66449-90-9Relevant academic research and scientific papers
Synthesis and neuroprotective activity of analogues of glycyl-L-prolyl-L- glutamic acid (GPE) modified at the α-carboxylic acid
Trotter, Nicholas S.,Brimble, Margaret A.,Harris, Paul W.R.,Callis, David J.,Sieg, Frank
, p. 501 - 517 (2007/10/03)
The synthesis of nine GPE* analogues, wherein the α-carboxylic acid group of glutamic acid has been modified, is described by coupling readily accessible N-benzyloxycarbonyl-glycyl-l-proline 2 with various analogues of glutamic acid. Pharmacological evaluation of the novel compounds was undertaken to further understand the role of the glutamate residue on the observed neuroprotective properties of the endogenous tripeptide GPE.
Synthesis of fused 1,2,5-triazepine-1,5-diones and some N2- and N3-substituted derivatives: Potential conformational mimetics for cis-peptidyl prolinamides
Lenman, Morag M.,Lewis, Arwel,Gani, David
, p. 2297 - 2311 (2007/10/03)
The synthesis of a new fused 1,2,5-triazepine-1,5-dione heterocycle, which is expected to mimic structural features of cis-peptldyl prolinamides, is described. The required parent heterocycle, corresponding to cis-glycy-(2S)-prolinamide, has been prepared in good yield by the cyclisation of N-(2-bromoacetylprolyl)-hydrazine which is itself generated in situ from the bromoacetyl proline methyl ester. Analogues corresponding to cis-(2R)-alanyl- and cis-(2S)-alanyl-(2S)-prolinamide have been similarly prepared from the appropriate N-(2-bromopropionyl)proline methyl esters and hydrazine hydrate where the cyclisation step, involving the displacement of bromide, has been shown to occur with inversion of configuration at C-2 of the propionyl moiety. Acylation at the N-3 position of the triazepine is equivalent to N-terminal acylation of the residue preceding the proline residue in cis-aminoacyl prolinamides. This has been achieved without incident using standard peptide coupling procedures. Extension at the 'C-terminal' has been achieved by preparing elaborated hydrazine precursors which are reacted with suitably activated esters of N-α-halogenoacylprolines, prior to cyclisation, to give the required fused triazepine dione. Thus it is possible to prepare constrained cis-peptidyl prolyl peptide mimetics of defined stereochemistry based upon this new triazepine dione in which all of the non-proline residues can be varied.
(2-cyano-2-oximinoacetyl)-amino acid derivatives
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, (2008/06/13)
Novel fungicidally active compounds of the formula STR1 in which R represents alkyl, cyanoalkyl or in each case optionally substituted alkenyl, alkinyl, cycloalkyl, cycloalkylalkyl or phenylalkyl, R1 represents the --OR2 or --NR3 R4 groups, and R3 and R4 have special special definitions.
Peptide Synthesis with Benzo- and Naphthosultones
Acher, Francine,Wakselman, Michel
, p. 4133 - 4138 (2007/10/02)
6-Nitro- and 6,8-dinitronaphth-1,2-oxathiole S,S-dioxides (7b and 7c) have been prepared from the parent naphthosultone 7a and compared with 5-nitrobenz-3H-1,2-oxathiole S,S-dioxide (1b) as coupling reagents for peptide synthesis.Nucleophilic attack of a carboxylate salt on these strained five-membered sultones leads to activated esters 3 and 9 which rapidly react with amines (except in the case of 9c).The rate constant for the formation of ester 9b is higher than that of 3b.Amides or peptides are formed in slightly better yields with the naphthosultone 7b than with the benzosultone 1b.The naphthosultones are also preferred over the benzosultones from the point of view of amount of 5(4H)-oxazolone formation from N-benzoyl amino acids and the degree of racemization.However the rate of alkaline hydrolysis of 7b is slower than that of 1b.All these results may be rationalized by a better intramolecular acyl transfer reaction in the more rigid mixed anhydride intermediate 8b.There is no dependence on in the rate equation for aminolysis of esters 3b and 9b by benzylamine in THF, acetonitrile, or DMF and the aminolysis is probably anchimerically assisted by a neighbouring S=O group.Esters 3b are more selective acylating agents for primary amino groups in the presence of secondary ones than esters 9b and this observation is exploited in a synthesis of maytenine by selective acylation of spermidine.
