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Synthetic method of dimethyl cysteamine hydrochloride

A technology of dimethylcysteine ​​hydrochloride and a synthetic method, which is applied in the directions of thiol preparation, organic chemistry, etc., can solve the problems of low product yield, complicated operation, toxicity and the like, and achieves high product yield and high operation Simple, low-cost effects

Active Publication Date: 2016-03-02
SULI PHARMA TECH JIANGYIN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The operation is complicated, and phenylhydrazine needs to be used in the third step reaction process, which is toxic, not environmentally friendly, and the yield of the product obtained is low

Method used

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  • Synthetic method of dimethyl cysteamine hydrochloride
  • Synthetic method of dimethyl cysteamine hydrochloride
  • Synthetic method of dimethyl cysteamine hydrochloride

Examples

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preparation example Construction

[0025] The method for synthesizing dimethylcysteine ​​hydrochloride involved in the present invention is characterized in that the method uses isobutyraldehyde as a starting material and is prepared through condensation, reduction and ring-opening reactions. The method comprises the following process steps:

[0026] Step 1. Condensation

[0027] Add sulfur powder and triethylamine to isobutyraldehyde, raise the temperature to 60~65°C, feed ammonia gas, keep reflux and separate water, when the temperature of the reaction solution rises to 125~130°C, the reaction will generate 5,5-di Methyl-2-isopropylthiazoline, after the reaction, the system was distilled under reduced pressure to collect 5,5-dimethyl-2-isopropylthiazoline fractions. The molar ratio of isobutyraldehyde, elemental sulfur, triethylamine and ammonia is 2:1:0.1:1.5-2.5.

[0028] Its reaction formula is:

[0029]

[0030] Step 2. Restoration

[0031] Add 5,5-dimethyl-2-isopropylthiazoline into organic solven...

Embodiment 1

[0043] Step 1. Condensation

[0044] Add 1.11kg of sulfur powder and 347g of triethylamine into 5kg of isobutyraldehyde, heat up to 60~65°C, feed ammonia gas, keep reflux and divide water, when the temperature of the reaction solution rises to 125~130°C, the reaction produces 5 , 5-dimethyl-2-isopropylthiazoline, after the reaction, the system was distilled under reduced pressure to collect 5,5-dimethyl-2-isopropylthiazoline fractions. 4.28 kg of 5,5-dimethyl-2-isopropylthiazoline was obtained with a gas phase purity of 96.7% and a yield of 78.5%.

[0045] Step 2. Restoration

[0046] Add 4kg of 5,5-dimethyl-2-isopropylthiazoline into 16kg of methanol, cool down to -5°C, add 24kg of 6N hydrochloric acid at -5-0°C, add sodium borohydride solution dropwise at -5-0°C After dropping, react at -5-0°C for 1h, reduce 5,5-dimethyl-2-isopropylthiazoline to generate 5,5-dimethyl-2-isopropylthiazolidine, add formaldehyde to the system after reaction base tert-butyl ether, sodium hydro...

Embodiment 2

[0051] Step 1. Condensation

[0052] Same as example 1.

[0053] Step 2. Restoration

[0054] Add 4kg of 5,5-dimethyl-2-isopropylthiazoline into 16kg of methanol, cool down to -5°C, add 24kg of 6N hydrochloric acid at -5-0°C, add sodium borohydride solution dropwise at -5-0°C , after dropping, react at -5-0°C for 1h, reduce 5,5-dimethyl-2-isopropylthiazoline to generate 5,5-dimethyl-2-isopropylthiazolidine, add acetic acid to the system after reaction Ethyl ester and sodium hydroxide to adjust the pH value to 7~8, separate the liquid, discard the aqueous phase, add water and hydrochloric acid to the organic phase to adjust the pH value to 2~3, separate the liquid, discard the organic phase, and the aqueous layer contains 5,5-dimethyl -2-Isopropylthiazolidine cast directly to the next step.

[0055] Step 3, open loop

[0056] The water layer containing 5,5-dimethyl-2-isopropylthiazolidine is heated to reflux, and the water and the isobutyraldehyde formed by the reaction are d...

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Abstract

The invention relates to a synthetic method of dimethyl cysteamine hydrochloride, and belongs to the technical field of organic synthesis. The method comprises the following processing steps: synthesizing 5,5-dimethyl-2-isopropyl thiazoline by taking isobutylaldehyde, element sulfur, ammonia gas and triethylamine as raw materials; reducing the 5,5-dimethyl-2-isopropyl thiazoline into 5,5-dimethyl-2-isopropyl thiazolidine under the actions of sodium borohydride and acid; and reacting the 5,5-dimethyl-2-isopropyl thiazolidine with a hydrochloric acid solution under nitrogen production to obtain the dimethyl cysteamine hydrochloride. The synthetic method has the advantages that the reaction raw materials are easily obtained; the reaction process is simple in operation; the requirement for reaction equipment is low; the reaction conditions are relatively mild; and the yield and content are high, and the content of the finally obtained dimethyl cysteamine hydrochloride is greater than 99%.

Description

technical field [0001] The invention relates to a synthesis method of dimethylcysteine ​​hydrochloride, which belongs to the technical field of organic synthesis. Background technique [0002] Dimethylcysteine ​​hydrochloride is an important intermediate of warnemulin hydrochloride. Warnemulin hydrochloride is a new generation of pleuromutilin semi-synthetic antibiotics. It belongs to diterpenes and belongs to the same genus as tiamulin. Class of drugs, antibiotics for animals. It is mainly used to prevent and treat mycoplasma disease and Gram-positive bacterial infection in pigs, cattle, sheep and poultry. It has the characteristics of broad antibacterial spectrum, strong antibacterial activity, excellent pharmacokinetic characteristics, low residue and high safety. [0003] Its preparation method is reported in the literature at present, specifically as follows: [0004] The synthetic method reported in patent 201110356445 is divided into three steps: [0005] (1) Syn...

Claims

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Application Information

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IPC IPC(8): C07C323/58C07C319/02
Inventor 乔海艳汪静莉高桂祥
Owner SULI PHARMA TECH JIANGYIN
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