Claims
- 1. A process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester which comprises treating N-formyl-.alpha.-L-aspartyl-L-phenylalanine as a raw material in methanol in the presence of an acid to form .alpha.-L-aspartyl-L-phenylalanine dimethyl ester as a primary product, hydrolyzing the .alpha.-L-aspartyl-L-phenylalanine dimethyl ester by bringing it into contact with hydrochloric acid in the presence of methanol as desired, separating the thereby-deposited .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride and neutralizing said hydrochloride.
- 2. A process as claimed in claim 1 wherein the N-formyl-.alpha.-L-aspartyl-L-phenylalanine used as a raw material contains N-formyl-.beta.-L-aspartyl-L-phenylalanine in an amount of 30% by weight or less.
- 3. A process as claimed in claims 1 or 2 wherein the acid is an inorganic acid.
- 4. A process as claimed in claims 1 or 2 wherein the acid is an organic sulfonic acid.
- 5. A process as claimed in claims 1 or 2 wherein the temperature of the treatment by which .alpha.-L-aspartyl-L-phenylalanine dimethyl ester is formed is 10.degree.-70.degree. C.
- 6. A process as claimed in claims 1 or 2 wherein the concentration of hydrochloric acid with which .alpha.-L-aspartyl-L-phenylalanine dimethyl ester is brought into contact is 3-30% by weight in terms of [HCl/(HCl +water)].times.100.
- 7. A process as claimed in claims 1 or 2 wherein the amount of hydrochloric acid used is 0.5-10 moles per mole of N-formyl-.alpha.-L-aspartyl-L-phenylalanine used as a raw material, or per mole of a mixture of N-formyl-.alpha.-L-aspartyl-L-phenylalanine and N-formyl-.beta.-L-aspartyl-L-phenylalanine when the raw material contains the .beta.-isomer.
- 8. A process as claimed in claims 1 or 2 wherein the amount of methanol present as required upon hydrolyzing .alpha.-L-aspartyl-L-phenylalanine dimethyl ester by bringing it into contact with hydrochloric acid to prepare .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride is 5 moles or less per mole of N-formyl-.alpha.-L-aspartyl-L-phenylalanine used as a raw material, or per mole of a mixture of N-formyl-.alpha.-L-aspartyl-L-phenylalanine and N-formyl-.beta.-L-aspartyl-L-phenylalanine when the raw material contains the .beta.-isomer.
- 9. A process as claimed in claims 1 or 2 wherein the temperature at which .alpha.-L-aspartyl-L-phenylalanine dimethyl ester is brought into contact with hydrochloric acid is 0.degree.-50.degree. C.
Priority Claims (2)
Number |
Date |
Country |
Kind |
59-273701 |
Dec 1984 |
JPX |
|
60-36530 |
Feb 1985 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 063,736, filed June 17, 1987, now abandoned.
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Continuations (2)
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Number |
Date |
Country |
Parent |
63736 |
Jun 1987 |
|
Parent |
809800 |
Dec 1985 |
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