.beta.,.beta.-DIACYLOXYETHANOLS ET PROCEDE POUR LEUR PREPARATION

.beta.,.beta.-DIACYLOXYETHANOLS AND PROCESS FOR THEIR PREPARATION

Abrégé anglais

ABSTRACT OF THE DISCLOSURE:
The invention relates to a process for the preparation
of .beta.,.beta.-diacyloxyethanols of the general formula:
<IMG>
wherein X and X', equal or different, are alkyl of 1 to 5 carbon
atoms, process which comprises reacting a compound of the type
<IMG>
with an excess of carboxylic acid of the type HOCOX' (X) wherein
X and X' have the same meaning as defined above. These new
chemical compounds according to the present invention find
application for instance in the preparation, through hydrolysis,
of the glycoaldehyde.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. .beta.,.beta.-diacyloxyethanols of the general formula
<IMG>
wherein X and X', equal or different, are alkyl of 1 to 5 carbon
atoms.
2. A process for the preparation of compounds according
to claim 1, consisting in reacting a compound of the type
<IMG>
with an excess of carboxylic acid of the type HOCOX' (X) wherein
X and X' have the same meaning as defined in claim 1.
3. A process according to claim 2, characterized in
that the reaction is carried out at temperatures of between +5
and +100°C.
4. A process according to claims 2 and 3, characterized
in that the reaction is carried out in the presence of an
inert solvent selected among hydrocarbons, halogenated hydrocarbons
and ethers.

Description

105~9~
The present invention refers to a series of new
chemical co~lpounds, the~ diacyloxyethanols as well as the
process for their preparation.
More particularly the subject of the present invention
consists of a new class of chemical compounds that can be
schematized by the following formula
OH
~ OCOX'
C 2 CH
OCOX
where X and X', equal or different are alkyl of 1 to 5 carbon
atoms, and find application for instance in the preparation,
through hydrolysis, of the glycoaldehyde which itself is an
intermediate for the synthesis of solvents,plastics, d-l-serine,
or else. Furthermore, concerning the preparation of d-l-serine,
` which is effected through the Strecker reaction and its varieties,
the reaction may be directly effected with advantage on the
~,~-diacyloxy-(or ~,~ -diaryloxy)-ethanols themselves as
specified in other pending Canadian application no. 224,347 filed
on April 10, 1975, as the hydrolysis to aldehyde takes place in
situ, because of the alkaline conditions of the reaction itself.
According to the present invention, the above named
compounds are prepared by reacting compounds of formula
\
OCOX ( X ' )
with a strong excess of carboxylic acid of the type HOCOX' (HlOCOX)
wherein X and X' have the above mentioned meaning, as such, or
possibly diluted with an inert solvent, chosen, e.g. among hydro-
carbons, halogenated hydrocarbons and ethers.
The vinyl ester epoxydes, used as starting material may
-,, ,, ~

lOSl~l9
be obtained, ~or instance, according to slmple and eco~omical
method~ a6 described in copending applications of the same ap-
plicant.
The reaction subJect o~ the invention takes place at
temperature~ between +5 and 100C, preferably around 10C accor-
ding to the procedures described in the following example ~hich
however must be not considered as limiting the scope of the in-
vention.
Example
A solution of 1.02 g vinylacetatepo~ide i~ 5 ml of
glacial acetio acid was left for 7 days at about 10C in a closed
flask. At the end o~ this peried a n.m.r. (C6D6) test e~fected
on the reaction mi~ture shows as only signals, in addition to
those of the acid, the ones that can be ascribed to the 2,2-
diacetoxyethanol ~ ~ 3.80 (d, 2X, CH2) and 7.05 p.p.m. (t~lH, C~)
and to the presence of Emall quantities o~ a secondary product,
the monoacetoxyaldehyde r~ 4.15 (s, 2H,-C~ ) and 9.10 p.p.m.
(8, lH, CH0) 7.
~ o the end reaction mixturè diluted in 30 ml of methyle-
ne chloride, 7 g sodium bi-carbonate are added and the suspension,
protected from the atmospheric humidity, is vigorously stirred
for 3 hours at room temperature. This treatment enables to eli-
minat~ almost completely the acetic acid, without 1008ing any
2,2-diacetoxyethanol. The su~pension is filtered and the preci-
pitate i8 washed ~ith a little methylene chloride. From the col-
le¢ted filtrate are removed, by evaporàtion under ~acuum in the
rotating e~aporator, together with the methylene chloride, also
the àcetoxyacetaldehyde and the acetic acid residue, The diace-
toxyethanol thereby obtained can be further purified by con~en-
~0 tional methods.