Glutamic y-methyl ester

Procedures A and B illustrate the two current methods for preparation of N-9-phenylfluoren-9-yl derivatives of amino acids and amino acid esters. Free carboxylate (as in alanine in Step A) or free hydroxyl (e.g., serine7) functions can be blocked for the duration of the reaction as trimethylsilyl (TMS) esters or ethers, respectively, by treatment with chlorotrimethylsilane and triethylamine. The TMS group(s) are then removed by methanolysls from carboxylic acids (as in Step A) and mild acidic hydrolysis from hydroxyl groups, both being accomplished during product isolation. In addition to 2, the N-9-phenylfluoren-9-yl derivatives of serine,7 glutamic add y-methyl ester,8 and aspartic acid 3-methyl ester3 9 have been prepared in this manner. 

Enantioselective Michael addition of glycine derivatives by means of chiral phase-transfer catalysis has been developed to synthesize various functionalized a-alkyl-a-amino acids. Corey utilized 4d as catalyst for asymmetric Michael addition of glycinate Schiff base 1 to a,(3-unsaturated carbonyl substrates with high enantioselectivity (Scheme 2.15) [35,36]. With methyl acrylate as an acceptor, the a-tert-butyl-y-methyl ester of (S)-glutamic acid can be produced, a functionalized glutamic acid... 

Side-chain modifications glutamate y-carboxyl glutamyl y-methyl ester cytochrome c-557 bacterial chemotactic receptors... 

Azotomycin is anticancer antibiotic produced by Streptomyces ambofaciens. Total sythesis of it from y-benzyl-N-tert-butyloxycarbonyl-L-glutamic acid (y-OBzi-N-Boc-L-Glu) has been accomplished in nine steps. The mixed carbonic anhydride method was chosen for peptide bond formation. Commerically available y-OBzi-N-Boc-L-Glu was esterified with ethereal diazomethane, deprotected with trifluoroacetic acid-methylene chloride (1 1), and converted to hydrochloride y-benzyl-L-glutamic acid a-methyl ester (y-OBzi-L-Glu-a-OMe HCI) by treatment with dry hydrogen chloride in ethyl ether, MP 129°-135°C (dec.) [a]D25= + 13.3° (CHCI3). 

For the synthesis of the AMT ester (VIII.151), bromide (VIII. 156)-HBr was condensed in situ with 4-aminobenzoic acid and the product, 4-amino-4-deoxypteroic acid (APA), was treated directly with a mixture of formic and acetic acid to obtain the W °-formyl derivative (FmAPA, 65% yield) [292]. Condensation of FmAPA with y-r-butyl a-methyl L-glutamate to form the diester (VIII. 155) was accomplished in 82% yield by a modified mixed anhydride procedure involving four cycles of in situ carboxyl group reactivation. Hydrolysis of the methyl ester and W -formyl group at the same time with NaOH proved impossible as a result of an unforeseen loss of the y-t-butyl ester. When the a-methyl ester was first removed under mild conditions with Ba(0H)2, however, the relatively stable V -formyl derivative (VIII.154) was isolated satisfactorily in 79% yield. Subsequent cleavage of the W -formyl group was then accomplished by carefully controlled hydrolysis in 0.25 M NaOH (1.75 h at 25 °C). In an alternative synthesis, FmAPA was activated by reaction with bis(4-nitrophenyl) carbonate to obtain the corresponding... 

Pentafluorophenyl esters, obtained from pentafluorophenol and amino-acids protected with t-butoxycarbonyl groups, are formed without racemization of the amino-acid residue and are useful in peptide synthesis. Similarly useful is the fact that the pentafluorophenyl esters of JV-benzoxycarbonyl-y-methyl-L-glutamic acid and iV-benzoxycarbonyl-jS-methyl-L-aspartic acid show a particularly high ratio of the rate constants for coupling with L-valine methyl ester v. racemization in the presence of triethylamine. The reaction of S-(2,4-difluorophenyl)saIi( lic acid with alkyl chloroformates gives the esters (93 R = Et or Bu), which are claimed to... 

In order to activate or enhance the activity of group III of the metabotropic glutamate receptors, new and potent phosphinic agonists were synthesized by Acher et al. in 2007 [54], Indeed, these presynaptic receptors inhibit the adenylate cyclase and the release process. y-Phosphinic acid derivative 49 is the key intermediate for the formation of compounds 51,52 and 53 (Scheme 7). Starting from a radical addition of hypophosphorous acid to the IV-CBz protected vinylglycine methyl ester 48, the phosphinic derivative compound 49 was obtained in 94%... 

Synonyms Glutamic acid, 5-methyl ester, homopolymer Poly-y-methyl glutamate Poly-y-methyl L-glutamate... 

The reactivity of the compounds to be derivatized clearly plays an equally important part. Thus, for example, ephedrine, pseudoephedrine and analogues were acylated with TFAA for 5 minutes at 60 "C [57], tricyclic antidepressants with HFBA for 10 minutes at 60 °C [58], the methyl esters of pipecolic acid, proline, glutamic acid and y-aminobutyric acid with HFBA for 20 minutes at 150 °C [59], and catecholamines (after methylation of the j8-hydroxyl) with PFPA for 15 minutes at 80 °C [60]. 

Copper(II) complexes of the Schiff bases derived for salicylaldehyde and dibenzyl asparate or glutamate have recently been characterized.497 Refluxing these complexes in methanol for 30 min gives bis(a-methyl-/3-benzyl-N-salicylideneaspartato)copper(II) in which selective ester and bis(a-methyl-y-benzyl-N-salicylideneglutamato)copper(II) exchange occurs. A similar selective ester exchange reaction has also been observed with the copper(II) complex of the Schiff base derived from salicylaldehyde and dibenzyl dl-asparate.498... 

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