Russian Journal of General Chemistry, Vol. 71, No. 2, 2001, pp. 313 314. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 2, 2001,
pp. 343 344.
Original Russian Text Copyright
2001 by M. Gazizov, Safina, Khairullin, K. Gazizov.
LETTERS
TO THE EDITOR
Reaction of Trialkyl Phosphites with Monoacylals
of Dichloro- and Trichloroacetic Acids
M. B. Gazizov, G. G. Safina, R. A. Khairullin, and K. M. Gazizov
Kazan State Technological University, Kazan, Tatarstan, Russia
Received May 4, 2000
We found a new reaction between trialkyl phos-
phites I and 1-ethoxyethyl dichloro- and trichloro-
ethanoates II, resulting in formation of 1-ethoxyethyl-
phosphonates III and alkyl dichloro- and trichloro-
ethanoates IV. This result differs radically from the
previously reported results of reactions of compounds
I with ethyl trichloroacetate [1], halogen-substituted
acetyl chlorides [2], and trichloroacetic anhydride
and its diacylal [3], the major products of which were
substituted vinyl phosphates.
mixture was stirred at that temperature for 2 h. The
31P NMR spectrum of the reaction mixture showed
two singlets with
27 and 1 ppm in a 1.5:1.0 ratio,
assigned to compoPunds IIIa and VIa. Volatile pro-
ducts were collected in a liquid nitrogen trap. Distilla-
tion of the residue gave three fractions. The first frac-
tion (1.87 g) was trimethyl phosphate, bp 75 76 C
(10 mm), n2D0 1.3995 {published data [4]: bp 62 C
(5 mm), n2D0 1.3963}; 3.5 ppm, d (MeO, J 11 Hz),
1 ppm. The second fraction, 1.31 g, was a mixture
oPf compounds IIIa and VIa (the integral intensity
We propose that trialkyl phosphite primarily
attacks the electrophilic methine carbon atom in com-
pound II to form quasiphosphonium salt V. The latter
is dealkylated under the action of the dichloro- or tri-
chloroalkanoate anions.
ratio of the signals with
27 and 1 ppm was 1.3:1).
The third fraction, 2.45 Pg, was product IIIa.
Dimethyl 1-ethoxyethylphosphonate (IIIa). bp
1
96 98 C (0.45 mm). H NMR spectrum (CDCl3), ,
ppm: 4.15 m (1H, PCH), 3.7 d (6H, POMe, J
11.5 Hz), 3.6 q (2H, OCH2, J 7.5 Hz), 1.2 d.d (3H,
CHMe, J 7.5 and 18.7 Hz), 1.02 t (3H, CH2Me, J
(RO)3P + MeCH(OEt)OCOXCl2
I
II
Cl2XCCOO (RO)3P+CH(OEt)Me
7.5 Hz);
27 ppm. Found P, %: 17.06. C6H15O4P.
CalculatedP P, %: 17.03.
V
Distillation of the condensate in the trap gave
2.15 g of methyl trichloroacetate, bp 43 44 C
(11 mm), n2D0 1.4579 {published data [5]: bp 44.5 C
(RO)2P(O)CH(OEt)Me + Cl2XCCOOR,
III
IV)
(12 mm), n2D0 1.4572}. H NMR spectrum (CDCl3), ,
1
R = Me (a), Et (b) (I, III, V); X = Cl (a), H (b) (II, IV).
ppm: 3.95 s (OMe).
The observed reaction pathway is evidently con-
nected with increased lability of the acyloxy group, as
a result both of the electron-acceptor effect of chlorine
substituents and of the presence of the 1-ethoxy group
in the ethyl radical. Note that among the reaction
products we found a considerable amount of trialkyl
phosphate VI, but its formation pathway could not be
elucidated.
Reaction of triethyl phosphite (Ib) with 1-ethoxy-
ethyl dichloroethanoate (IIb). A mixture of 5.3 g of
triethyl phosphite and 6.42 g of compound IIb was
heated first at 50 C for 2 h and then at 80 C for 2.5 h,
until the phosphite odor disappeared. The 31P NMR
spectrum of the reaction mixture contained two sin-
glets with
24 and 1 ppm in a 1.4:1.0 ratio.
P
Vacuum distillation of the reaction mixture gave three
fractions with bp 48 98 C (1.80 g), 98 103 C
(2.81 g), and 119 129 C (1.9 g). According to H and
31P NMR data, the latter two fractions were respective-
Reaction of trimethyl phosphite (Ia) with
1-ethoxyethyl trichloroethanoate. Trimethyl phos-
phite (Ia), 4.66 g, was added dropwise at a tempera-
ture below 23 C to 8.05 g of compound IIa, and the
1
ly 1:1 and 1.7:1 mixtures of compounds IIIb and
1070-3632/01/7102-0313$25.00 2001 MAIK Nauka/Interperiodica
Gazizov
