- Divergent and site-selective solid-phase synthesis of sulfopeptides
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On solid ground: A solid-phase strategy for the efficient synthesis of sulfopeptides is described. Selective deprotection of orthogonally-protected tyrosine residues and solid-phase sulfation provided divergent access to differentially sulfated peptides in high yields. Copyright
- Taleski, Deni,Butler, Stephen J.,Stone, Martin J.,Payne, Richard J.
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- Macrocyclic analogues of the diuretic insect neuropeptide helicokinin I show strong receptor-binding
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Abstract Helicokinin I, a diuretic neuropeptide of the relevant cotton pest Helicoverpa zea represents a promising target for the design of insect neuropeptide mimetics. Using a ring-closing metathesis reaction, N-terminal bridged macrocyclic helicokinin
- Tran Van, Chien,Nennstiel, Dirk,Scherkenbeck, Jürgen
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- Chiral Lewis acids supported on silica gel and alumina, and their use as catalysts in Diels-Alder reactions of methacrolein and bromoacrolein
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Several derivatives of (S)-tyrosine are supported on silica gel through the phenolic oxygen atom. The Lewis acids obtained by treatment of these solids with BH3 are able to promote the reactions of methacrolein and bromoacrolein with cyclopenta
- Fraile, Jose M.,Garcia, Jose I.,Mayoral, Jose A.,Royo, Ana J.
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- Polymer Attached Cyclic Dipeptides as Catalysts for Enantioselective Cyanohydrin Formation
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Derivatives of cyclo-, related to the "Inoue" catalyst, cyclo- have been attached to chloromethylated polystyrene and to polysiloxane polymers via spacer groups coupled to the tyrosine phenolic residue.These polymer-attac
- Kim, Hyun J.,Jackson, W. Roy
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- Design and synthesis of β-strand-fixed peptides inhibiting aggregation of amyloid β-protein
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Aggregation of 42-residue amyloid β-protein (Aβ42) can be prevented by β-sheet breaker peptides (BSBps) homologous to LVFFA residues, which are included in a β-sheet region of Aβ42 aggregates. To enhance the affinity of BSBps to the Aβ42 aggregates, we de
- Akagi, Ken-ichi,Masuda, Yuichi,Monobe, Yoko,Shibata, Kana,Tanaka, Fumiya
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supporting information
(2020/08/07)
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- Total Synthesis of the Putative Structure of Asperipin-2a and Stereochemical Reassignment
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The total synthesis of the putative structure of asperipin-2a is described. The synthesis features ether cross-links between the phenolic oxygen of Tyr6 and the β position of Tyr3 and the phenolic oxygen of Tyr3 and the β position of Hpp1 in the unique 17- and 14-membered bicyclic structure of asperipin-2a, respectively. The synthesized putative structure does not match the natural product, and a stereochemical reassignment is postulated.
- Hutton, Craig A.,Shabani, Sadegh,White, Jonathan M.
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supporting information
p. 7730 - 7734
(2020/10/09)
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- Novel non-peptide GPIIb/IIIa antagonists: Synthesis and biological activities of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2- oxoethyl)-2-oxopiperazinyl] acetic acids
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To improve the in vitro and in vivo potency of our first low molecular weight GPIIb/IIIa antagonist 1 (TAK-029), a series of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2- oxoethyl)-2-oxopiperazinyl]acetic acids were synthesized th
- Kitamura,Fukushi,Miyawaki,Kawamura,Terashita,Sugihara,Naka
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p. 258 - 267
(2007/10/03)
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- A4 B6 macrotricyclic enantioselective receptors for amino acid derivatives, and other compounds
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The subject invention provides chiral receptor molecules having the structure: STR1 wherein A has the structure: STR2 and R1 and R2 are independently the same or different and are H, F, alkyl, aryl, etc.; X is CH2 or NH; Y is C=O or SO2 ; and n is 0 to about 3; which are useful for the purification of enantiomers of amino acid derivatives and other compounds. The subject invention also provides methods of preparing said receptor molecules.
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- Enantioselective receptor for amino acid derivatives, and other compounds
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The present invention relates to a composition having the general formula: STR1 wherein each of A, B, C, X, Y, and Z is independently O, NH, N(CH2)m CH3 ], N(C=O) (CH2)m CH3 ], CH2, S, or Se; each of R1, R2, and R3 is independently phenyl, 4-hydroxyphenyl, pyridyl, pyrrolyl, indolyl, naphthyl, thiophenyl, (C=O) (CH2)p CH3, NH(C=O) (CH2)p CH3 ], OH, COOH, NH2, or SH; and m, n, and p are integers between 0 and 5. The composition is a chiral receptor molecule useful for the purification of enantiomers of derivatives of amino acids and of compounds able to form hydrogen bonds. The preparation of the composition involves coupling a trifunctional aromatic molecule with three protected chiral molecules at the three aromatic groups, cleaving protecting groups, and joining adjacent chiral groups by multiple lactamizations. The receptor may be used in a form either bound to a solid support or dissolved in an immiscible phase to effect convenient purification of enantiomers or other compounds of interest.
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- Reductive deprotection of aryl allyl ethers with Pd(Ph3)4/NaBH4
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Treatment of aryl allyl ethers with catalytic amounts of Pd(PPh3)4 and NaBH4 at room temperature afforded the parent phenol in high yield under non-hydrolytic conditions.
- Beugelmans, Rene,Bourdet, Sebastien,Bigot, Antony,Zhu, Jieping
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p. 4349 - 4350
(2007/10/02)
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- O'-(epoxyalkyl)tyrosines and (epoxyalkyl)phenylalanine as irreversible inactivators of serine proteases: Synthesis and inhibition mechanism
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A series of O'-(epoxyalkyl)tyrosines and a carboxy terminal (epoxyalkyl)tyrosine and -phenylalanine were synthesized as potential serine protease inhibitors. N-Acetyl derivatives showed irreversible inactivation vis-a-vis subtilisin, while the N-benzoyl ones were specific toward chymotrypsin. The most potent inactivation of chymotrypsin was achieved by a O'-(3,4-epoxybutyl)-L-tyrosine derivative. The inactivation was shown to be stereospecific since a D derivative led to no irreversible inactivation. Placement of the epoxyalkyl group at the carboxy terminus led to potent rapid inactivation. Under these conditions some of the activity was later recovered. The two classes of inactivators (O'-epoxyalkyl and carboxy-epoxyalkyl) appear to operate by different mechanisms. Most importantly, it was found that irreversible inactivation by O'-(epoxyalkyl)-L-tyrosine only resulted if the carboxy terminus was a substrate (i.e. a compound with free carboxy terminus did not lead to inactivation). The ultimate activity kinetic assay (Daniels, S.B.; et al. J. Biol. Chem. 1983, 258, 15046-15053.) indicated that the epoxyalkyl group on the phenolic oxygen had an optimal length of four carbons with respect to the turnover ratio (the ratio of molecules undergoing turnover compared to those that inactivate the enzyme) for chymotrypsin. A different kinetic assay (Ashani, Y.; Wins P.; Wilson, I.B. Biochim. Biophys. Acta 1972, 284, 427-434.) demonstrated that substratelike turnover was proceeding at considerably slower rates than for the corresponding true substrates and with rate-limiting deacylation of the acyl-enzyme. Amino acid analysis subsequent to acid hydrolysis demonstrated that Met had been selectively alkylated by the O'-(epoxyalkyl)tyrosine derivative. By contrast, α-chymotrypsin inactivated with N-benzoyl-L-Phe-2,3-epoxypropyl ester then subjected to amino acid analysis showed no change in the content of any amino acid that would serve as a potential nucleophile to the inhibitor. Yet, the L-Phe content increased, indicating that a covalent bond had been formed between the inhibitor and the enzyme. Either the bond between the inhibitor and the enzyme did not withstand the hydrolytic conditions and/or there was less than 10% decrease in the amino acids with nucleophilic side chains upon inactivation. Finally, two tripeptides containing O'-(epoxyalkyl)-L-tyrosines were synthesized [N-(tert-butoxycarbonyl)-L-alanyl-L-alanyl-O'-(2,3-epoxypropyl)-L-tyro sine ethyl ester and N-(trifluoroacteyl)-L-valyl-O'(2,3-epoxypropyl)-L-tyrosyl-L-valine methyl ester] as potential elastase inhibitors and were found to reversibly and competitively inhibit porcine pancreatic elastase.
- Tous,Bush,Tous,Jordan
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p. 1620 - 1634
(2007/10/02)
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