Process for preparing sulfonyl halides

Details Process for preparing sulfonyl halides Process for preparing sulfonyl halides

1999-08-25

2001-09-18

Killos, Paul J. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Sulfur halides

Reexamination Certificate

active

06291710

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for preparing compounds of the general formula (I)
in which
n=1 to 18,
R
1
, R
2
, independently, represent H, F, Cl, Br, (C
1
-C
8
)-alkyl, (C
1
-C
8
)-alkoxy, (C
2
-C
8
)-alkoxyalkyl, (C
3
-C
8
)-cycloalkyl, (C
6
-C
18
)-aryl, (C
7
-C
19
)-aralkyl, (C
3
-C
18
)-heteroaryl, (C
4
-C
19
)-heteroaralkyl, (C
1
-C
8
)-alkyl-(C
6
-C
18
)-aryl, (C
1
-C
8
)-alkyl- (C
6
-C
18
)-heteroaryl, (C
1
-C
8
)-alkyl-(C
3
-C
8
)-cycloalkyl or (C
3
-C
8
)-cycloalkyl-(C
1
-C
8
)-alkyl group, or R
1
and R
2
are linked via a (C
3
-C
7
)-carbocyclic compound for the same values of n,
with the proviso that R
1
and R
2
may each be regarded per se as representing different substituents,
R
3
represents H, Cl, Br, I or R
1
,
Hal represents Cl or Br,
from compounds of the general formula (II)
in which
n, R
1
, R
2
, R
3
and Hal are defined in the same way as set forth above, and sulfite salts with subsequent halogenation. The invention also provides use of compounds of the general formula (I).
Compounds of the general formula (I) are important substrates for the synthesis of bioactive substances such as, for example, the fungicide Methasulfocarb® (CAS-No.: 66952-49-6).
BACKGROUND OF THE INVENTION
DE 1200809 describes two ways to prepare chloromethanesulfonic acid chloride. Both use s-trithian as starting material and produce yields of only 51.6% and 61.7%. In addition, the relatively expensive starting material, s-trithian is also required to prepare the desired derivatives. Also, pure products are not obtained by this process. Rather, mixtures of mono- and polychloroalkylsulfonic acid chlorides are produced, which are difficult to separate completely. Also a number of sulfur-containing side products are produced, the waste disposal of which can cause problems.
DE-OS 2545644 discloses a process by which R-Hal compounds are reacted with sulfite salts by phase transfer catalysis in water to give salts of sulfonic acids. In a separate second step, after isolation and drying, the sulfonic acid salts obtained are converted into the corresponding sulfonic acid chlorides by means of a chlorinating agent. Yields of 69% are achieved. In this process, production of the sulfonic acid and chlorination are separated by a drying stage. The disadvantage is that the salt mixture which is used for chlorination has to be extremely dry (s. Organikum 1986, 16th edition VEB, bottom cf p. 422), since residues of the aqueous solvent from the first step lead to a higher consumption of the chlorinating agent and to an increase in the range of secondary products.
This extreme drying of salt mixtures, however, is very difficult to achieve in an industrial process and leads to a time-consuming, cost-intensive drying procedure. Also, the handling of solids is an obstacle to industrial use of the process.
SUMMARY OF THE INVENTION
The object of the invention, therefore, was to provide a process which enabled the preparation of sulfonic acid halides in improved yields while avoiding intermediate isolation and drying of the sulfonic acid salts.
Accordingly compounds of the general formula (I)
in which
n=1 to 18,
R
1
, R
2
, independently, represent, H, F, Cl, Br, (C
1
-C
8
)-alkyl, (C
1
-C
8
)-alkoxy, (C
2
-C
8
)-alkoxyalkyl, (C
3
-C
8
)-cycloalkyl, (C
6
-C
18
)-aryl, (C
7
-C
19
)-aralkyl, (C
3
-C
18
)-heteroaryl, (C
4
-C
19
)-heteroaralkyl, (C
1
-C
8
)-alkyl-(C
6
-C
18
)-aryl, (C
1
-C
8
)-alkyl-(C
6
-C
18
)-heteroaryl, (C
1
-C
8
)-alkyl-(C
3
-C
8
)-cycloalkyl or (C
3
-C
8
)-cycloalkyl-(C
1
-C
8
)-alkyl group, or R
1
and R
2
are linked via a (C
3
-C
7
)-carbocyclic compound for the same values cf n,
with the proviso that R
1
and R
2
may each be regarded per se as representing different substituents,
R
3
represents H, Cl, Br, I or R
1
,
Hal represents Cl or Br,
are prepared from compounds of the general formula (II)
in which
n, R
1
, R
2
, R
3
and Hal are defined in the way given above,
and sulfite salts with subsequent halogenation, wherein subsequent halogenation is performed in an organic solvent which is fully or partly miscible with water, so that high purity compounds of the desired type are obtained in very good yields, dissolved in the organic solvent but, without intermediate isolation of a solid, apart from the salts.
In the context of the invention, compounds where n=1, R
1
, R
2
=H , Hal=Cl and R
3
=H, Cl, Br, I or R
1
are preferred. A compound in which n=1, R
1
, R
2
=H, Hal=Cl and R
3
=Cl is particularly preferably prepared by the process according to the invention.
Reaction of the sulfite salt with the compound of the general formula II, in which n, R
1
, R
2
, R
3
and Hal may be defined in the same way as above, is preferably performed in water as solvent. Optionally, water-miscible organic solvents such as, for example, alcohols such as methanol or ethanol etc., or ethers such as tetrahydrofuran (THF) or dioxan, or ketones such as acetone, may also be admixed with the water. Phase transfer catalysis, as described in DE 2545644, may also be suitable here.
In principle any organic solvent which is either fully or partly miscible with water and is familiar to a person skilled in the art is suitable as long as it enables the water to be removed from the reaction mixture. Ternary mixtures with water as one component are also suitable for this purpose. However, the use of ethers during subsequent halogenation is preferred. Particularly preferred ethers which may be mentioned are diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether or tetraethylene glycol diethyl ether.
Any salts familiar to a person skilled in the art and known to be used for this purpose are suitable as sulfite salts (Houben-Weyl, Methoden der Organischen Chemie vol. 9, p. 347 et seq. or E11, p. 1055). However, the use of alkali metal or alkaline earth metal sulfite salts or ammonium sulfite salts and their hydrogen sulfite salts is preferred. Sodium sulfite is particularly preferably used.
A number of halogenating agents which can be used are described in Houben-Weyl (Methoden der organischen Chemie E11, p. 1071 et seq. or VIII p. 347 et seq.). The following may preferably be used: thionyl chloride, phosphorus pentachloride, phosphorus trichloride, phosphorus oxychloride, oxalyl chloride. However, the use of phosgene as halogenating agent is particularly preferred.
As described above, preparation of the sulfonic acid salt is preferably performed in aqueous media. The temperature during reaction may vary between 20° and 200° C., preferably between 40° and 150° C. The reaction is preferably performed in a sealed vessel. The pressure, which may be adjusted during reaction, is generally between 1 and 100 bar, preferably 3 to 15 bar.
Subsequent halogenation may be performed at a temperature of 0° to 150° C., preferably 50° to 100° C.
A catalyst is preferably used when halogenating with phosgene. These types of catalysts are, inter alia, N-alkylactams, such as N-methylpyrrolidone, and the compounds mentioned in DE 2743542 and the references cited there. The use of DMF for this purpose is particularly preferred.
The invention also provides use of the compounds of the general formula (I) prepared by the process in claim
1
in syntheses for preparing bioactive substances.
The reaction of sulfite salts with organic halides is particularly preferably performed in water as solvent. In this case, e.g. sodium sulfide is dissolved in water and optionally an alcohol or acetone (phase-facilitator) and e.g. a haloalkane such as methylene chloride are added. The use of a phase-facilitator during reaction, however, is not absolutely necessary. The reaction proceeds without any problems with a yield of 88 to 91%.
As indicated above, subsequent halogenation, for example chlorination, has to be performed under anhydrous conditions. A number of possibilities are available to a person skilled in the art. Inter ali

Affiliated with

Also associated with

Rating

Process for preparing sulfonyl halides does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for preparing sulfonyl halides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing sulfonyl halides will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2453464