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Report on D-Pyroglutamic acid
Apr 03, 2018



Report on D-Pyroglutamic acid


 L pyroglutamic acid has been reported in China, and it is a material that is constantly being developed for new uses.

In recent years, there have been studies on the chiral starting material of L - pyroglutamic acid as a synthetic amino acid and other photoactive compounds. There are few reports on D - pyroglutamic acid. 

How D-Pyroglutamic acid forms?


After high temperature treatment, glutamic acid dehydrated and transformed into cyclic pyroglutamic acid. Because of the asymmetry of carbon atoms in glutamic acid, pyroglutamic acid also has L- type and D- type, which means L- pyroglutamic acid and D- pyroglutamic acid.


Method of making D-Pyroglutamic acid

Step 1  L glutamic acid was used as the starting material to prepare D glutamic acid. Specific operation is as followings: Add L glutamic acid into the beaker, stir it and heat it up. When the temperature reaches 130 degrees, the glutamic acid gradually melts and start the dehydration cyclization. When the temperature rises to 150 to 160 degrees centigrade, continue to heat, the temperature is not too high until it dehydrated. Then the temperature rises quickly to 190 degrees centigrade.

After holding for 1 h, heat and pour into cold water, get DL pyroglutamic acid, heat up hydrolysis with 2 mol/L hydrochloric acid, then get DL-a glutamic acid.

Step 2  D glutamic acid can be obtained by the separation by preferential crystallization. 

 Specific operation is as followings: The specific rotation is -32° -31° after purification. Then the glutamic acid is heated and coking. The temperature should be controlled at 150 ±5  degrees centigrade and three times. Be careful to feed into the Ling water, decolorizing and refining with activated carbon, and then D- pyroglutamic acid is got.
















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