Side Chain Methyl Substitution in the δ-Opioid Receptor Antagonist TIPP Has an Important Effect on the Activity Profile
摘要:
The delta-opioid antagonist H-Tyr-Tic-Phe-Phe-OH (TIPP-OH) or its C-terminal amide analogue was systematically modified topologically by substitution of each amino acid residue by all stereoisomers of the corresponding beta-methyl amino acid. The potency and selectivity (delta- vs mu- and kappa-opioid receptor) were evaluated by radioreceptor binding assays. Agonist or antagonist potency were assayed in the mouse vas deferens and in the guinea pig ileum. In the TIPP analogues containing L-beta-methyl amino acids the influence on delta-receptor affinity and on delta-antagonist potency is limited, the [(2S,3R)-beta-MePhe(3)]TIPP-OH analogue being among the most potent delta-antagonists reported. In the D-beta-methyl amino acid series, the [D-beta-MeTic(2)] analogues are delta-selective antagonists whereas [D-Tic(2)]TIPP-NH2 is a delta-agonist. NMR studies did not indicate any influence of the beta-methyl substituent on the conformation of the Tic residue. The [(2R,3S)-beta-MePhe(3)]TIPP-NH2 is a potent delta-agonist, its C-terminal carboxylic acid analogue being more delta-selective but displaying partial agonism in both the delta- and mu-bioassay. These results constitute further examples of a profound influence of beta-methyl substitution on the potency, selectivity, and signal transduction properties of a peptide.
Efficient method for the total asymmetric synthesis of the isomers of .beta.-methyltyrosine
摘要:
Alpha-Amino acids modified at the beta-carbon atom can provide topographical constraints when incorporated into a peptide. Such modifications can modulate the physical, chemical, and biological properties of the compound. In order to properly evaluate the effect of such modifications, large-scale asymmetric syntheses of the isomers are needed. A method for the stereoselective large-scale synthesis of an four stereoisomers of beta-methyltyrosine is described in this paper. The stereochemistry of both the alpha- and beta-stereocenters was set using 4-phenyl-2-oxazolidinone as a chiral auxiliary. The key reactions were an asymmetric Michael-like addition of an organocuprate to a chiral alpha,beta-unsaturated acyloxazolidinone (beta center) and subsequent stereoselective electrophilic bromination of the resulting product (alpha center). Conversion of the bromide to the azide, catalyzed hydrolysis to the azido acid with simultaneous recovery of the chiral auxiliary, reduction of the azide, and final deprotection of the phenol group afforded the desired amino acids. In general, the reactions were performed in yields over 80 %, and the isomers were obtained in enantiomeric purities of 98:2 to 99:1.
Synthesis of (2S,3R)-β-methyltyrosine catalyzed by tyrosine phenol-lyase
作者:Kyonghee Kim、Philip A. Cole
DOI:10.1016/s0960-894x(99)00162-6
日期:1999.4
A one-step enzymatic synthesis of the conformationally restrained tyrosine analog (2S, 3R)-beta-methyltyrosine is reported. This synthesis extends the preparative chemistry associated with tyrosine phenollyase. This beta-methyltyrosine derivative was shown to be an efficient protein tyrosine kinase substrate, suggesting that conformational restraint may ultimately be used to enhance tyrosine kinase recognition of substrates. (C) 1999 Elsevier Science Ltd. All rights reserved.
Side Chain Methyl Substitution in the δ-Opioid Receptor Antagonist TIPP Has an Important Effect on the Activity Profile
作者:Dirk Tourwé、Els Mannekens、Trang Nguyen Thi Diem、Patricia Verheyden、Hendrika Jaspers、Géza Tóth、Antal Péter、István Kertész、Gabriella Török、Nga N. Chung、Peter W. Schiller
DOI:10.1021/jm981011u
日期:1998.12.1
The delta-opioid antagonist H-Tyr-Tic-Phe-Phe-OH (TIPP-OH) or its C-terminal amide analogue was systematically modified topologically by substitution of each amino acid residue by all stereoisomers of the corresponding beta-methyl amino acid. The potency and selectivity (delta- vs mu- and kappa-opioid receptor) were evaluated by radioreceptor binding assays. Agonist or antagonist potency were assayed in the mouse vas deferens and in the guinea pig ileum. In the TIPP analogues containing L-beta-methyl amino acids the influence on delta-receptor affinity and on delta-antagonist potency is limited, the [(2S,3R)-beta-MePhe(3)]TIPP-OH analogue being among the most potent delta-antagonists reported. In the D-beta-methyl amino acid series, the [D-beta-MeTic(2)] analogues are delta-selective antagonists whereas [D-Tic(2)]TIPP-NH2 is a delta-agonist. NMR studies did not indicate any influence of the beta-methyl substituent on the conformation of the Tic residue. The [(2R,3S)-beta-MePhe(3)]TIPP-NH2 is a potent delta-agonist, its C-terminal carboxylic acid analogue being more delta-selective but displaying partial agonism in both the delta- and mu-bioassay. These results constitute further examples of a profound influence of beta-methyl substitution on the potency, selectivity, and signal transduction properties of a peptide.
Efficient method for the total asymmetric synthesis of the isomers of .beta.-methyltyrosine
作者:Ernesto Nicolas、K. C. Russell、J. Knollenberg、Victor J. Hruby
DOI:10.1021/jo00078a042
日期:1993.12
Alpha-Amino acids modified at the beta-carbon atom can provide topographical constraints when incorporated into a peptide. Such modifications can modulate the physical, chemical, and biological properties of the compound. In order to properly evaluate the effect of such modifications, large-scale asymmetric syntheses of the isomers are needed. A method for the stereoselective large-scale synthesis of an four stereoisomers of beta-methyltyrosine is described in this paper. The stereochemistry of both the alpha- and beta-stereocenters was set using 4-phenyl-2-oxazolidinone as a chiral auxiliary. The key reactions were an asymmetric Michael-like addition of an organocuprate to a chiral alpha,beta-unsaturated acyloxazolidinone (beta center) and subsequent stereoselective electrophilic bromination of the resulting product (alpha center). Conversion of the bromide to the azide, catalyzed hydrolysis to the azido acid with simultaneous recovery of the chiral auxiliary, reduction of the azide, and final deprotection of the phenol group afforded the desired amino acids. In general, the reactions were performed in yields over 80 %, and the isomers were obtained in enantiomeric purities of 98:2 to 99:1.