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Патент USA US2408096

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Patented Sept. 24, 1946
2,408,095
‘UNITED STATES. PATENT OFFICE
HIGHLY USEFUL COMPOUNDS
William Jennings Peppel, Wilmington, Del., as
signor to E. I. du Pont de Nemours & Company,
Wilmington, Del.,“a corporationrof Delaware
No Drawing. Application November 11, 1943,
Serial No. 509,895
6 Claims. (01. 260-455)
1.
2
This invention relates to the alpha-halogeno
be’ta-acylthiopropionic acids and their esters.
The
alpha-halogeno-beta-acylthiopropionio
propionic acid. The acid may be puri?ed by re
crystallization from petroleum ether. It forms
white crystals melting at 75° C‘.
acids and their esters constitute a hitherto un
known class of compounds. These compounds
are of great interest in chemical syntheses be
cause of the presence of three reactive groups in
the‘same molecule. For example, they can be
If desired, a few drops of ascaridole may be
added to the initial reaction mixture, in which
‘case the reaction is even more vigorous, than
when no catalyst is employed. The yield in
alpha-chloro-beta-acetylthiopropionic
acid
is
converted to they corresponding monothiols by
substantially the same.
controlled hydrolysis of the acylthio group, or to 10
Analyses: Calculated for'CsHvOsClS! C, 32.8%;
the corresponding dithiols by simultaneous or
H, 3.8%; ‘S. 17.5%; C1, 19.5%; neutralization
stepwise replacement of both the acylthio and
equivalent, 182.5. Found: C, 32.9%; H, 4.3%; S,
halogen groups by thiol groups. They may also
17.6%; C1, 19.9%; neutralization equivalent, 189.
be converted to a variety of derivatives by ex
Instead of the free alpha-chloroacrylic acid, an
change of the halogen atom for other groups ac 15 ester thereof may be used, as shown in the fol
lowing example:
cording to known methods.
An object of this invention is the new class of
Earample II
beta-acylthiop-ropionic . acids and "their esters.
To 90 parts of methyl alpha-chloroacrylate is
Another object is to provide a general process 20 added 57 parts of thiolacetic acid. After stand
leading to these compounds in excellent yields.
ing in the sunlight for one-half hour, the mix
Other objects will appear hereinafter.
ture becomes hot, though no external cooling is
These objects are accomplished by the present
necessary. After 24 hours at room temperature ,
invention wherein a thiol carboxylic acid, e. g.,
and ordinary room illumination, the reaction
thiolacetic acid is reacted with an alpha-halo;
product is distilled at reduced pressure. There
geno-acrylic acid wherein the halogen is of
is obtained 103 parts (yield: 84% of the theory)
of pure methyl alpha-chloro-beta-acetylthiopro
atomic weight above 20, or an ester thereof,
whereby an alpha-halogeno-beta-acylthiopro
pionate, boiling at 72° C. at 1 mm. and having a
pionic acid, or an ester'thereof, is produced.
refractive index ND25=l.4898.
The products of this invention have the gen 30
Analyses.
Calculated for C6H9O3C1S2 S,
eral formula
16.3%; C1, 17.9%. Found: S, 16.6%; CI, 17.8%
The process of this invention is applicable to
any alpha-haloacrylic acid or ester wherein the
halogen is of atomic weight above 20 and to any
wherein X is halogen, R1 is a monovalent hydro
thiolcarboxylic acid wherein the radical attached
carbon radical and R2 is hydrogen or the non 35 to the thiocarboxyl group is hydrocarbon, There
hydroxyl portion of an alcohoL.
may thus, be obtained alpha-bromo-beta-acetyl
The more detailed practice of the invention is
thiopropionic acid, alpha-iodo-beta-propionyl
illustrated by the following examples, wherein
thiopropionic acid, ethyl alpha-bromo-beta
parts given are :by weight. There are, of course,
butyrylthiopropionate, propyl alpha-chloro-beta
many forms of the invention other than these 40 lauroylthiopropionate, butyl alpha-chloro-beta
organic compounds, viz., the alpha-halogeno
speci?c embodiments.
.
acetylthiopropionate,
cyclohexyl
alpha-iodo
Example I
beta-acetylthiopropionate, dodecyl alpha-bromo
beta-benz0ylthiopropionate, octadecyl alpha
To 100 parts of alpha-chloroacrylic acid is
chloro-beta-acetylthiopropionate, 'phenyl alpha
added 78 parts of thiolacetic acid. An exother
chloro-beta-propionylthiopropionate,
benzyl al
mic reactionstarts at once and, within ?ve min
pha-bromo-beta-acetylthioprop-ionate, the poly
utes, the temperature of the reaction mixture
(alpha-halogeno-beta-acetylthio) propionates of
reaches 120° C. External cooling is then applied
polyhydric
alcohols such as ethylene glycol, hexa
to prevent an excessive temperature rise. After
15 minutes, the mixture is cooled somewhat, dis 50 methylene glycol, glycerol, etc. The alcohol
esteri?ed with the alpha-halogenoacrylic acid
solved in 160 parts of hot benzene, and 115 parts
may
be aliphatic, cycloaliphatic, aromatic, alkyl
of petroleum ether are ,added. Upon cooling in
aromatic and may contain inert groups such as
ice water, the reaction product crystallizes. ‘It
alkoxy, 'aryloxy, thioether, sulfone, etc. The
is ?ltered and dried, giving 130 parts (yield: 91%
of the theory) of alpha-chloro-beta-acetylthio 55 alpha-halogenoacrylic ester may be a phenol
2,408,095
4
3
1. Process for making an alpha-halogeno-beta~
ester. 'I‘hiolacetic acid is the most available and
acetylthiopropionic compound which comprises
preferred thiolcarboxylic acid.
reacting thiolacetic acid with an alpha-halogeno
acrylic compound of the class consisting of alpha
chloroacrylic acid and its methyl ester.
The reaction of thiolcarboxylic acids with the
alpha-halogenoacrylic acids or esters proceeds in
general quite readily. If desired, it can be accel
2. Alpha-chloro-beta-acetylthiopropionic acid.
3. Methyl alpha-chloro-beta-acetylthiopropio
erated by the use of an addition-promoting cata
lyst such as ascaridole or benzoyl peroxide, or by
nate.
the use of physical agents such as heat or ultra
4. An organic compound of the class consisting
alpha-chloro-beta-acetylthiopropionic acid
and its methyl ester.
action product, according to its nature, may be
'5. Process for making alpha-chloro-beta
isolated by crystallization, ?ltration, distillation
acetylthiopropionic acid which comprises react
or any other convenient method.
ing thiolacetic acid with alpha-chloroacrylic acid.
The above description and examples are in
6. Process for making methyl alpha-chloro
tended to be illustrative only. Any modi?cation 15
beta-acetylthiopropionate which comprises react
of or variation therefrom which conforms to the
ing thiolacetic acid with methyl alpha-chloro
spirit of the invention is intended to be included
acrylate.
within the scope of the claims.
WILLIAM JENNINGS PEPPEL.
What is claimed is:
violet light.
Solvents such as benzene, toluene
or aliphatic hydrocarbons may be used. The re
10
of
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