Condensation of N-substituted alkyl(dibutoxyphosphoryl)acetimidates with tribromoacetaldehyde

Article abstract of DOI:10.1134/S1070363210030114

N-Substituted alkyl(dibuthoxyphosphoryl)acetimidates enter into the reaction with tribromoacetaldehyde under mild conditions without catalyst to form products of addition to the carbonyl group, N-substituted ethyl-(4,4,4-tribromo-3-hydroxy-2-dibutoxyphosp

Full text of DOI:10.1134/S1070363210030114

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 3, pp. 440–441. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.E. Shishkin, E.V. Mednikov, Yu.V. Popov, O.V. Anishchenko, M.I. Bondareva, 2010, published in Zhurnal Obshchei Khimii, 2010,
Vol. 80, No. 3, pp. 417–418.
Condensation of N-Substituted
Alkyl(dibutoxyphosphoryl)acetimidates
with Tribromoacetaldehyde
V. E. Shishkin, E. V. Mednikov, Yu. V. Popov, O. V. Anishchenko, and M. I. Bondareva
Volgograd State Technical University, pr. Lenina 28, Volgograd, 400131 Russia
е-mail: tons@vstu.ru
Received August 4, 2009
Abstract―N-Substituted alkyl(dibuthoxyphosphoryl)acetimidates enter into the reaction with
tribromoacetaldehyde under mild conditions without catalyst to form products of addition to the carbonyl
group, N-substituted ethyl-(4,4,4-tribromo-3-hydroxy-2-dibutoxyphosphoryl)butanimidates.
DOI: 10.1134/S1070363210030114
Recently we established that N-substituted alkyl
(dialkoxyphosphoryl)acetimidates showed СН-acidic
properties due to the lability of methylene hydrogen
atoms located between electron-withdrawing dialkoxy-
phosphoryl and imine groups [1]. Utilizing these
properties, we developed new methods of preparation
of phos-phorylated imidates containing various
functionalities [2, 3]. Extending this direction and
continuing the study of CH-acidic properties of
phosphorylated imidates, we examined condensation
of N-substituted alkyl(dialkoxyphosphoryl)acetimidates
with tribromoacetaldehyde. The products of con-
densation of trihaloaldehydes with different phos-
phorus-nitrogen containing compounds are known to
exhibit high pesticide and fungicidal activities [4].
As the investigation subjects we used imidates
containing butoxy groups on the phosphorus atom, as
the least toxic, and also acetyl, benzoyl, trimethylsilyl,
and dimethoxyphosphoryl substituents at the nitrogen
atom. These imidates are known to show a versatile
biological activity. It is known that condensation of
CH-acidic compounds with carbonyl compounds
(Knoevenagel reaction) occurring in the presence of
catalysts with water elimination, is a special case of
aldol-crotonic condensation, where the used methylene
components have especially high acidity owing to the
two reactive hydrogen atoms. In the case of N-
substituted phosphorylated acetimidates the condensa-
tion of the latter with tribromoacetaldehyde proceeds
under mild conditions free of catalysts and without
water elimination. This is due to weaker СН-acidic
properties of phosphorylated imidates in comparison
with the malonate.
N-Substituted ethyl(dibutoxyphosphoryl)acetimidates
react with tribromoacetaldehyde to yield the products
of addition to the carbonyl group, N-substituted ethyl-
(4,4,4-tribromo-3-hydroxy-2-dibutoxyphosphoryl)-
butanimidates.
The reaction with tribromoacetaldehyde proceeds in
the absence of catalyst due to the high electrophilicity
of the carbonyl group activated with the strong
inductive electron-withdrawing effect of the tribromo-
methyl group.
(C4H9O)2P(O)CH2C=NR
OC2H5
CBr3C=O
H
+
Reaction of N-substituted phosphorylated imidates
with tribromoacetaldehyde was carried out at the molar
ratio 1:1. This reaction occurs with heat evolution.
Imidates in these reactions differ little from each other
by reactivity. All the obtained N-substituted ethyl-
(4,4,4-tribromo-3-hydroxy-2-dibutoxyphosphoryl)-
butanimidates are viscous yellow liquids, well soluble
(C4H9O)2P(O)CH C(=NR)OC2H5
CBr3CH
OH
R = CH3C(O); C6H5C(O); (CH3)3Si; (CH3O)2P(O).
440

CONDENSATION OF N-SUBSTITUTED
441
in alcohol, dioxane, poorly soluble in the saturated
hydrocarbons, and insoluble in water. Structure and
composition of the compounds obtained were
confirmed by the elemental analysis data, molecular
refraction, and IR spectroscopy.
Ethyl-N-trimethylsilyl-(4,4,4-tribromo-3-hydroxy-
2-dibutoxyphosphoryl)butan-imidate was prepared
similarly from 5 g (0.014 mol) of ethyl-N-trimethyl-
silyl(dibutoxyphosphoryl)acetimidate and 3.93
g
(0.014 mol) of tribromoacetaldehyde. Yield 7.6 g
(86%), nD20 1.4886, d420 1.4162, MRD 127.89, calc.
128.41. Found, %: N 2.23, P 4.71. С17Н31О5PNBr3Si.
Calculated, %: N 2.22, Р 4.94.
Besides the absorption bands characteristic of the
initial N-substituted dialkoxyphosphorylacetimidates
at 1660–1675 (С=N), 1220-1260 (P=O), 1740 (C=O),
1090–1116 (C–O–C), and 980–1060 cm–1 (P–O–C),
the IR spectra of the synthesized compounds contain
also a wide band at 3190–3280 cm–1 belonging to the
stretching vibrations of ОН-group and a strong band at
740–742 cm–1 originating from С–Br bond vibrations.
Ethyl-N-benzoyl-(4,4,4-tribromo-3-hydroxy-2-
dibutoxyphosphoryl)butanimidate was prepared
similarly from 4 g (0.01 mol) of ethyl-N-benzoyl(dibu-
toxyphosphoryl)acetimidate and 2.8 g (0.01 mol) of
tribromoacetaldehyde. Yield 6 g (91%), nD20 1.5354,
d420 1.3319, MRD 155.07, calc. 155.55. Found, %: N
2.25, P 4.71. С21Н31О6PNBr3. Calculated, %: N 2.11,
Р 4.67.
Hence, the approach to N-substituted ethyl-(4,4,4-
tribromo-3-hydroxy-2-dibutoxyphosphoryl)butanimidates
was elaborated. This method is characterized by the
simplicity of the experimental conditions and high
yields of the target products (86–93%).
Ethyl-N-acetyl-(4,4,4-tribromo-3-hydroxy-2-di-
butoxyphosphoryl)butanimidate was prepared
similarly from 5 g (0.016 mol) of ethyl-N-acetyl(di-
butoxyphosphoryl)acetimidate and 4.4 g (0.016 mol)
of tribromoacetaldehyde. Yield 9 g (93%), nD20 1.4884,
d420 1.3186, MRD 114.13, calc. 114.82. Found, %: N
2.38, P 5.62. С16Н29О6PNBr3. Calculated, %: N 2.33,
Р 5.15.
EXPERIMENTAL
The IR spectra were recorded on a SPECORD М 82
instrument. Spectra of liquid substances were
registered from a thin layer.
Ethyl-N-dimethoxyphosphoryl-(4,4,4-tribromo-
3-hydroxy-2-dibutoxyphosphoryl)-butanimidate.
To a solution of 3 g (0.0077 mol) of ethyl-N-dime-
thoxyphosphoryl(dibutoxyphosphoryl)acetimidate in
5 ml of dioxane was added a solution of 2.2 g
(0.0077 mol) of tribromoacetaldehyde in 1 ml of
dioxane. At mixing the solution self-heated and turned
bright yellow. The reaction mixture was allowed to
stand for 2 h at 40°С, after that the solvent was
removed. The crude product was distilled (Рres 1–
2 GPa, Тbath 40°С). Yield 4.6 g (89%), nD20 1.4872, d420
1.5899, MRD 120.88, calc. 121.62. Found, %: N 2.23, P
8.89. C16H32O8P2NBr3. Calculated, %: N 2.09, Р 9.28.
REFERENCES
1. Shishkin, V.Е., Mednikov, Е.V., Anishchenko, О.V.,
and No, B.I., Dokl. Ross. Akad. Nauk, 2001, vol. 380,
no. 5, p. 645.
2. Shishkin, V.Е., Mednikov, Е.V., Anishchenko, О.V.,
and No, B.I., RF Patent no. 220328, MPK 7C 07 F9/40,
Volgograd. Gos. Univ., 2003.
3. Shishkin, V.Е., Mednikov, Е.V., and Anishchenko, О.V.,
Zh. Obshch. Khim., 2005, no. 3, p. 411.
4. Purdela, D. And Vylchanu, R., Khimiya organicheskikh
soedinenii fosfora (Chemistry of Organophosphorus
Compounds), Moscow: Khimiya, 1972.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 3 2010