- A SUPERIOR SYNTHESIS OF ASPARTAME
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The dipeptide sweetener aspartame has been prepared in high yield via the coupling of L-phenylalanine methyl ester and L-aspartic acid N-thiocarboxyanhydride.
- Vinick, Fredic J.,Jung, Stanley
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- Investigation of solid-state reactions using variable temperature X-ray powder diffractrometry. I. Aspartame hemihydrate
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Purpose. The object of this study was to demonstrate the applicability of variable temperature X-ray powder diffractometry (XRD) to investigate solid-state reactions using aspartame as a model compound. Methods. Aspartame exists as a hemihydrate (ASH) under ambient conditions and converts to aspartame anhydrate (ASA) at ～130°C. ASA on further heating to ～180°C undergoes decomposition (intramolecular cyclization) to form a diketopiperazine derivative (DKP). The dehydration as well as the decomposition kinetics were studied isothermally at several temperatures. The unique feature of this technique is that it permits simultaneous quantification of the reactant as well as the product. Results. While the dehydration of ASH appeared to follow first-order kinetics, the cyclization of ASA was a nucleation controlled process. The rate constants were obtained at various temperatures, which permitted the calculation of the activation energies of dehydration and cyclization from the Arrhenius plots. The activation energy of dehydration was also calculated according to the method described by Ng (Aust. J. Chem., 28:1169-1178, 1975) and the two values were in good agreement. Conclusions. The study demonstrates that XRD is an excellent complement to thermal analysis and provides direct information about the solid-states of various reaction phases.
- Rastogi,Zakrzewski,Suryanarayanan
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- Molecularly imprinted polymeric adsorbents for byproduct removal
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In this study, both diastereo- and enantioselective adsorbents for a dipeptide derivative were prepared using a molecular imprinting technique. The diastereo- and enantioisomers for the dipeptide derivative N-(benzyloxycarbonyl)aspartylphenylalanine methyl ester (ZAPM), in addition to the α- and β-isomers, were chosen as test compounds for the investigation of the imprinting effect. The close similarities between the structures of different isomers make it possible to interpret the roles of template structure on specific molecular recognition. A highly specific byproduct scavenger was prepared by simultaneously incorporating methacrylic acid and vinylpyridine as functional monomers. The binding selectivities of polymeric adsorbents for the α- and β-isomers are shown to be greatly enhanced by introducing enantiocomplementarities into the polymer matrixes. An anti-β-L,L-ZAPM polymer was applied in a solid-phase extraction protocol, for the purification of the product in the chemical synthesis of N-protected aspartame. Finally, polymer beads were also imprinted against β-L,L-ZAPM using suspension polymerization performed in perfluorocarbon fluid. The imprinted polymer beads displayed the same binding characteristics as the imprinted bulk polymer and can be envisaged for the use of product purification in chromatographic mode.
- Ye, Lei,Ramstroem, Olof,Mosbach, Klaus
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- STUDIES ON AMINO ACIDS AND PEPTIDES - VII SYNTHESES OF ASPARTAME AND THIOASPARTAME
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The protected aspartame, 4, has been prepared from the benzyl ester of N-benzyloxycarbonyl-S-aspartic acid, 1, and the methyl S-phenylalanate, 3, using 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, LR, as a coupling reagent.Another protected aspartame, 7, has been prepared from the tert-butyl ester of 1--succinimide, 6, and methyl S-phenylalanate, 3.Thiations of 4/7 by LR produces a protected thioaspartame, 5/9.Deprotection of 7 and 9 gives aspartame, 8, and the slightly sweet thioaspartame, 10, in high yields.
- Yde, B.,Thomsen, I.,Thorsen, M.,Clausen,K.,Lawesson, S.-O.
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- Synthesis of β-lactam peptidomimetics through Ugi MCR: First application of chiral Nβ-Fmoc amino alkyl isonitriles in MCRs
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Chiral Nβ-Fmoc amino alkyl isonitriles were employed in Ugi multi component reactions (Ugi 4C-3CR) to obtain functionalized β-lactam peptidomimetics with l-aspartic acid α-methyl ester/peptide ester and organic aldehydes. The reactions were carried out in MeOH. Thirteen Ugi products have been prepared in good to moderate yields with good diastereoselectivities.
- Vishwanatha,Narendra,Sureshbabu, Vommina V.
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p. 5620 - 5624
(2011/11/06)
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- METHOD FOR THE SYNTHESIS OF PEPTIDES WITHOUT SOLVENT
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The disclosure relates to a method for the synthesis of a compound of the formula (I) in which: n is an integer higher than or equal to 1; Rb and each Rn are independently a hydrogen atom, a C1-C6 arylalkyl group or a C1-C6 alkyl group substituted or not by an aryl group, —COOH, C1-C6, —COO-(alkyl), —CONH2, —SH, heteroaryl, —NH2, —NHC(NH)(NH2), C1-C6-s-(alkyl), —OH or phenol; Ra is a N-protective group; Rc is a ORd group in which Rd is a C1-C6 alkyl group or a NReRf group in which Re and Rf Re independently an N-protective group.
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Page/Page column 6
(2010/02/17)
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- Solvent-free synthesis of peptides
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Chamical Equation Presentation A crush on sweetness! The coupling of a urethane-protected N-carboxyanhydride of an amino acid with another amino acid derivative under ball-milling conditions gives a protected dipeptide in very high yield (see scheme; PG: protecting group). The reaction takes place in the solid state. The synthesis was applied to the preparation of a tri peptide and the sweetener aspartame, without any organic solvent or purification.
- Declerck, Valerie,Nun, Pierrick,Martinez, Jean,Lamaty, Frederic
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supporting information; experimental part
p. 9318 - 9321
(2010/03/24)
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- Hexafluoroacetone as protection and activation reagent in amino acid and peptide chemistry regiospecific α-functionalization of aspartic acid
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A highly efficient method for regiospecific α-functionalization of aspartic acid is described. Key step is the synthesis of a N-protected and regioselectively α-carboxy-activated heterocyclic intermediate from aspartic acid and hexafluoroacetone. The new strategy offers i.a. a two step access to the sweetener Aspartame and to libraries of aspartame analogues.
- Burger, Klaus,Lange, Torsten,Rudolph, Martin
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p. 189 - 198
(2007/10/03)
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- Immobilized thermolysin and synthesis of precursor of aspartame
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The optimal condition of the thermolysin-catalysed condensation reaction of N-benzyloxycarbonyl-DL-aspartic acid (Z-DL-Asp) with DL-phenylalanine methyl ester (DL-Phe-OMe) giving N-benzyloxycarbonyl-L-aspartyl-L-phenylalanine methyl ester, the precursor of the synthetic sweetener (aspartame, APM) has been investigated.The immobilized thermolysins have been prepared using seven polymethacrylate derivatives as carrier by covalent coupling of the polymers with enzyme.Seven derivatives have been synthesized using methacrylic acid, p-hydroxybenzoic acid and thecorresponding activated amide or amine.The abilities of the immobilized thermolysis to catalyze the condensation reaction have been tested and 100percent yield has been obtained by using one of them.
- Zhou, Qingzhong,Huang, Zhen
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- Hexafluoroacetone as Protecting Group and Activating Reagent in Amino Acid and Peptide Chemistry, XI. A New Simple Preparative Access to 2,5-Dioxopiperazines and 2,5-Dioxomorpholines
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2,5-Dioxopiperazines with symmetrical as well as unsymmetrical substituent pattern can be obtained via 2,2-bis(trifluoromethyl)-1,3-oxazolidin-5-ones, and 2,5-dioxomorpholines via 2,2-bis(trifluoromethyl)-1,3-dioxolan-4-ones, respectively. Keywords: Hexafluoroacetone; α-Amino acids; α-Hydroxy acids; 2,2-Bis(trifluoromethyl)-1,3-oxazolidin-5-ones; 2,2-Bis(trifluoromethyl)-1,3-dioxolan-4-ones; 2,5-Dioxopiperazines; 2,5-Dioxomorpholines.
- Burger, K.,Rudolph, M.,Windeisen, E.,Worku, A.,Fehn, S.
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p. 453 - 464
(2007/10/02)
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- Porous pharmaceutical form and its preparation
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New porous, unitary freeze-dried pharmaceutical form, of homogeneous appearance, consisting of: a) an inclusion compound comprising: one or optionally more active substances, a predetermined quantity of cyclodextrin, optionally an additive facilitating inclusion, b) at least one substance chosen from: diluents, binders; and c) optionally one or more additives.
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- Process for the drying and granulation of aspartame
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The invention relates to a process for the drying and granulation of aspartame through the thermal treatment of a wet mass of aspartame crystals using a hot carrier gas, characterised in that a wet mass of aspartame crystals is supplied, in a continuous process, to a high-speed paddle dryer fitted with a jacket heated to a temperature of 80-190°C and with paddles, mounted on a central shaft with a controllable speed of rotation, at an adjustable distance from and angle to the jacket, which are positioned so that the required particle size of the granules is realized, the speed of rotation being chosen so that the Froude number is higher than 1, and the supplied product is treated in the paddle dryer for 15-600 seconds, with the simultaneous presence of a carrier gas having an inlet temperature of 100-200°C, and the granular product obtained is discharged from the paddle dryer and, if necessary, dried further - in a manner known per se - in one or more drying steps in other drying equipment. With the use of high-speed paddle dryer aspartame with good microbiological properties is very easily obtained.
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- Enzymic synthesis design and enzymic synthesis of aspartame
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An enzymic synthesis of aspartame (H-Asp-Phe-OMe) has been designed and realized based on the structure-activity study of thermolysin and penicillin amidase hydrolysis of its p-substituted phenylacetyl derivatives. These compounds meet the structural and energetic requirements of two enzymic binding sites. The peptide sweetener has been prepared by thermolysin - catalyzed condensation of the p-substituted phenylacetyl-Asp-OH and H-Phe-OMe follwed by penicillin amidase - catalyzed deprotection of the resulted aspartame precursors.
- Stoineva,Galunsky,Lozanov,Ivanov,Petkov
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p. 1115 - 1122
(2007/10/02)
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- Process for preparing peptide synthons
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The present invention relates to a process for preparing peptide synthons in which the optical purity of each of the peptides to be condensed is retained. According to this process, a silyl derivative of an amino acid or peptide, which is activated by a complex chloroimmonium salt, a complex coordinated phosphorus halide, oxyhalide salt or a complex oxalyl halide salt, is prepared. The activated peptide is then condensed with an N-silyl amino acid or peptide in which the acid group is protected.
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- Deblocking N-formyl aspartame compounds
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N-formyl amino acid or peptide is deformylated by reaction with aniline or methylene dianiline over noble metal catalyst, e.g., Pt-on-carbon. N-formanilide is formed as by-product. The process is particularly useful in deformylating N-formyl aspartame.
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- Encapsulation composition for use with chewing gum and edible products
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The present invention is method and composition for protecting an active ingredient and providing controlled release therefor, especially in a chewing gum composition, which includes a high molecular weight polyvinyl acetate blended with a hydrophobic plasticizer which forms a film with the high molecular weight polyvinyl acetate in the absence of an added solvent therefor. The active ingredient, such as the artificial sweetener aspartame, is blended into the encapsulating composition as, for example, by melt blend which can then be cooled to a solid and ground into particulate. The encapsulated active ingredient can then be used in a composition for ingestion by a human in the form of, for example, a chewing gum with extended shelf life and highly controlled release of the active ingredient.
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- STEREOCONTROLLED SYNTHESES OF ASPARTAME AND ITS (R)-ASPARTYL CONGENER VIA NITRONE CYCLOADDITION
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The title compounds have been synthesised via cycloaddition of nitrones (3a,b,c) to 2-chloroacrylonitrile.
- Keirs, David,Overton, Karl
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p. 841 - 848
(2007/10/02)
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- Process for producing α-L-aspartyl-L-phenylalanine methyl ester
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A process for preparing an α-L-aspartyl-L-phenylalanine methyl ester which comprises the steps of reacting formyl-L-aspartic anhydride with L-phenylalanine in the presence of water at a high pH, to produce formyl-α-L-aspartyl-L-phenylalanine; removing the formyl group from the formyl-α-L-aspartyl-L-phenylalanine and esterifying the resultant compound with methanol and hydrogen chloride to produce the hydrogen chloride salt of α-L-aspartyl-L-phenylalanine methyl ester; neutralizing the hydrogen chloride salt of α-L-aspartyl-L-phenylalanine methyl ester; and filtering the neutralized solution to produce α-L-aspartyl-L-phenylalanine methyl ester.
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- Tripeptides and sweetening agents containing the same
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Tripeptide sweeteners represented by formula (I) wherein X is glycine or a D or DL-isomer of alanine, α-aminobutyric acid, serine, threonine, norvaline, asparagine, B-methyl aspartate, proline or pipecolic acid, and Y is a D, L or DL-isomer of alanine, phenylalanine, phenylglycine, serine or β-aminobutyric acid or a salt thereof, and R is methyl, ethyl, propyl or isopropyl, are disclosed.
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- Process for producing α-aspartyl-phenylalanine ester
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The present invention relates to a process for producing α-aspartyl-phenylalanine ester represented by the general formula STR1 wherein R' represents an alkyl group having 1 to 4 carbon atoms, by reducing an N-protected-N-hydroxymethyl-α-aspartyl-phenylalanine ester represented by the general formula STR2 wherein R represents an organic mioety which can be substituted reductively by hydrogen, and R' is as defined above, with hydrogen gas or formic acid, in the presence of a reduction catalyst and an aromatic primary amine. According to the present invention, there can be obtained a high purity α-aspartyl-phenylalanine ester with a high yield.
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- Process for the preparation of alfa-L-aspartyl-L-phenyl-alanine alkyl esters
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A new process for preparing alfa-L-aspartyl-L-phenylalanine alkyl esters of formula I STR1 wherein R represents an alkyl group having from 1 to 5 carbon atoms, starting from the corresponding alfa-haloacyl-alfa-L-aspartyl-L-phenylalanine alkyl esters.
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- Process for preparing α-aspartyl-L-phenylalanine methyl ester
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A process for preparing α-L-aspartyl-L-phenylalanine methyl ester consisting of: bringing N-formyl-L-aspartic anhydride and L-phenylalanine methyl ester, in a molar ratio equal or approximately equal to 1:1, into contact with a solid cation exchange resin having free sulphonic, phosphonic or carboxylic acid groups, the ration of the acid equivalents of said resin acid groups to the number of moles of the one or other reagent being equal to or less than about 1:1, and operating in the liquid phase in an inert organic solvent at a temperature of about 40° C. or less, until a mixture of N-formyl-α-L-aspartyl-L-phenylalanine methyl ester and N-formyl-β-L-aspartyl-L-phenylalanine methyl ester forms in which the α isomer prevails over the β isomer; deformylating said N-formyl-α-L-aspartyl-L-phenylalanine methyl ester and N-formyl-β-L-aspartyl-L-phenylalanine methyl ester; and separating and recovering the α-L-aspartyl-L-phenylalanine methyl ester from said deformylated products.
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- Aspartame synthesis
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A process for the preparation of the N-L-α-aspartyl-L-phenylalanine 1-methyl ester (aspartame) which is characterized by adding phosphoric acid and a lower alkyl alcohol to the reaction mixture containing N-formyl α-L-aspartyl- and β-L-aspartyl-L-phenyl-alanine methyl ester and only one of the resultant deformylated isomers, i.e. aspartame phosphate precipitates. The α-isomer phosphate is collected by filtration and converted to free aspartame by treatment with a base.
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- Process for the preparation of α-L-aspartyl-L-phenylalanine methyl ester
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A regioselective process for the preparation of α-L-aspartyl-L-phenylalanine methyl ester is disclosed. A controlled aqueous coupling reaction between β-methyl-L-aspartate-N-carboxyanhydride and L-phenylalanine produces the aspartyl methyl ester of α-L-aspartyl-L-phenylalanine which is subsequently hydrolyzed and selectively esterified without isolation. The hydrochloride salt of α-L-aspartyl-L-phenylalanine methyl ester, which is selectively precipitated from the esterification mixture, can be neutralized to α-L-aspartyl-L-phenylalanine methyl ester.
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- IMMOBILIZED PENICILLINACYLASE: APPLICATION TO THE SYNTHESIS OF THE DIPEPTIDE ASPARTAME
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Immobilized penicillinacylase efficently catalyzes the conversion at pH 7.5 of N-phenacetyl aspartame (4) into aspartame (2) and phenylacetic acid.
- Fuganti, Claudio,Grasselli, Piero,Casati, Paolo
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p. 3191 - 3194
(2007/10/02)
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- Aspartame synthesis
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A process for deformylation and separation of N-formyl-L- α-aspartyl-L-phenylalanine methyl ester from a mixture containing both α and β isomers thereof, which comprises admixing with said isomeric mixture hydrogen peroxide and an organic acid.
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- Method for manufacture of N-formylaspartic anhydride
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In a method for the manufacture of N-formylaspartic acid anhydride which comprises reacting a mixture of aspartic acid, formic acid and acetic anhydride in the presence of an entraining organic solvent, the improvement comprising adding to the mixture, prior to or during the course of reaction, an oxide, hydroxide, or a salt of a metal. The above compound is used as an intermediate in the manufacture of alpha-L-aspartyl-L-phenylalanine methyl ester which is a sweetening agent.
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- Method and intermediates for producing α-L-aspartyl-L-phenylalanine
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This invention encompasses a method and intermediates for preparing a commercial sweetening agent, α-L-aspartyl-L-phenylalanine methyl ester. The process involves reacting L-aspartic acid with diketene to form N-acetoacetyl-L-aspartic acid which is converted to N-acetoacetyl-L-aspartic anhydride by reaction with acetic anhydride. N-acetoacetyl-L-aspartic anhydride is reacted with L-phenylalanine methyl ester to provide N-acetoacetyl-α-L-aspartyl-L-phenylalanine methyl ester which is converted to α-L-aspartyl-L-phenylalanine methyl ester by reaction with hydroxylamine hydrochloride.
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- Process for the preparation of lower alkyl esters of N-L-α-aspartyl-L-phenylalanine and of new intermediates for their preparation
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The invention relates to a selective process for the preparation of N-L-α-aspartyl-L-phenylalanine-1-lower alkyl ester which comprises: A. reacting an L-aspartic acid 4-arylmethyl ester with a (i) 1,3-diketone; or (ii) acylacetic ester; in the presence of a base to form the salt of (i') L-N-(1-alkyl-2-acyl-vinyl)-aspartic acid 4-arylmethyl ester; or (ii') L-N-(1-alkyl-2-alkoxycarbonyl-vinyl)-aspartic acid 4-arylmethyl ester, and then either: (1) reacting salt (i') or (ii') with an organic or inorganic acid halide having the formula X-A, wherein X represents a halogen and A has the meaning indicated hereinafter, or with an acid anhydride to form STR1 wherein R represents an alkyl radical with 1 to 6 carbon atoms; R' represents an alkyl or alkoxy radical with 1 to 6 carbon atoms; Ar represents the phenyl, nitrophenyl, halogenphenyl or alkylphenyl radical; and A represents an acyl with 2 to 12 carbon atoms, alkoxycarbonyl with 2 to 12 carbon atoms, or a phosphoric acid, phosphorous acid, sulfuric acid, sulfurous acid or sulfonic acid radical; and reacting ester (I) with an L-phenylalanine lower alkyl ester; or (2) reacting a salt of (i') or (ii') with a phosphorazo-L-phenyl lower alkyl ester; to form (i") N-L-α-N'-(1-alkyl-2-acyl-vinyl)-aspartyl-L-phenylalanine-1-lower alkyl-4-arylmethyl ester; or (ii") N-L-α-N'-(1-alkyl-2-alkoxycarbonyl)aspartyl-L-phenylalanine-1-lower alkyl-4-arylmethyl ester; B. reacting (i") or (ii") with a strong acid to split off the respective N-(1-alkyl-2-acyl-vinyl) or N-(1-alkyl-2-alkoxycarbonyl-vinyl) protective group and produce: (iii) N-L-α-aspartyl-L-phenylalanine-1-lower alkyl-4-(arylmethyl)ester; and C. subjecting ester (iii) to catalytic hydrogenation to selectively split off the 4-(arylmethyl)-ester group and leave the N-L-α-aspartyl-L-phenylalanine-1-lower alkyl ester product. Novel intermediates for the synthesis are also disclosed.
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- Method and intermediates for producing α-L-aspartyl-L-phenylalanine
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This invention encompasses a method and intermediates for preparing a commercial sweetening agent, α-L-aspartyl-L-phenylalanine methyl ester. The process involves reacting L-aspartic acid with diketene to form N-acetoacetyl-L-aspartic acid which is converted to N-acetoacetyl-L-aspartic anhydride by reaction with acetic anhydride. N-acetoacetyl-L-aspartic anhydride is reacted with L-phenylalanine methyl ester to provide N-acetoacetyl-α-L-aspartyl-L-phenylalanine methyl ester which is converted to α-L-aspartyl-L-phenylalanine methyl ester by reaction with hydroxylamine hydrochloride.
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- Method of producing α-L-aspartyl-L-phenylalanine methylester
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A method for preparing an α-L-aspartyl-L-phenylalanine alkyl ester, which method comprises: reacting a divalent alkali salt of aspartic acid, having an amino-protective group, with an organic halo ester compound, to form a monovalent, alkali-salt, mixed,anhydride aspartate compound; and condensing the mixed,anhydride aspartate compound with an alkyl ester of L-phenylalanine under alkaline conditions and reducing the pH to an acidic condition after condensation to free the amino and carboxyl groups, to form a mixture consisting essentially of the alpha and beta alkyl ester of α-L-aspartyl-L-phenylalanine.
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- Process for the preparation of L-aspartic acid N-thiocarboxyanhydride
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An improved process for the preparation of L-aspartic acid N-thiocarboxyanhydride by the reaction of a 0.75 to 1.25 molar solution of an N-alkoxy-thiocarbonyl L-aspartic acid in a lower alkyl acetate solvent with a phosphorous trihalide. The desired product is substantially insoluble in the lower alkyl acetate solvent and is recovered in pure form without further purification or separation steps.
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- Purification of L-aspartyl-L-phenylalanine alkyl esters
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L-Aspartyl-L-phenylalanine alkyl esters prepared by the reaction of L-aspartic acid N-thiocarboxyanhydride and an appropriate L-phenylalanyl alkyl ester are deodorized by contacting the L-aspartyl-L-phenylalanine alkyl ester in aqueous solution with an effective amount of an alkali metal periodate.
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- Addition compound of dipeptide derivative and amino acid derivative
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Addition compounds having the formula STR1 wherein R1 represents an aliphatic oxycarbonyl group, benzyloxycarbonyl group which can have nuclear substituents, or benzoyl, aromatic sulfonyl or aromatic sulfinyl group; R2 represents methyl, isopropyl, isobutyl, isoamyl or benzyl group; R3 represents a lower alkoxyl, benzyloxy or benzhydryloxy group and n represents 1 or 2 together with methods for preparing (I) and for decomposing (I) into the constituent dipeptide esters and amino acid esters.
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- Method of removing formyl groups from N-formyl-amino acid and N-formyl-peptide esters having free carboxyl groups
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The masking N-formyl group of an N-formyl-amino acid ester or an N-formyl-peptide ester having a free carboxyl group is removed without major side reactions when the ester is contacted with a strong acid in a mixture of water and a specific organic solvent such as methyl ethyl ketone or acetonitrile. This method is specifically applicable to the production of L-aspartyl amino acid lower alkyl esters which are known as low calorie sweeteners.
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- Method of removing formyl groups from N-formyl-amino acid and N-formyl-peptide esters
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The masking N-formyl group of an N-formyl-amino acid ester or N-formyl-peptide ester is removed without major side reactions when the ester is reacted in an inert liquid medium with hydroxylamine of which at least 70% is present in the form of a salt with a strong acid, the remainder, if any, being present as the free base or the salt of a weak acid.
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- Process for isolation of aspartyl dipeptide esters
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The isolation of certain dipeptide esters, known to be potent sweetening agents, is achieved by selectively extracting, with a suitable alkanol in a heterogeneous system, an aqueous solution containing the dipeptide ester together with a variety of impurities.
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- Method of producing α-L-aspartyl-L-phenylalanine lower alkyl esters
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When hydrogen halide salts of L-aspartic anhydride are reacted with lower alkyl esters of L-phenylalanine to produce the corresponding L-aspartyl-L-phenylalanine esters, a significant increase in yield and in the proportion of the α-isomer to the β-isomer is achieved when the reaction is carried out in the presence of a lower alkanol and of a strong acid, such as sulfuric acid, hydrogen chloride, or mono-esters of sulfuric acid with a lower alkanol.
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- N-protected-α-amino acid compounds
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Novel N-protected-α-amino acid compounds are disclosed in which the amino functionality is protected by a 1-methylcyclobutyloxycarbonyl or 1-methylcyclohexyloxycarbonyl. Processes for the synthesis of amino acids containing these protecting groups and the use of these novel amino acid compounds in the preparation of peptides are also disclosed.
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- Process for the preparation of α-L-aspartyl-L-phenylalanine alkyl esters
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A process for the preparation of α-L-aspartyl-L-phenylalanine alkyl esters wherein L-phenylalanine is reacted with N-protected-L-aspartic anhydride, the resulting product is treated to yield α-L-aspartyl-L-phenylalanine which is esterified with an alkanol to yield an α-L-aspartyl-L-phenylalanine alkyl ester which is recovered. Novel precursors for α-L-aspartyl-L-phenylalanine alkyl esters are prepared in the process of this invention.
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