- Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
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The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.
- Yen, Andy,Pham, Anh Hoang,Larin, Egor M.,Lautens, Mark
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supporting information
p. 7549 - 7553
(2019/10/02)
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- Synthesis, in vitro antimicrobial, antioxidant, and antidiabetic activities of thiazolidine–quinoxaline derivatives with amino acid side chains
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Abstract: A novel protocol for the rapid assembly of a hybrid framework based on amino acid, thiazolidine and quinoxaline scaffolds has been demonstrated by microwave irradiation. The quinoxalines with amino acid side chains 5a–5c were prepared in three steps from 2,4-dinitrofluorobenzene and the amino acids, valine, methionine, and tyrosine and subsequently reacted with four different aldehydes and thioglycolic acid to produce thiazolidine–quinoxaline hybrids with amino acid side chains 6a–6l. All synthesized compounds were evaluated for their in vitro antimicrobial, antioxidant, and antidiabetic activities. Compounds 6f, 6j, and 6k showed broad spectrum antimicrobial activity against Gram +ve and Gram –ve bacteria, whilst 6h, 6k, and 6l showed the best antioxidant activity in the same order of magnitude to that of ascorbic acid. Four of the compounds, 5c, 6d, 6g, and 6k showed activity against α-glucosidase and α-amylase similar to acarbose. Those compounds showing antibacterial activity possessed 4-fluorophenyl and 4-methoxyphenyl groups along with methionine and tyrosine side chains while the compounds showing antioxidant, α-glucosidase, and α-amylase activity contained 4-nitrophenyl and 4-methoxyphenyl groups on the thiazolidine moiety with mainly methionine and tyrosine side chains. The α-glucosidase and α-amylase inhibitory compound 5c did not have a thiazolidine moiety and 6d was the only active compound with a valine amino acid side chain. Compound 6k with a tyrosine side chain and a 4-methoxyphenylthiazolidine moiety on the quinoxaline scaffold showed good bioactivity in all three assays.
- Shintre, Suhas A.,Ramjugernath, Deresh,Islam, Md Shahidul,Mopuri, Ramgopal,Mocktar, Chunderika,Koorbanally, Neil A.
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p. 2141 - 2151
(2017/08/03)
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- NOVEL HDAC INHIBITORS AND METHODS OF TREATMENT USING THE SAME
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Disclosed herein are novel HDAC inhibitors. The HDAC inhibitors may be used in methods of treating cancer. The HDAC inhibitors may be used in methods of treating a neurological disorder.
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Paragraph 000188
(2017/03/21)
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- Amino acid conjugates of lithocholic acid as antagonists of the EphA2 receptor
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The Eph receptor-ephrin system is an emerging target for the development of novel antiangiogenetic agents. We recently identified lithocholic acid (LCA) as a small molecule able to block EphA2-dependent signals in cancer cells, suggesting that its (5β)-cholan-24-oic acid scaffold can be used as a template to design a new generation of improved EphA2 antagonists. Here, we report the design and synthesis of an extended set of LCA derivatives obtained by conjugation of its carboxyl group with different α-amino acids. Structure-activity relationships indicate that the presence of a lipophilic amino acid side chain is fundamental to achieve good potencies. The l-Trp derivative (20, PCM126) was the most potent antagonist of the series disrupting EphA2-ephrinA1 interaction and blocking EphA2 phosphorylation in prostate cancer cells at low μM concentrations, thus being significantly more potent than LCA. Compound 20 is among the most potent small-molecule antagonists of the EphA2 receptor.
- Incerti, Matteo,Tognolini, Massimiliano,Russo, Simonetta,Pala, Daniele,Giorgio, Carmine,Hassan-Mohamed, Iftiin,Noberini, Roberta,Pasquale, Elena B.,Vicini, Paola,Piersanti, Silvia,Rivara, Silvia,Barocelli, Elisabetta,Mor, Marco,Lodola, Alessio
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supporting information
p. 2936 - 2947
(2013/05/22)
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- DIPEPTIDES AS FEED ADDITIVES
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The invention relates to feed additives containing dipeptides or salts thereof, in which one amino acid residue of the dipeptide is a DL-methionyl residue and the other amino acid residue of the dipeptide is an amino acid in the L-configuration selected from lysine, threonine, tryptophan, histidine, valine, leucine, isoleucine, phenylalanine, arginine, cysteine and cystine; feed mixtures containing these additives and method of producing the dipeptides.
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- Application of phosphoramidate ProTide technology significantly improves antiviral potency of carbocyclic adenosine derivatives
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We report the application of phosphoramidate pronucleotide (ProTide) technology to the antiviral agent carbocyclic L-d4A (L-Cd4A). The phenyl methyl alaninyl parent ProTide of L-Cd4A was prepared by Grignard-mediated phosphorochloridate reaction and resulted in a compound with significantly improved anti-HIV (2600-fold) and HBV activity. We describe modifications of the aryl, ester, and amino acid regions of the ProTide and how these changes affect antiviral activity and metabolic stability. Separate and distinct SARs were noted for HIV and HBV. Additionally, ProTides were prepared from the D-nucleoside D-Cd4A and the dideoxy analogues L-CddA and D-CddA. These compounds showed more modest potency improvements over the parent drug. In conclusion, the ProTide approach is highly successful when applied to L-Cd4A with potency improvements in vitro as high as 9000-fold against HIV. With a view to preclinical candidate selection we carried out metabolic stability studies using cynomolgus monkey liver and intestinal S9 fractions.
- McGuigan, Christopher,Hassan-Abdallah, Alshaimaa,Srinivasan, Sheila,Wang, Yikang,Siddiqui, Adam,Daluge, Susan M.,Gudmundsson, Kristjan S.,Zhou, Huiqiang,McLean, Ed W.,Peckham, Jennifer P.,Burnette, Thimysta C.,Marr, Harry,Hazen, Richard,Condreay, Lynn D.,Johnson, Lance,Balzarini, Jan
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p. 7215 - 7226
(2007/10/03)
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- Hydroxamic acid-based bisubstrate analog inhibitors of Ras farnesyl protein transferase
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The rational design, synthesis, and activity of novel, hydroxamic acid- based, collective bisubstrate analog inhibitors of farnesyl protein transferase (FPT) is described. This class of compounds differ structurally from the conventional FPT inhibitors by
- Patel, Dinesh V.,Young, Marian G.,Robinson, Simon P.,Hunihan, Lisa,Dean, Brenda J.,Gordon, Eric M.
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p. 4197 - 4210
(2007/10/03)
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- Enzyme-Catalyzed Irreversible Formation of Peptides Containing D-Amino Acids
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Procedures have been developed for the preparation of dipeptides Z-L-Tyr-D-X and Z-L-Phe-D-X using Z-L-Tyr-OMe (or Z-L-Phe-OMe) and D-amino acid esters or amides (D-X) as substrates and soluble or immobilized α-chymotrypsin as a catalyst.The formation of each of these peptides in miscible or immiscible organic solvent-water systems in a kinetically controlled approach is virtually irreversible with no side reactions or racemization.Kinetic studies indicate that D-amino acid esters are about 100 times that of water and 10percent that of L-amino acid esters as a nucleophile in deacylation reactions.The effects of pH, organic solvents, temperature, and substrate and enzyme concentrations on the yield and the stability of the enzyme in syntheses have been studied and the results compared with those in the enzyme-catalyzed formation of L-L-dipeptides.
- West, J. Blair,Wong, Chi-Huey
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p. 2728 - 2735
(2007/10/02)
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