DE1239697B - Process for the preparation of methionine methylsulfonium chloride or bromide - Google Patents

Description

GERMAN WTTWl PATENT OFFICE

EDITORIAL

German class: 12 q- 6/01

Number: 1239 697

File number: D 40932 IV b / 12 q

1 239 697 Filing date: February 20, 1963

Open date: May 3, 1967

It is known that methionine methylsulfonium chloride can be prepared by first adding methionine Reacts with dimethyl sulfate in concentrated sulfuric acid and the resulting methionine methyl sulfonium sulfate then allowed to react with barium chloride. This method has the disadvantage that one in large Quantities of concentrated sulfuric acid required. The removal of the sulfuric acid and the work-up of the reaction mixture is cumbersome and difficult because large amounts of sulfuric acid, as Barium sulfate are precipitated must be separated. To carry out the implementation you need enamelled vessels.

It has now been found that methionine methylsulfonium chloride or bromide can be obtained in a simple manner Way can be prepared by methionine with methyl chloride or bromide in the presence of a Reacts solvent at 20 to 60 ° C under pressure.

It has also been found that it is best to use an excess of methyl chloride or bromide is working. Yields of up to 90% are obtained if the reaction is carried out with an excess of 50% of the theoretical amount carried out.

Water has proven particularly useful as a solvent.

If the specified working temperatures are not reached or exceeded, the yield decreases. at At higher temperatures, saponification of the methyl halide takes place, at lower temperatures the implementation is not complete. The best yields are obtained when looking at the manufacture of methionine methyl sulfonium chloride at a temperature of 50 to 60 ° C, in the manufacture of Methionine methyl sulfonium bromide works at a temperature of 15 to 40 ° C.

example 1

298 g of DL methionine are suspended in 2000 ml of water in a pressure-resistant agitator vessel made of V 4 A steel with a capacity of 3 liters. 151.5 g of methyl chloride are then pressed into the vessel. The mixture is heated to 50 to 55 ° C. while stirring and is kept at this temperature for 8 hours. The pressure rises to 12 to 13 atmospheres. After cooling to 15 to 20 ° C., the excess methyl chloride is allowed to escape and the clear, pale yellow solution is treated with 0.2% activated carbon. It is then filtered and the water is evaporated in vacuo at 45 to 55 ° C. The almost colorless syrup that remains is poured into 21% methanol with stirring, methionine methylsulfonium chloride precipitating in crystalline form. It is left at -5 to for 12 hours. Process for the preparation of
Methionine methyl sulfonium chloride or bromide

Applicant:

German gold and silver refinery
formerly Roessler, Frankfurt / M., Weißfrauenstr. 9

Named as inventor:

Dr. Hans Wagner, Constance

-10 ° C and separates the precipitated crystals from the mother liquor by filtering.

340 g of methionine methylsulfonium chloride corresponding to 85.3% of theory are obtained. The end product has a purity of 99.5%. No contamination can be detected by thin layer chromatography can be detected by amino acids.

Example 2

2.98 kg of DL methionine are suspended in 151 ice water in a pressure-tight agitator vessel made of V 4 A steel with a capacity of 301. 2.85 kg of methyl bromide are then injected into the vessel. The mixture is stirred for 3 to 4 hours at 35 ° C., the methionine going into solution with formation of the ternary compound. This results in a pressure of 3 to 4 atmospheres. After cooling and draining off the excess methyl bromide, the solution is treated with 50 g of activated charcoal, filtered and evaporated at 45 ° C. in a vacuum. When no more water passes over, the syrupy residue is stirred into methanol and the mixture is left to stand at 0 to -IO ⁰ C for 9 hours. The crystals are then spun off, rewashed with 2.5 l of methanol and dried in vacuo at 70.degree

4280 g of methionine methylsulfonium bromide are obtained, which corresponds to a yield of 88% Theory corresponds. The final product has a purity of 99.5%. By thin layer chromatography no contamination by amino acids can be detected.

Claims (1)

Patent claims: 1. A process for the preparation of Methioninmethylsulfoniumchlorid or bromide, thereby characterized in that one methionine with methyl chloride or bromide in the presence of a Reacts solvent at 20 to 60 ° C under pressure. 709 578/323