4-CHLORO-5-OXO-HEXANOIC ACID NITRILE, 6-CHLORO-5-OXO-HEXANOIC ACID NITRILE AND PROCESS FOR THEIR MANUFACTURE

NITRILE D'ACIDE CHLORO-4 OXO-5 HEXANOIQUE ET D'ACIDE CHLORO-6 OXO-5 HEXANOIQUE

English Abstract

4-CHLORO-5-OXO-HEXANOIC ACID NITRILE,
6-CHLORO-5-OXO-HEXANOIC ACID NITRILE
AND PROCESS FOR THEIR MANUFACTURE
Abstract of the disclosure:
The compounds 4-chloro-5-oxo-hexanoic acid nitrile and
6-chloro-5-oxo-hexanoic acid nitrile are prepared by chlori-
nating 5-oxo-hexanoic acid nitrile in an aqueous 20 to 40%
solution at temperatures of from 25 to 55°C, separating the
precipitating oily second phase and submitting it to distil-
lation. Said compounds are valuable starting products for
preparing ?- or .epsilon. -amino acids and important synthesis pro-
ducts for preparing heterocyclic compounds.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. 5-Oxo-hexanoic acid nitriles selected from the group
consisting of 4-chloro-5-oxo-hexanoic acid nitrile of the form-
ula

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and 6-chloro-5-oxo-hexanoic acid nitrile of the formula

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2. 4-Chloro-5-oxo-hexanoic acid nitrile of the formula

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3. 6-Chloro-5-oxo-hexanoic acid nitrile of the formula

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4. A process for preparing the compounds claimed in
claim 1, in which 5-oxo-hexanoic acid nitrile is reacted with
chlorine in an aqueous 20 to 40% solution of the acid nitrile
at a temperature of from 25 to 55°C.

5. A process as claimed in claim 4 for preparing 4-chloro-


5-oxo-hexanoic acid nitrile, in which the oily second phase
precipitated during the reaction is separated and distilled
to isolate 4-chloro-5-oxo-hexanoic acid.

6. A process as claimed in claim 4 for preparing 6-
chloro-5-oxo-hexanoic acid nitrile, in which the oily second
phase precipitated during the reaction is separated and distil-
led to isolate 6-chloro-5-oxo-hexanoic acid nitrile.

Description

15~48S~O
The pre~ent invention relates to 4-chloro-5-oxo-he~anoic
acid nitrile of the ~ormula
CH3 - C - CH - CH~ - CHz - CN
Il I '
0 Cl
and 6-chloro-5-oxo-hexanoic acid nitrile of the formula
CH2 - C -- CH2 - CH2 CH2
.. . I I .
Cl 0
which have not yet been described in literature.
The present invention further relateo to a process for
preparing a mixture of 4-chloro-5-oxo-hexanoic acid nitrile
and 6-chloro-5-oxo-hexanoic acid nitrile, which comprises
chlorinating 5-oxo-hexanoic acid nitrile in a~ aqueous 20 to
4~ solution at temperaturesof from 25 to 55C.
- The hydrogen chloride liberated in the chlorination is
absorbed by water. It is however surprising that the nitrile
; group is not hydrolyzed in the process according to the in-
~ention, although such a reaction had to be expected in the
Z0 aqueous medium containing hydrochloric acid.
~he trifunctional compounds 4-chloro- and 6-chloro-5-oxo-
hexanoic acid nitrile accessible by the present invention are
valuable starting products for preparing ~ - or -amino acids
and~being ~ -chloroketonestmoreover important synthesis com-
ponents for preparing heterocyclic compounds.
The following method has proved especia1ly successful
for the chlorination process according to the inventions
The starting phase of the chlorination i~ preferably
29 effected at temperatures of from 25 to 40C. When the reac-

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. .
1048540
tion is in full course and the originally green-yellow
colored solution has decolored, chlorination i8 continued
at temperatures of from 40 to 55C, preferably of from 40
to 45C. Exterior cooling is generally recommended for main-
taining this temperature level. The chlorine quantity reac-
~ing in this main reaction phase is about 2 to 3 times the
chlorine quantity reacting ~n the starting phase of the chlori-
nation. The terminal phase of the chlorination is indicated
by a diminution of the chlorine absDrption and by the yellow
coloring of the reaction solution to be observed anew. The
opacity of the solution wh$ch already occurs in the starting
phase indicates the precipitation of the water insoluble
chlorination products. Further chlorination of theses products
i9 prevented by said precipitation.
The two chloro-keto-nitriles prepared by the process
according to the invention may be isolated in quite simple
manner. When terminating the chlorination the precipitating
organic bottom phase is separated, washed with water and
distilled without intermediate drying. Both components may
be readily separated owing to the fact that there is an inter-
val of 30 C between their boiling points.
The following example illustrate the invention.
E X A M P L_E s
A solution of 333 g (3 moles) of 5 oxo-hexanoic acid
nitrile in 1332 ml of water was introduced into a 2 liter
flask and gaseous chlorine was added while stirring at a tem-
perature of from 40 to 42 C, -until the stoichiometrically
required chlorine quantity had been absorbed.
29 After terminating the chlorine absorption stirring was



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continued for 1 hour, the organic phase wa~ separated and
wa~hed twice with 400 ml of water each time.
m e reaction product was then distilled over a vacuum
. ~acket column(length 100 cm, diameter 25 mm)-charged with
; 5 Raschig rings (di~meter 4 mm) and a quantity of 205 g of
4-chloro-5-o~o-hexanoic acid nitrile corresponding to a yield
of 47.3% of the theory wa~ isolated at a boiling point
of 90C (1 mm Hg) and a quantity of 95 g of 6-chloro-5-oxo-
. hexanoic acid nitrile corresponding to a yield Or 21.5% of
tO the theory at a boiling point of 118C (1 ~ m Hg) .
Both new compounds are cle~r liquid~ Or a density of 1.i5.

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