JPS6248656A - N-fumaryl-l-phenylalanine methyl ester and production thereof - Google Patents

Abstract

NEW MATERIAL:N-fumaryl-L-phenylalanine methyl ester of formula. USE:Useful as an intermediate raw material for aspartame. Aspartame can be produced from the titled compound in high yield at a low cost. PREPARATION:The compound of formula (trans-isomer) can be produced by reacting fumaric acid with phenylalanine methyl ester in an aprotic polar solvent such as dimethylformamide in the presence of a conventinal condensation agent (e.g. N,N'-cicyclohexyl-carbodiimide) at room temperature for <=1hr. The molar amount of fumaric acid is preferably excess to the phenylalanine methyl ester.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application N-fumaryl-phenylalanine methyl ester (hereinafter abbreviated as FPM) represented by the following formula is a new compound.

The compound according to the present invention is suitable for the production of aspartic acid using fumaric acid as a raw material (see JP-A-57-138383) and the production of phenylalanine using cinnamic acid as a raw material (see JP-A-56-26197). It is useful as a raw material for the production of aspartame by a reaction similar to the known ammonia addition reaction using microorganisms or by a synthetic chemical ammonia addition reaction. FPM is a very useful substance because the production of aspartame using FPM as a raw material can be expected to be a process for producing aspartame at a lower cost than conventional methods. According to the present invention, this FPM can be produced in high yield, which is very important from the above point of view.

Problems to be Solved by the Prior Art and the Invention There are no reports on the FPM and its manufacturing method in the prior art. For example, it has been reported that dicarboxylic acid anhydride can be obtained by condensing maleic acid in the cis form with L-phenylalanine methyl ester (Japanese Patent Laid-Open No. 48-527
41), but this reaction does not proceed if 1-lance fumaric acid is used. Therefore, when the present inventors used fumaryl dichloride as a raw material and reacted it with L-phenylalanine methyl ester in dioxane using a base such as pyridine, only a rhinoceros brown solid precipitate was obtained. FPM was not obtained. Next, when the mixture was refluxed in dioxane in the absence of a base, generation of hydrogen chloride was observed, but no fumaric acid derivative was obtained, and only an isomerized maleic acid derivative was obtained.

As mentioned above, the acid anhydride method or acid chloride method
It has become clear that PM is extremely difficult to produce. Then, when fumaric acid and L-phenylalanine methyl ester were reacted in a methanol-based or methanol/water solvent using a common dehydrating reagent,
The desired FPM was obtained, although in an extremely small amount. However, since this method cannot be put into practical use, the inventors continued their research and developed the desired FPM.
was successfully produced in high yield.

Means for Solving the Problem According to the present invention, FP, which is a new substance represented by the above formula,
Furthermore, in the present invention, a hydrogen-free polar solvent is used as a reaction solvent, and in this system, fumaric acid and phenylalanine methyl ester are reacted using a common dehydrating reagent to obtain the desired FPM (lance isomer). can be produced in high yield.

Function As described above, according to the present invention, the reaction is carried out using a hydrogen-free polar solvent [for example, dimethylformamide (hereinafter abbreviated as DMF),
dioxane, tetrahydrofuran, methylene chloride, pyridine, etc.] in a conventional condensing agent [for example, N,N'-dicyclohexylcarbodiimide (hereinafter 1) abbreviated as CC).
, ethyl chloroformate (hereinafter abbreviated as CIC0OEt), diethyl phosphate cyanide (hereinafter abbreviated as DEPC)], etc., and react fumaric acid with, for example, the hydrochloride of L-phenylalanine methyl ester to obtain the desired FP.
M (1-lance isomer) can be obtained in high yield. There are no particular limitations on the reaction temperature or reaction time for this reaction, but room temperature is sufficient for the reaction temperature, and the reaction time is at most 1.
Time is enough. After the reaction is completed, a conventional post-treatment (for example, extraction with methylene chloride-saturated NaHCO3 water, acidification of the aqueous layer with 2N-HC7!, and extraction with methylene chloride) is performed, followed by an appropriate treatment. High purity FPM can be crystallized and recovered by recrystallization from a solvent.

Although the reaction molar ratio of fumaric acid and phenylalanine methyl ester is generally a reaction stoichiometric ratio, it is actually desirable to have an excess of fumaric acid.

N-fumaryl-phenylalanine methyl ester according to the present invention "JJ" can be used to synthesize aspartame as follows.

Aspartame synthesis using microorganisms or by bringing a culture of microorganisms capable of producing aspartame from FPM and ammonia or a processed product thereof into contact with FPM and ammonia. On the other hand, chemical synthesis is achieved by dissolving the substrate FPM and aqueous ammonia in a suitable solvent (for example, methanol) and refluxing the solution.

EXAMPLES The present invention will be explained in more detail in the following Examples, but it goes without saying that the technical scope of the present invention is not limited to these Examples.

216 ml of L-phenylalanine methyl ester hydrochloride was dissolved in dry DMF 5-, and while stirring, 101 ml of triethylamine was added. Fumaru fi11 to this
After adding 6 mg and 181 mg of DEPC and stirring for 2 minutes, 101 mg of triethylamine was added and 181 mg of DEPC was added.
After stirring for 0 minutes, the mixture was left refrigerated day and night. Next, after filtering off insoluble matter, the solvent was distilled off under reduced pressure, and the obtained oily substance was extracted with methylene chloride-saturated NaHCO3 water. After acidifying the aqueous layer with 2N-HCl, methylene chloride Extract with (
20 mff x 2 times). After drying over anhydrous Na2so4, the solvent was distilled off under reduced pressure, and recrystallization was performed from ether-n-pentane. This was collected by filtration and dried to obtain 60 mg of white crystals. The yield was 32.5%.

This crystalline compound has m, p, 148 to 149°C (uncorrected), specific light intensity [α] - + 47.5 <ethyl acetate, C = 1.6), and the results of elemental analysis are shown in Table 1. It was as shown in

Table 1 C (%) H (%) N (%) Calculated value C, 4H, 5N○s 60.64 5.
45 5.05 Actual value 59.0
B 5.47 5.16 In addition, the results of NMR-1IR-1 and MASS spectrogram of the obtained crystals and the results of N-maleonyl-phenylalanine methyl ester produced based on JP-A-48-52741 Melting point and NMJ? - By comparison with the spectrogram, the obtained crystal was identified as FPM.

Using this crystal as a standard, high-performance liquid chromatography (
The conditions for measuring FPM concentration in a solution by HPLC) are specified, and FPMi 1 degree in the reaction solution in the following examples is H
Measured by PLC. The conditions of this HPLC system are as follows.

Column: ODS pak F 411 (manufactured by Showa Denko@) Eluent: 0.005M Nil or l12PO4
? Liquid g Solvent Water: Methanol (volume ratio 1:4) Flow rate: 0.5 mI2/min Detection: UV 254 nm Note that the raw materials fumaric acid and L-phenylalanine methyl ester were also measured by HPLC under the same conditions.

Example 2 - L-phenylalanine methyl ester hydrochloride 216 [
+1? was dissolved in dry DM, F5-, and 101 ml of triethylamine was added while stirring. This contains fumaric acid 11
After adding 6■ and DEPC217■ and stirring for 2 minutes,
While cooling with water, 101 ml of triethylamine was added and stirred for 10 minutes. This reaction solution was converted into H PLC described in Example 1.
As analyzed by the system, 'FPM was produced with a yield of 70%. Note that L-phenylalanine methyl ester, one of the raw materials, did not remain, but fumaric acid remained. Formation of a by-product was observed, which is represented by the following formula]3 Example 3 Using dry dioxane as a solvent, the reaction was carried out in the same manner as in Example 2 at room temperature for 1 hour. Analysis of the reaction solution using an HPLC system revealed that the yield of FPM was 60% and the residual amount of fumaric acid was 20%. By-products similar to those in Example 2 were confirmed.

Example 4 Using dry tetrahydrofuran as a solvent, the reaction was carried out in the same manner as in Example 2 at room temperature for 1 hour.

The reaction solution was reddish brown. Analysis of the reaction solution using an HPLC system revealed that the yield of FPM was 56% and the residual amount of fumaric acid was 22%. Production of by-products similar to those in Example 2 was confirmed.

Example 5 The reaction was carried out in the same manner as in Example 2, except that dry methylene chloride was used as the solvent and the reaction was carried out at room temperature for 1 hour. Analysis of the reaction solution using an HPLC system revealed that the yield of FPM was 48% and the residual amount of fumaric acid was 26%. By-products similar to those in Example 2 were confirmed.

Example 6 A reaction was carried out at room temperature for 1 hour in the same manner as in Example 2 using dry pyridine as a solvent. Analysis of the reaction solution using an HPLC system showed that the yield of FPM was 52% and the remaining amount of fumaric acid was 2.
It was 4%. Furthermore, by-products similar to those in Example 2 were confirmed.

Example 7 216 quarts of L-phenylalanine methyl ester hydrochloride was dissolved in 5-5 dry DMF, and 101 quarts of triethylamine were added while stirring. To this, fumaric acid 116■ and D
After adding 248 mg of CC and stirring at room temperature for 1 hour, the mixture was left refrigerated day and night. When this reaction solution was analyzed using an If PLC system, the reaction was found to be incomplete, so the reaction temperature was lowered to 7.
After raising the temperature to 0°C and stirring for 1 hour, the reaction was completed and the reaction solution was analyzed by IPLC, and the yield of FPM was 24.
The remaining amount of fumaric acid was 38%. Furthermore, by-products similar to those in Example 2 were confirmed.

Example 8 116 cm of fumaric acid is dissolved in dry DMF and while stirring 344 cm of triethylamine and 130 cm of CIC0OEt are dissolved.
(2) was added and stirred at room temperature for 2 hours. At this time, the reaction solution took on a black color.

To this, L-phenylalanine methyl ester 216 r
After adding rg and stirring at room temperature for 1 hour, the mixture was left refrigerated - day and night. When this reaction solution was analyzed using an HPLC system, the yield of FPM was 47% and the residual fumaric acid, which was a raw material, was 25%. In addition, the formation of by-products that appeared to be multimers was observed.

As described in detail, according to the present invention, fumaric acid and L-phenylalanine methyl ester are used as raw materials, and by reacting them in a hydrogen-free polar solvent using a conventional condensing agent, a highly FPM can be produced in high yield.

This is an effect unique to the present invention that is not observed in a reaction using a condensing agent in a proton-donating solvent or in an acid chloride method.

Claims (1)

[Claims] 1. N-fumaryl-L-phenylalanine methyl ester represented by the formula ▲ Numerical formulas, chemical formulas, tables, etc. are available. 2. Trans-N-fumaryl-L represented by the above formula, which is produced by reacting fumaric acid and phenylalanine methyl ester in a hydrogen-free polar solvent using a dehydrating reagent.
-Production method of phenylalanine methyl ester.