- Microwave-assisted solution phase peptide synthesis in neat water
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An environmentally benign protocol for solution phase peptide synthesis has been developed in neat water using TBTU/HOBt/DIEA as a coupling combination under microwave irradiation. Key features of this procedure are the replacement of commonly used toxic organic solvents like DMF and NMP, the use of lower amounts of reactants, compatibility with both N-α-Boc- and N-α-Fmoc-protected amino acids and all commonly used side-chain protective groups, short reaction time, and racemization-free synthesis in high yield and purity. The Royal Society of Chemistry 2013.
- Mahindra, Amit,Nooney, Karthik,Uraon, Shrikant,Sharma, Krishna K.,Jain, Rahul
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p. 16810 - 16816
(2013/09/23)
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- Process for the preparation of azacycloalkylakanoyl pseudotetrapeptides
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This invention is directed to a process for preparing a pseudotetrapeptide of formula I or a salt or prodrug thereof wherein is optionally nitrogen protected azaheterocyclyl; is a single or double bond; q is 1-5; B is alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, alkylcycloalkylalkyl, aryl, aralkyl, alkylaryl, or alkylaralkyl; Q2 is H or a carboxylic acid protecting group; J is —H, alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, alkylcycloalkylalkyl, aryl, substituted aryl, aralkyl, substituted aralkyl; L is OR1, or NR1R2, where R1 and R2 are independently —H, alkyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, alkylcycloalkylalkyl, aryl, aralkyl, alkylaryl or alkylaralkyl; and p is 1 or 2 which comprises the coupling of two dipeptides or psuedopeptides.
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- Development of peptide 3D structure mimetics: Rational design of novel peptoid cholecystokinin receptor antagonists
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The two hormones cholecystokinin and gastrin share the same C-terminal sequence of amino acids, namely Gly29-Trp30-Met31-Asp32-Phe33-NH2. Nevertheless, this congruence has not precluded usi
- Low,Black,Broughton,Buck,Davies,Dunstone,Hull,Kalindjian,McDonald,Pether,Shankley,Steel
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p. 3505 - 3517
(2007/10/03)
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- Minor structural differences in Boc-CCK-4 derivatives dictate affinity and selectivity for CCK-A and CCK-B reeeptors
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We previously reported novel Boc-CCK-4 (Boc-Trp-Met-Asp-Phe-NH2) derivatives possessing the general structure Boc-Trp-Lys[Nε-CO-NH-(R-Ph)]- Asp-Phe-NH2 (Shiosaki et al. J. Med. Chem. 1991, 34, 2837-2842). In contrast to Boc-CCK-4, wh
- Shiosaki,Chun Wel Lin,Kopecka,Bianchi,Miller,Stashko,Witte
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p. 1169 - 1172
(2007/10/03)
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- CCK-B agonist or antagonist activities of structurally hindered and peptidase-resistant Boc-CCK4 derivatives
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Replacement of Met31 by (N-Me)Nle in CCK8 or CCK4 has been shown to improve the affinity and selectivity for CCK-B receptors. In order to obtain molecules with enhanced bioavailability, two novel series of protected tetrapeptides of the general formula Boc-Trp30-X-Asp-Y33 have been developed. Introduction of (N-Me)Nle and the bulky, aromatic naphthylalaninamide (Nal-NH2) in positions X and Y, respectively, does not greatly modify the affinity for guinea pig brain CCK-B receptors. In contrast, incorporation of hindering N-methyl amino acids such as (N-Me)Phe, (N-Me)Phg, or (N-Me)Chg, but not their non-methylated counterparts, in position X induced a large decrease in affinity for the CCK-B binding sites. Among the various peptides synthesized, Boc-[(N-Me)Nle31,1Nal- NH233]CCK4 (2) (K(I) = 2.8 nM), Boc-[Phg31,1Nal-NH233]CCK4 (15) (K(I) = 14 nM), and Boc-[Phg31,1Nal-N(CH3)233]CCK4 (17) (K(I) = 39 nM) displayed good affinities for brain CCK-B receptors and had good selectivity ratios. These pseudopeptides, in which the presence of unnatural and hydrophobic residues is expected to improve their penetration of the central nervous system, were shown to be very resistant to brain peptidases. Interestingly, whereas compounds 2 and 15 proved to be full agonists for rat hippocampal CCK-B receptors when measured in an electrophysiological assay, compound 17 behaved as a potent antagonist in the same test and displayed a good affinity in rat brain K(I)(CCK-B) = 51 nM as compared to the Merck antagonist L365,260, K(I)(CCK-B) = 12 nM. This illustrates a simple means to obtain CCK-B antagonists and suggests that the free, CONH2 group plays a critical role in the recognition of the agonist state of brain CCK-B receptors.
- Corringer,Weng,Ducos,Durieux,Boudeau,Bohme,Roques
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p. 166 - 172
(2007/10/02)
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- Boc-CCK-4 derivatives containing side-chain ureas as potent and selective CCK-A receptor agonists
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Novel Boc-CCK-4 derivatives were communicated recently as having high potency and selectivity for the CCK-A receptor (Shiosaki et al. J. Med. Chem. 1990, 33, 2950-2952). While Boc-CCK-4 binds selectively to the CCK-B receptor, replacement of the methionin
- Shiosaki,Lin,Kopecka,Tufano,Bianchi,Miller,Witte,Nadzan
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p. 2837 - 2842
(2007/10/02)
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- Boc-Trp-Orn(Z)-Asp-NH2 and derivatives: A new family of CCK antagonists
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The respective roles of the benzyloxycarbonyl group (Z) and of the N-terminal tripeptide moiety in the antagonist properties of the cholecystokinin CCK8 analogue Boc-[Nle28,Orn(Z)31]CCK27-33 (Marseigne et al. J.
- Gonzalez-Muniz,Bergeron,Marseigne,Durieux,Roques
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p. 3199 - 3204
(2007/10/02)
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- Synthesis and biological activities of some pseudo-peptide analogues of tetragastrin: The importance of the peptide backbone
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Pseudo-peptide analogues of the C-terminal tetrapeptide of gastrin, in which a peptide bond has been replaced by a CH2-NH bond, i.e. (tert-butyloxycarbonyl)-L-tryptophyl-Ψ(CH2-NH)-L-leucyl-L-aspartyl-L-phenylalanine amide (8), (tert-
- Martinez,Bali,Rodriguez,Castro,Magous,Laur,Lignon
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p. 1874 - 1879
(2007/10/02)
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- Effect of Piperidine on Benzylaspartyl Peptides in Solution and in the Solid Phase
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Basic conditions (e.g. piperidinolysis), used for the removal of the Nα-9-fluorenylmethyloxycarbonyl group, lead to significant cleavage of side-chain benzyl esters of peptides containing benzylaspartyl residues both in solution and solid-phase syntheses, the intermediate imide derivative is slowly transformed to a mixture of piperidides.
- Schoen, Istvan,Colombo, Roberto,Csehi, Attila
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p. 505 - 507
(2007/10/02)
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