Process for synthesis of L-glutamine

A glutamine and synthesis method technology, applied in the field of synthesis of L-glutamine, can solve the problems of incomplete low-temperature reaction, difficult separation of products, high-temperature racemization of phthaloyl glutamic acid, etc., and achieve production cost Low, easy crystallization and separation, and the effect of reducing production costs

Inactive Publication Date: 2005-01-26
NANJING UNIV
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  • Claims
  • Application Information

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Problems solved by technology

[0009] Since King et al. found that there were high-temperature racemization, incomplete low-temperature reaction and difficult separation of products in the synthesis o

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037]Add 100 grams of L-glutamic acid and 60 grams of phthalic anhydride into a 500ml flask, control the temperature of the oil bath at 150±5°C, react for 45 minutes after melting, pour it into boiling water while it is hot, cool and crystallize to obtain phthaloyl -98.2 grams of L-glutamic acid (yield 87%) and 27.5 grams of L-pyroglutamic acid (yield 85%); 30 grams of phthaloyl L-glutamic acid were boiled in acetic anhydride for 15 minutes to produce Phthaloyl-L-glutamic anhydride 24.7 grams (yield 88%); 20 grams of this anhydride directly react with 25% strong ammonia water at room temperature, because the reaction is more intense, there is heat of reaction to be released, preferably slowly Add acid anhydride or start the reaction under cooling conditions, and the reaction can generally be completed within ten minutes. After distilling off ammonia, concentrating, and acidifying, 18.5 grams of phthaloyl-L-glutamine can be precipitated (87% yield) ; Dissolve 10 grams of phtha...

Embodiment 2

[0039] Add 60 grams of L-glutamic acid and 40 grams of phthalic anhydride into a 500ml flask, control the temperature of the oil bath at 150±5°C, react for 50 minutes after melting, pour it into boiling water while it is hot, cool and crystallize to obtain phthaloyl -L-glutamic acid 61.8 grams (yield 83%) and L-pyroglutamic acid 13.3 grams (yield 82%); Following steps are the same

Embodiment 3

[0041] Synthesize phthalyl-L-glutamine with the same operation steps as in Example 1, weigh 10 grams of phthalyl-L-glutamine and directly dissolve in 60 ml of water with 3% hydrazine hydrate at room temperature Place it in the mixed solution with ethanol for two days, acidify with hydrochloric acid, adjust the pH to 3, filter and remove the phthalic hydrazide precipitate, and obtain phthalic hydrazide 5.3 g (yield 90%), the clear liquid is concentrated under reduced pressure, adjusted to The pH value was 6.0, and 4.6 grams of L-glutamine crude product was crystallized, which was washed with ethanol to obtain 4.2 grams of refined product (yield 80%).

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Abstract

Disclosed is a process for synthesis of L-glutamine which consists of, reacting ortho-phthalic anhydride and excess L-glutamine at 120-180 deg. C, obtaining phthaloyl-L-glutamine and L-pyroglutamic acid, separating to obtain L-pyroglutamic acid and phthaloyl-L-glutamine, subjecting the latter and acetic anhydride to azeotropy 3-30 minutes to form phthaloyl-L-glutamic acid anhydride, acting with stronger ammonia water directly at room temperature, obtaining phthaloyl-L-glutamine, charging hydrazine hydrate solution, dispensing 48 hours to remove the protective groups.

Description

1. Technical field [0001] The invention relates to a synthesis method of L-glutamine, which belongs to the technical field of chemical synthesis. 2. Technical background [0002] L-glutamine (L-glutamine) is the most abundant free amino acid in mammalian plasma, which has many important physiological functions. Its structural formula is: NH 2 COCH 2 CH 2 CH(NH 2 )COOH. According to current literature reports, the chemical synthesis of L-glutamine mainly has the following six approaches: [0003] 1. L-glutamic acid-γ-methyl ester method of protecting amino groups with carbon disulfide. In this method, L-glutamic acid and methanol are first formed into an ester, and then carbon disulfide is added to react with the amino group to form ammonium aminodithioformate to protect the amino group, and ammonia gas is introduced until saturation, left for 4-5 days, and then concentrated under reduced pressure Remove ammonia, add glacial acetic acid to remove carbon disulfide, evapo...

Claims

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Application Information

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IPC IPC(8): C07C231/10C07C237/06
CPCY02P20/55
Inventor 焦庆才钱绍松陈然吴晓燕
Owner NANJING UNIV
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