JPS6036440B2 - Production method of pyroglutamylglycine - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing pyroglutamylglycine.

Pyroglutamylglycine is supplied as a precursor of bioactive peptides such as gastrin (J. Chem. So
c. C. 1967.2410) In addition, since it is a substance that itself has antibacterial properties, heat retention properties, etc., it has uses such as cosmetics.

When glutamic acid (or pyroglutamic acid) and glycine are mixed and heated at a temperature near the melting point of pyroglutamic acid, glycine quickly dissolves, producing dipeptide, tribeptide, tetrabeptide, etc., and the proportion of glycine in the raw material increases. It is known that when the reaction time is too long, a water-insoluble polymeric polypeptide is produced.

At this time, in order to prevent the by-product of tribeptide and tetrabeptide, it is possible to reduce the proportion of glycine used or to shorten the reaction time, but in that case, the conversion rate and yield may drop significantly, or the reaction time may be reduced. This has the disadvantage that it takes a considerable amount of time, and in any case, it cannot be used as a means for selectively producing pyroglutamylglycine. The present inventors conducted the thermal condensation of glutamic acid (or pyroglutamic acid) and glycine in the presence of acetophenone, thereby suppressing the by-products of higher peptides such as dipeptide and tribeptide, and suppressing the by-product of higher peptides such as dipeptide and tribeptide. It has been found that glutamylglycine can be selectively produced.

The present invention is based on this knowledge. Since the glutamic acid used as a raw material in the method of the present invention is easily converted into pyroglutamic acid by heating, the same result will be obtained no matter which one is used.

In the method of the present invention, the raw materials glutamic acid and glycine are preferably used in stoichiometric amounts, but glycine may be used in slightly excess to improve the conversion rate.

Usually, it is appropriate to carry out the reaction in a range of 1:1 to 1:5 (molar ratio). Acetophenone is at least 5% by weight of the raw material
It is preferable to use it in a moderate amount.

Even when used in a large amount, it does not adversely affect the reaction itself, so it may also be used as a solvent if necessary. The reaction time is usually 130 to 200 qC, and the reaction time is 10 to 6 minutes (preferably 3 minutes or less). The reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or carbon dioxide.

The water vapor generated during the reaction can be removed continuously, but this is not a practical requirement. Pyroglutamylglycine obtained by the method of the present invention can be easily separated from created substances and unreacted amino acids by making it into an aqueous solution and passing it through an ion exchange resin.

Dibef with a simple structure such as pyroglutamylglycine.

Although even tide must be produced through expensive and complicated steps using existing synthesis methods, the method of the present invention can be produced with extremely high selective production rates through simple operations as described above. This method has extremely high practical value because it can produce pyroglutamylglycine. The present invention will be explained below with reference to Examples and Comparative Examples.

Example 1 Glutamic acid and glycine were mixed at a molar ratio of 1:1, placed in a glass reaction tube purged with carbon dioxide gas, and after adding 1% by weight of acetophenone, the glass tube was sealed.

When this glass sealed tube was reacted for 1,750,030 minutes in an oil bath, the conversion rate of glutamic acid was 40.4%.
The selectivity for pyroglutamylglycine was 78%. In addition, the production rate of pyroglutamylglycylglycine is 2.
The production rate of pyroglutamylglycylglycylglycine was 0.6%, and the production of glycine-only peptides and glycine cyclic dimers was negligible. Comparative Example 1 ■ When glutamic acid and glycine were mixed in a 1:1 molar ratio and the same reaction as above was carried out without adding acetophenone, the selectivity for pyroglutamyl glutamine was 64.
%Met.

The yields of pyroglutamylglycylglycine and pyroglutamylglycylglycylglycine were 4.6% and 2.
5%, and an increase in by-products of glycine-only peptides and diketopiverazine was observed. ■ Mix glutamic acid and glycine in a 1:1 molar ratio and raise the reaction temperature to 90℃.
When the reaction was carried out at a lower temperature, it took 10 hours to reach a yield of pyroglutamylglycine of 10% and a selectivity of 80%.

Example 2 Glutamic acid and glycine were mixed at a molar ratio of 1:1.5, a significant percentage of acetophenone was added, and the reaction was carried out for 3 times at 175°C in exactly the same manner as in Example 1, resulting in pyroglutamylglycine. The selectivity was 77%.

In addition, the yield was 2.4% of pyroglutamylglycylglycine and 0.7% of pyroglutamylglycylglycylglycine. (Conversion rate of glutamic acid 45%) Comparative example 2 ■ When the same reaction as above was carried out without adding acetophenone, the selectivity of pyroglutamylglycine was 55%.
The yield of pyroglutamylglycylglycine is 6.9%, and the yield of pyroglutamylglycylglycylglycine is 3.6%.
%.

In this reaction, the effect of adding 4-methylacetophenone and propiophenone was also tried, but no change in yield or selectivity was observed. ■ When the same reaction was carried out with the molar ratio of glutamic acid and glycine changed to 4:1, the selectivity of pyroglutamylglycine was 80%.
However, the conversion rate (glutamic acid) was only 17%.

*Analysis of reaction products was performed using high performance liquid chromatography using a Shodex Ionpac C-811 column as a 0.1% aqueous solution of 3P04.

Claims (1)

[Claims] 1. A method for producing pyroglutamylglycine, which comprises heating glutamic acid or pyroglutamic acid and glycine in the presence of acetophenone.