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Preparation method of D-p-hydroxyphenylglycine methyl ester

A technology of p-hydroxyphenylglycine methyl ester and p-hydroxyphenylglycine, which is applied in the field of organic chemical synthesis, can solve the problems of strong volatility of hydrogen chloride, unstable intermediate process control, large fluctuation, etc., so as to avoid difficult handling and ensure yield. Effect

Pending Publication Date: 2020-05-15
SHANXI WEIQIDA PHARMA IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented process allows for easy production with high yields and purity levels of d-(-)-Phenylacetic acid (DOPA) without producing harmful chemical substances like HCl or Thionyl Chlorides during synthesis. It also simplifies the manufacturing processes while maintaining good overall performance over time.

Problems solved by technology

Technological Problem addressed in this patents relate to improving the efficient manufacturing processes involved in producing various types of chemical compounds such as deoxynilase inhibitors or pantothenidonins. Previous attempts have resulted in low yields and safety concerns associated with these intermediary products. To address those issues, new techniques involving alternative solvent systems were developed.

Method used

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  • Preparation method of D-p-hydroxyphenylglycine methyl ester
  • Preparation method of D-p-hydroxyphenylglycine methyl ester
  • Preparation method of D-p-hydroxyphenylglycine methyl ester

Examples

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Embodiment 1

[0026] (1) Esterification step

[0027] In the reaction bottle of 500mL, add 200mL methanol, 100g D-hydroxyphenylglycine (HPG) and the 98wt% concentrated sulfuric acid of 75g, carry out esterification reaction 2 hours under reflux; Then slowly vacuumize, make the vacuum in the reaction bottle about- 0.075MPa~-0.082MPa, temperature about 80°C, collect distillate methanol and water;

[0028] Then release the vacuum, add 170mL of methanol into the reaction bottle, and carry out the esterification reaction under reflux for 2 hours; then slowly vacuumize the reaction bottle so that the vacuum in the reaction bottle is about -0.075MPa~-0.082MPa, and the temperature is about 80°C. Collect the distillate methanol and water;

[0029] Repeat the above steps of adding 170mL of methanol, esterifying for 2 hours, and distilling out methanol and water under reduced pressure;

[0030] Detected by high performance liquid chromatography (PHLC), the yield of the finally obtained D-p-hydroxyph...

Embodiment 2

[0039] Embodiment 2 (pilot scale scale-up experiment)

[0040] (1) Esterification step

[0041] Add 12L methyl alcohol, 6kg D-p-hydroxyphenylglycine (HPG) and the 98wt% vitriol oil of 4.5kg in the reaction flask of 30L, carry out esterification reaction 2 hours under reflux; Slowly vacuumize then, make the vacuum in the reaction flask about -0.075MPa~-0.082MPa, the temperature is about 80°C, collect distillate methanol and water;

[0042]Then release the vacuum, add 10.2L methanol to the reaction bottle, and carry out the esterification reaction under reflux for 2 hours; then slowly vacuumize the reaction bottle so that the vacuum in the reaction bottle is about -0.075MPa~-0.082MPa, and the temperature is about 80°C. Methanol and water;

[0043] Repeat the steps of adding 10.2L methanol, esterifying for 2 hours, and distilling methanol and water under reduced pressure;

[0044] Detected by high performance liquid chromatography (PHLC), the yield of the finally obtained D-p-...

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Abstract

The invention relates to a preparation method of D-p-hydroxyphenylglycine methyl ester. The preparation method comprises the following steps: (1) esterifying: carrying out an esterification reaction on D-p-hydroxyphenylglycine and methanol to obtain D-p-hydroxyphenylglycine methyl ester sulfate, and distilling off methanol and water under reduced pressure, wherein the D-p-hydroxyphenylglycine is added one time, and the methanol is added in batches; and (2) crystallizing the D-p-hydroxyphenylglycine methyl ester. The preparation method can very easily control the reaction endpoint, so that theyield and the quality index of the finished product can be guaranteed to the maximum extent; the preparation method provided by the invention avoids the problems of safety and operation caused by hydrogen chloride gas or thionyl chloride; and in the step of D-p-hydroxyphenylglycine methyl ester crystallization, an alkali metal hydroxide is used for adjusting the pH value of the system without using ammonia water, so that the problem that ammonia ions are difficult to treat is avoided.

Description

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Claims

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Application Information

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Owner SHANXI WEIQIDA PHARMA IND
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