WO1983001619A1 - METHOD FOR THE PREPARATION OF METHYL ESTER OF 'alpha'-ASPARTYL PHENYLALANINE - Google Patents

METHOD FOR THE PREPARATION OF METHYL ESTER OF 'alpha'-ASPARTYL PHENYLALANINE Download PDF

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WO1983001619A1
WO1983001619A1 PCT/FR1982/000181 FR8200181W WO8301619A1 WO 1983001619 A1 WO1983001619 A1 WO 1983001619A1 FR 8200181 W FR8200181 W FR 8200181W WO 8301619 A1 WO8301619 A1 WO 8301619A1
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isomer
product
mixture
methyl ester
phenylalanine
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PCT/FR1982/000181
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French (fr)
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Human-Pharm S.A. Laboratoires
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Gourbault, Maurice, Jean
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Priority to DE8282903246T priority Critical patent/DE3265673D1/en
Priority to AT82903246T priority patent/ATE15052T1/en
Priority to JP57503294A priority patent/JPS58501909A/en
Publication of WO1983001619A1 publication Critical patent/WO1983001619A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K5/00—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof
    • C07K5/04—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof containing only normal peptide links
    • C07K5/06—Dipeptides
    • C07K5/06104—Dipeptides with the first amino acid being acidic
    • C07K5/06113—Asp- or Asn-amino acid
    • C07K5/06121—Asp- or Asn-amino acid the second amino acid being aromatic or cycloaliphatic
    • C07K5/0613—Aspartame
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S530/00—Chemistry: natural resins or derivatives; peptides or proteins; lignins or reaction products thereof
    • Y10S530/801—Peptide sweetners

Definitions

  • the present invention relates to a process for the preparation of the methyl ester of ⁇ -aspartyl phenylalanine.
  • this aspartame must be used in the form of its ⁇ isomer because its ⁇ isomer is devoid of sweetening power and is, on the contrary, endowed with a bitter flavor.
  • the process used consists in carrying out in an aqueous basic medium, and in a known manner, the condensation of the methyl ester of phenylalanine with the anhydride of N-formyl L-aspartic acid and is characterized in that the product of said condensation reaction is treated in at least one column of ion-exchange resin in which acidification of said product is carried out in particular and that after recovery of the formylated ⁇ -isomer on the one hand and of a mixture of ⁇ -isomer and of the ⁇ -form isomer on the other hand, the said mixture of the ⁇ and ⁇ isomers is treated with acetic anhydride so as to obtain the corresponding aspartimide and then the product obtained with an acid so as to convert most of the isomer of the ⁇ isomer contained in said mixture and in ensuring the deformylation of these products.
  • the reaction product is therefore subjected to acidification by passage through an ion exchange column containing a resin of the sulfonic polystyrene type.
  • This passage has the result on the one hand of converting the sodium salts formed in the condensation reaction into corresponding acids on the other hand of carrying out a demineralization of the medium.
  • the ⁇ -form N-formyl aspartam thus obtained can be deformylated by known techniques, for example by treatment with dilute hydrochloric acid at temperatures between 30 and 75 ° C, so as to obtain the aspartame.
  • the isomerization of the ⁇ isomer is simultaneously carried out into the ⁇ isomer and the deformylation of the starting mixture by carrying out the transformation described below.
  • This transformation comprises: - in a first stage the reaction of the ⁇ isomer or of a mixture of the ⁇ and ⁇ isomer of aspartame with acetic anhydride; this reaction takes place between 10 and 70 ° C approximately in solution in the anhydride and leads to the formation of an aspartimide of formula:
  • this aspartimide is subjected to hydrolysis in solution and in an acid medium (pH between 2.5 and 3.5) to give rise to the ⁇ isomer of aspartame,
  • condensation reaction Treatment of the condensation product of the methyl ester of phenylalanine with N-formyl aspartic acid anhydride.
  • the condensation reaction was carried out using substantially equivalent amounts, by weight, of the two reactants and an aqueous sodium hydroxide solution.
  • the pH is adjusted to 8.5 and the temperature to 0 ° C.
  • the reaction lasts approximately two hours.
  • the cold solution obtained is percolated on a column of 0-20 sulfonic duolite resin; the volume of the column is proportional to the quantities to be treated and the elution rate is determined by solutions.
  • a very acidic percolate is obtained, the pH of which is adjusted to around 2.4 by addition of lime; the precipitated calcium sulphate is filtered. The filtrate is percolated again on this same column and under the same conditions, in particular to remove the unbound sodium and the remaining calcium. The percolate is concentrated under vacuum.
  • the crystals obtained contain at least 80% of the ⁇ isomer of N-formyl aspartam, and can be purified by recrystallization.
  • EXAMPLE 2
  • the precipitate (or oil) obtained is dissolved in methanol and a sufficient quantity of hydrochloric acid is added thereto so that the pH of the medium is between 2.5 and 3.5 approximately; it is heated for one hour at 60 ° C.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Biophysics (AREA)
  • General Health & Medical Sciences (AREA)
  • Genetics & Genomics (AREA)
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  • Peptides Or Proteins (AREA)

Abstract

Method for the preparation of methyl ester of alpha -aspartyl phenylalanine by reaction of methyl ester of the phenylalanine with the anhydride of N formyl aspartic acid, method wherein the product of said reaction is treated in at least one iron exchange resin column and wherein the beta isomer contained in the mixture obtained is isomerized by treatment with acetic anhydride followed by an acidic hydrolysis to transform said beta isomer into an alpha isomer and to provide for the deformylation of said product.

Description

Procédé de préparation de l'ester méthyllque de 1' α -aspartyl phenylalanine. Process for the preparation of the methyl ester of 1 α -aspartyl phenylalanine.
La présente invention concerne un procédé de préparation de l'ester méthylique de 1 'α -aspartyl phenylalanine. On sait que l'ester méthylique de l' α -aspartyl phenylalaninThe present invention relates to a process for the preparation of the methyl ester of α-aspartyl phenylalanine. We know that the methyl ester of α -aspartyl phenylalanin
(ou aspartam) est un édulcorant artificiel acalorique très recherché. Ses propriétés pharmacoiogiques et toxicologiques sont maintenant bien connues et son utilisation ne comporte aucun des risques que l'on attribue à l'utilisation des produits tels que la saccharine et le cyclohexylsulfamate.(or aspartame) is a highly sought after calorie-free artificial sweetener. Its pharmacological and toxicological properties are now well known and its use does not involve any of the risks that are attributed to the use of products such as saccharin and cyclohexylsulfamate.
On sait également que cet aspartam doit être utilisé sous forme de son isomère α car son isomère β est dépo-urvu de pouvoir sucrant et est doué, au contraire, d'une saveur amère.It is also known that this aspartame must be used in the form of its α isomer because its β isomer is devoid of sweetening power and is, on the contrary, endowed with a bitter flavor.
Il est donc souhaitable de disposer d'un procédé de synthèse simple de cet aspartam, ce procédé permettant de minimiser la .production de produits secondaires indésirables (et notamment de cet isomère β ) et comportant une technique de valorisation par transformation de cet isomère β en isomère α .It is therefore desirable to have a simple synthesis process for this aspartame, this process making it possible to minimize the production of undesirable secondary products (and in particular of this β isomer) and comprising a recovery technique by transformation of this β isomer into α isomer.
Le procédé utilise consiste a effectuer en milieu basique aqueux, et de façon connue, la condensation de l'ester-méthylique de la phenylalanine avec l'anhydride de l'acide N-formyl L - aspartique et est caractérisé en ce que le produit de ladite réaction de condensation est traité dans au moins une colonne de résine ëchangeuse d'ions dans laquelle se réalise notamment l'acidification dudit produit et qu'après récupération de 1'isomèreα N formylé d'une part et d'un mélange d'isomèreα et d'isomère β îî formyles d'autre part, on traite ledit mélange des isomèresα et β par l'anhydride acétiq de façon à obtenir l' aspartimide correspondant puis le produit obtenu par un acide de façon à transformer en isomèreα la plus grande partie de l' isomère β contenu dans ledit mélange et à assurer la déformylatio de ces produits.The process used consists in carrying out in an aqueous basic medium, and in a known manner, the condensation of the methyl ester of phenylalanine with the anhydride of N-formyl L-aspartic acid and is characterized in that the product of said condensation reaction is treated in at least one column of ion-exchange resin in which acidification of said product is carried out in particular and that after recovery of the formylated α-isomer on the one hand and of a mixture of α-isomer and of the β-form isomer on the other hand, the said mixture of the α and β isomers is treated with acetic anhydride so as to obtain the corresponding aspartimide and then the product obtained with an acid so as to convert most of the isomer of the β isomer contained in said mixture and in ensuring the deformylation of these products.
Comme il a été précisé la réaction de condensation de l'esterméthylique de la phenylalanine avec l'anhydride de l'acide N-formyl L-aspartique est connue. Elle est connue d'une part du fait qu'elle ne constitue qu'un emploi nouveau d'un procédé général de condensation de deux aminoacides et d'autre part du fait qu'elle a été décrite dans un certain nombre de documents parmi lesquels les brevets français 2.040.473, 2.078.640 et 2.160.471.As has been specified, the condensation reaction of the estermethyl of phenylalanine with the anhydride of N-formyl L-aspartic acid is known. It is known on the one hand from the fact that it constitutes only a new use of a general process for the condensation of two amino acids and on the other hand from the fact that it has been described in a number of documents including French patents 2,040,473, 2,078,640 and 2,160,471.
Cependant, les techniques par lesquelles, à la fin de la réaction de condensation décrite ci-dessus, on récupère les produits formés en vue de la préparation de l'isomère α pur de 1' aspartam ont une importance considérable pour la rentabilité dudit procédé et pour la possibilité d'obtention d'un produit final aussi pur que possible.However, the techniques by which, at the end of the condensation reaction described above, the products formed are recovered with a view to the preparation of the pure α-isomer of aspartam are of considerable importance for the profitability of said process and for the possibility of obtaining a final product as pure as possible.
Dans la présente invention le produit de réaction est donc soumis à une acidification par passage dans une colonne ëchangeuse d'ions contenant une résine de type polystyrène sulfonique. Ce passage a pour résultat d'une part de convertir les sels de sodium formés dans la réaction de condensation en acides correspondant d' autre part de réaliser une déminéralisation du milieu. On peut obtenir ainsi de façon très courante un produit (aspartam comportant un blocage formyl) contenant plus d'environ 80 % d'isomère α de N-formyl aspartam ; la teneur de l'éluat en cet isomère α est telle qu'il est possible, après concentration, de précipiter un produit cristallin solide par simple ensemencement de i'éluat concentré à l'aide de cristaux de l'isomère α du N-formyl aspartam.In the present invention, the reaction product is therefore subjected to acidification by passage through an ion exchange column containing a resin of the sulfonic polystyrene type. This passage has the result on the one hand of converting the sodium salts formed in the condensation reaction into corresponding acids on the other hand of carrying out a demineralization of the medium. It is thus very common to obtain a product (aspartame comprising a formyl blocking) containing more than approximately 80% of the α-isomer of N-formyl aspartame; the content of the eluate in this α-isomer is such that it is possible, after concentration, to precipitate a solid crystalline product by simple inoculation of the concentrated eluate using crystals of the α-isomer of N-formyl aspartame.
On voit l'intérêt d'un tel traitement.We see the benefit of such treatment.
Le N-formyl aspartam de forme α ainsi obtenu peut être déformylé par des techniques connues, par exemple par traitement à l'acide chlorhydrique dilué a des températures comprises entre 30 et 75° C, de façon à obtenir l' aspartam.The α-form N-formyl aspartam thus obtained can be deformylated by known techniques, for example by treatment with dilute hydrochloric acid at temperatures between 30 and 75 ° C, so as to obtain the aspartame.
Mais par ailleurs le procédé de condensation a donné naissance à du N-formyl aspartam de forme β qui est récupéré tel que ou qui le plus souvent se présente sous forme de mélanges avec le N-formyl aspartam de forme α . Il est donc souhaitable de disposer d'un procédé permettant de transformer cet isomère β en isomère α.However, moreover, the condensation process gave rise to N-formyl aspartame of β form which is recovered as or which most often occurs in the form of mixtures with N-formyl aspartam of α form. It is therefore desirable to have a process allowing this β isomer to be transformed into an α isomer.
Selon la présente invention on réalise simultanément l'isomêrisation de l'isomère β en isomère α et la déformylation du mélange de départ en réalisant la transformation décrite ci-apres. Cette transformation comporte : - dans un premier stade la réaction dé l'isomère β ou d un melljange d'isomère α et β de l'aspartam avec de l'anhydride acétique ; cette réaction a lieu entre 10 et 70°C environ en solution dans l'anhydride et conduit à la formation d'un aspartimide de formule :According to the present invention, the isomerization of the β isomer is simultaneously carried out into the α isomer and the deformylation of the starting mixture by carrying out the transformation described below. This transformation comprises: - in a first stage the reaction of the β isomer or of a mixture of the α and β isomer of aspartame with acetic anhydride; this reaction takes place between 10 and 70 ° C approximately in solution in the anhydride and leads to the formation of an aspartimide of formula:
Figure imgf000005_0001
Figure imgf000005_0001
- dans un deuxième stade cet aspartimide est soumis à une hydrolyse en solution et en milieu acide (pH entre 2,5 et 3,5) pour donner naissance à l'isomère α de l'aspartam,in a second stage, this aspartimide is subjected to hydrolysis in solution and in an acid medium (pH between 2.5 and 3.5) to give rise to the α isomer of aspartame,
- la solution obtenue est soumise à cristallisation pour la récupération du produit pur.- The solution obtained is subjected to crystallization for the recovery of the pure product.
L'exemple non limitatif suivant illustre les divers aspects de l'invention. EXEMPLE 1 :The following nonlimiting example illustrates the various aspects of the invention. EXAMPLE 1:
Traitement du produit de condensation de l'ester-méthylique de la phenylalanine avec l'anhydride de l'acide N-formyl aspartique. On a réalisé la réaction de condensation en utilisant des quantités sensiblement équivalentes, en poids, des deux réactifs et une solution aqueuse de soude. Le pH est ajusté à 8,5 et la température à 0° C. La réaction dure deux heures environ.Treatment of the condensation product of the methyl ester of phenylalanine with N-formyl aspartic acid anhydride. The condensation reaction was carried out using substantially equivalent amounts, by weight, of the two reactants and an aqueous sodium hydroxide solution. The pH is adjusted to 8.5 and the temperature to 0 ° C. The reaction lasts approximately two hours.
La solution froide obtenue est percolée sur une colonne de résine duolite 0-20 sulfonique ; le volume de la colonne est proportion nel aux quantités à traiter et le débit d'élution est déterminé par des solutions.The cold solution obtained is percolated on a column of 0-20 sulfonic duolite resin; the volume of the column is proportional to the quantities to be treated and the elution rate is determined by solutions.
On obtient un percolat très acide dont on ajuste le pH a environ 2,4 par addition de chaux ; on filtre le sulfate de calcium précipité. Le filtrat est à nouveau percolé sur cette même colonne et dans les mêmes conditions pour notamment en éliminer le sodium non fixé et le calcium restant. Le percolat est concentré sous vide.A very acidic percolate is obtained, the pH of which is adjusted to around 2.4 by addition of lime; the precipitated calcium sulphate is filtered. The filtrate is percolated again on this same column and under the same conditions, in particular to remove the unbound sodium and the remaining calcium. The percolate is concentrated under vacuum.
On obtient une solution qui, par simple adjonction de cristaux de N-formyl α aspartam, cristallise.A solution is obtained which, by the simple addition of crystals of N-formyl α aspartam, crystallizes.
Les cristaux obtenus contiennent au moins 80 % de l'isomère α du N-formyl aspartam, et sont purifiables par recristallisation. EXEMPLE 2 :The crystals obtained contain at least 80% of the α isomer of N-formyl aspartam, and can be purified by recrystallization. EXAMPLE 2:
Isomérisation et dëformylation de mélange d'isomère α et β de N-formyl-aspartam.Isomerization and deformylation of mixture of α and β isomer of N-formyl-aspartam.
En effectuant la réaction de condensation décrite dans 1 'exemplelon a obtenu également une solution contenant en proportions sensiblement analogues de l' isomère α du N-formyl aspartam et de l'isomère β de ce même produit.By carrying out the condensation reaction described in one example, a solution was also obtained containing, in substantially similar proportions, the α-isomer of N-formyl aspartam and the β-isomer of this same product.
Cette solution a été traitée comme suit :This solution was treated as follows:
- on admet dans un réacteur environ 2 kg de ce précipite et 10 kg d'anhydride acétique ; on porte le mélange à 60° C pendant une heure ; on concentre sous vide jusqu'à l'obtention d'un précipité ou d'une huile.- About 2 kg of this precipitate and 10 kg of acetic anhydride are admitted to a reactor; the mixture is brought to 60 ° C for one hour; concentrated in vacuo until a precipitate or an oil is obtained.
- le précipité (ou l'huile) obtenu est dissout dans le methanol et on y ajoute une quantité suffisante d'acide chlorhydrique pour que le pH du milieu soit compris entre 2,5 et 3,5 environ ; on chauffe pendant une heure â 60° C.- The precipitate (or oil) obtained is dissolved in methanol and a sufficient quantity of hydrochloric acid is added thereto so that the pH of the medium is between 2.5 and 3.5 approximately; it is heated for one hour at 60 ° C.
- par cristallisation on obtient directement de l'isomère α d' aspartam. Dans ces réactions on a réalise simultanément l' isomérisation de l'isomère β du N-formyl aspartam et la déformylation de cet isomère. - By crystallization, the α isomer of aspartame is obtained directly. In these reactions, the isomerization of the β isomer of N-formyl aspartam and the deformylation of this isomer were carried out simultaneously.

Claims

REVENDICATIONS
1. Procédé pour la préparation de l'ester-méthylique de l'α -aspartyl phenylalanine selon lequel on effectue en milieu basique aqueux, et de façon connue, la condensation de l'esterméthylique de la phenylalanine avec l'anhydride de l'acide N-formyl-L aspartique, ledit procédé étant caractérisé en ce que le produit de ladite réaction de condensation est traité dans au moins une colonne de résine ëchangeuse d'ions dans laquelle se réalise notamment l'acidification dudit produit et qu'après récupération de l'isomèreα N formylé d'une part et d'un mélange d'isomères et d'isomère B N formylés d'autre part, on traite ledit mélange des isomères α et β par l'anhydride acétique de façon à obtenir l'aspartimide correspondant puis le produit obtenu par un acide de façon à transformer en isomèreα la plus grande partie de l'isomère β contenu dans ledit mélange et à assurer la déforraylation de ces produits.1. Process for the preparation of the methyl-ester of α-aspartyl phenylalanine according to which, in an aqueous basic medium, and in known manner, the condensation of the methyl ester of phenylalanine with the acid anhydride is carried out N-formyl-L aspartic, said process being characterized in that the product of said condensation reaction is treated in at least one column of ion-exchange resin in which the acidification of said product is carried out and only after recovery of the α N isomer formylated on the one hand and a mixture of isomers and BN isomer formylated on the other hand, said mixture of the α and β isomers is treated with acetic anhydride so as to obtain the corresponding aspartimide then the product obtained with an acid so as to transform the greater part of the β isomer contained in said mixture into the α-isomer and to ensure the deforraylation of these products.
2. Procédé selon la revendication 1, caractérisé en ce que ledit traitement du mélange des isomères α et β N formylés par l'anhydride acétique est effectué en solution dans l'anhydride acétique a une température comprise entre 10 et 70°C environ. 2. Method according to claim 1, characterized in that said treatment of the mixture of the isomers α and β N formylated with acetic anhydride is carried out in solution in acetic anhydride at a temperature between 10 and 70 ° C approximately.
3. Procédé selon la revendication 2, caractérisé en ce que le deuxième stade de la réaction d' isomérisation consiste à réaliser l'hydrolyse à un pH compris entre 2,5 et 3,5 au moyen de l'acide chlorhydrique. 3. Method according to claim 2, characterized in that the second stage of the isomerization reaction consists in carrying out the hydrolysis at a pH between 2.5 and 3.5 using hydrochloric acid.
PCT/FR1982/000181 1981-11-06 1982-11-05 METHOD FOR THE PREPARATION OF METHYL ESTER OF 'alpha'-ASPARTYL PHENYLALANINE WO1983001619A1 (en)

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Application Number Priority Date Filing Date Title
DE8282903246T DE3265673D1 (en) 1981-11-06 1982-11-05 Process for preparing of methyl ester of alpha-aspartyl phenyl alanine
AT82903246T ATE15052T1 (en) 1981-11-06 1982-11-05 PROCESS FOR PRODUCTION OF ALPHA-ASPARTYLPHENYLALAMINE METHYLESTER.
JP57503294A JPS58501909A (en) 1981-11-06 1982-11-05 Method for producing α-aspartyl phenylalanine methyl ester

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FR8120877A FR2516077A1 (en) 1981-11-06 1981-11-06 PROCESS FOR THE PREPARATION OF ESTER-METHYLIC OF A-ASPARTYL PHENYLALANINE
FR81/20877811106 1981-11-06

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0297560A2 (en) * 1987-06-30 1989-01-04 Ajinomoto Co., Inc. Imides; a process for their production and a process for the production of dipeptides using them
EP0471833A1 (en) * 1990-03-12 1992-02-26 Nutrasweet Co Method for increasing the alpha to beta ratio in an aspartame coupling reaction.
EP0514936A1 (en) * 1991-05-23 1992-11-25 Ajinomoto Co., Inc. Method of preparing alpha-L-aspartyl-L-phenylalanine methyl ester

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3444915A1 (en) * 1984-12-08 1986-06-12 Hoechst Ag, 6230 Frankfurt N-MALEYL-PHENYLALANINALKYLESTER, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR THE PRODUCTION OF N-FUMARYLPHENYLALANINALKYLESTERS
JPH0680074B2 (en) * 1985-07-01 1994-10-12 味の素株式会社 Method for producing N-formyl-L-α-aspartyl-L-phenylalanine

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE791544A (en) * 1971-11-19 1973-05-17 Stamicarbon PREPARATION OF ALKYL ESTERS OF DIPEPTIDE
JPS5235660B2 (en) * 1972-05-25 1977-09-10
US4017472A (en) * 1973-03-05 1977-04-12 G. D. Searle & Co. Process for isolation of aspartyl dipeptide esters
US3931521A (en) * 1973-06-29 1976-01-06 Hughes Aircraft Company Dual spectrum infrared fire detector
US3825754A (en) * 1973-07-23 1974-07-23 Santa Barbara Res Center Dual spectrum infrared fire detection system with high energy ammunition round discrimination
JPS51113841A (en) * 1975-03-28 1976-10-07 Ajinomoto Co Inc Process for preparing lower alkyl esters of n-formyl-alpha -l-aspartyl-l-phenylalanine
JPS5494384A (en) * 1978-01-09 1979-07-26 Murata Manufacturing Co Infrared ray detector
JPS5494385A (en) * 1978-01-10 1979-07-26 Murata Manufacturing Co Infrared ray detector
JPS6049199B2 (en) * 1979-04-10 1985-10-31 東ソー株式会社 Purification method of α-L-aspartyl-L-phenylalanine lower alkyl ester
JPS57142523A (en) * 1981-02-28 1982-09-03 Toyoda Gosei Co Ltd Flame detector

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, Vol. 86, No. 21, 23 May (Columbus, Ohio, US), see page 505, Abstract No. 155982W, JP,A, 76113841, 07 October 1976, Ajinomonto Co. Inc. *
Journal of the Chemical Society, 1955 A.R. BATTERSBY et al.: 'Studies on Specific Chemical Fission of Peptide Links. Part I. The Rearrangement of Aspartyl and Glutamyl Peptides', see pages 259-269 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0297560A2 (en) * 1987-06-30 1989-01-04 Ajinomoto Co., Inc. Imides; a process for their production and a process for the production of dipeptides using them
EP0297560A3 (en) * 1987-06-30 1989-07-12 Ajinomoto Co., Inc. Imides; a process for their production and a process for the production of dipeptides using them
EP0471833A1 (en) * 1990-03-12 1992-02-26 Nutrasweet Co Method for increasing the alpha to beta ratio in an aspartame coupling reaction.
EP0471833A4 (en) * 1990-03-12 1993-06-16 The Nutrasweet Company Method for increasing the alpha to beta ratio in an aspartame coupling reaction
EP0514936A1 (en) * 1991-05-23 1992-11-25 Ajinomoto Co., Inc. Method of preparing alpha-L-aspartyl-L-phenylalanine methyl ester
US5266719A (en) * 1991-05-23 1993-11-30 Ajinomoto Co., Inc. Method of preparing α-L-aspartyl-L-phenylalanine methyl ester

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FR2516077A1 (en) 1983-05-13
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EP0093128B1 (en) 1985-08-21
JPS58501909A (en) 1983-11-10
ATE15052T1 (en) 1985-09-15

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