaldehyde and 17.7 g
(0.29 mol) of N,N-dimethylhydrazine was stirred at
room temperature during 2 h and then at 45°C during
1 h. The target hydrazone was isolated by vacuum
distillation. Yield 66.78% (11.56 g), bp 119–120°C
(15 mm Hg), nD20 1.5986, d420 0.9983 g cm–3. IR
spectrum, ν, cm–1: 1570 (C=N), 740, 1520, 1600
(С6Н5). Found, %: С 72.23; Н 8.02; N 18.45. С7Н12N2.
Calculated, %: С 72.97; Н 8.11; N 18.92.
and 1–2 drops of trimethylchlorosilane were added to
5.1 g (0.04 mol) of I. The mixture was stirred during
1 h at 60°C and distilled under reduced pressure. Yield
38% (4.93 g), bp 107–109°C (22 mm Hg). IR spec-
trum, ν, cm–1: 1270 (Р=О), 3300–3400 (NH). 31Р NMR
spectrum: δP 20.74 ppm. Found, %: С 64.98; Н 6.35; N
7.54; Р 8.23. С21Н23N2O3P. Calculated, %: С 65.8; Н
6.27; N 7.31; Р 8.09.
Benzonitrile (IV). a. A mixture of 6 g (0.04 mol)
of I, 7.3 g (0.05 mol) of diethyl phosphite, and 0.5 g of
trimethylchlorosilane was stirred for 3 h at 89–90°C,
and then distilled under reduced pressure. Yield
19.38% (0.81 g), bp 105–107°C (20 mm Hg), nD20
1.5246, d420 0.9991 g cm–3. IR spectrum, ν, cm–1: 2225
(С≡N), 740, 1520, 1600 (С6Н5). Found, %: С 85.51; Н
1.0; N 14.02. С7Н5N. Calculated, %: С 84.85; Н 1.01;
N 14.14.
Diethyl 1-phenyl-1-dimethylhydrazinophospho-
nate (II). 4.7 g (0.03 mol) of diethyl phosphite and 1–
2 drops of trimethylchlorosilane were added to 5.1 g
(0.04 mol) of I. The mixture was stirred during 3 h at
60°C. The precipitate was washed with acetone and
vacuum-filtered off. Yield 55% (2.6 g), mp 127°C. IR
spectrum, ν, cm–1: 1280 (Р=О), 3300–3400 (NH). 31Р
NMR spectrum: δP 18.26 ppm. Found, %: С 53.55; Н
8.15; N 9.54; Р 10.23. С13Н23N2O3P. Calculated, %: С
54.56; Н 8.36; N 9.76; Р 10.8.
b. A mixture of 4.2 g (0.028 mol) of I, 8.63 g
(0.037 mol) of diphenyl phosphite, and 0.5 g of tri-
methylchlorosilane was stirred during 3 h at 109–110°C,
and then distilled under reduced pressure. Yield
52.40% (4.45 g), bp 82–84°C (13 mm Hg). IR spec-
Diphenyl
1-phenyl-1-dimethylhydrazinophos-
phonate (III). 8 g (0.03 mol) of diphenyl phosphite
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 11 2013

REACTIONS OF BENZALDEHYDE DIMETHYLHYDRAZONE
2121
trum, ν, cm–1: 2229 (С≡N), 740, 1520, 1600 (С6Н5).
Found, %: С 85.01; Н 1.0; N 14.35. С7Н5N. Cal-
culated, %: С 84.85; Н 1.01; N 14.14.
and Fridland, S.V., Zh. Obshch. Khim., 1997, vol. 67,
no. 12, p. 2061.
2. Ryapisova, L.V., Kashevarova, L.B., Fridland, S.V., and
Shaikhiev, I.G., Zh. Obshch. Khim., 2000, vol. 70,
no. 10, p. 1631.
IR spectra (suspension in mineral oil) were
recorded with UR-20 spectrometer. 31P NMR spectra
were registered with Bruker WM-250 spectrometer
operating at 101.27 MHz.
3. Frolov, V.V., Candidate Sci. (Chem.) Dissertation,
Kazan, 2008.
4. Sobanov, A.A., Zolotukhin, A.V., Galkina, I.V., and
Galkin, V.I., Cherkasov R.A., Russ. J. Gen. Chem.,
2006, vol. 76, no. 3, p. 421.
REFERENCES
1. Ryapisova, L.V., Kashevarova, L.B., Shaikhiev, I.G.,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 11 2013