- Lewis acid facilitated regioselective synthesis of τ-histidinoalanine
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τ-Histidinoalanine, with an unusual cross-link between His and Ala, is the central component of theonellamides, a family of bioactive peptidic natural products. Previous syntheses of this residue were plagued with low regioselectivity in the alkylation step. Herein, we report two novel routes to τ-histidinoalanine, involving alkylation of Boc-His-OMe with a serine-derived β-lactone and β-bromoalanine, respectively, as the electrophiles. The use of Mg(OTf)2 as a catalyst was found to be essential to ensure high regioselectivity for the τ-isomer, presumably due to the formation of a six-membered ring chelation involving the π-nitrogen atom of histidine.
- Wu, Ju,Ma, Bing,Wang, Yuehui,Zhang, Yue,Yan, Shenghu,Castle, Steven L.
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p. 3114 - 3116
(2014/05/20)
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- N -(2-Oxo-3-oxetanyl)carbamic acid esters as N-acylethanolamine acid amidase inhibitors: Synthesis and structure-activity and structure-property relationships
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The β-lactone ring of N-(2-oxo-3-oxetanyl)amides, a class of N-acylethanolamine acid amidase (NAAA) inhibitors endowed with anti-inflammatory properties, is responsible for both NAAA inhibition and low compound stability. Here, we investigate the structure-activity and structure-property relationships for a set of known and new β-lactone derivatives, focusing on the new class of N-(2-oxo-3-oxetanyl)carbamates. Replacement of the amide group with a carbamate one led to different stereoselectivity for NAAA inhibition and higher intrinsic stability, because of the reduced level of intramolecular attack at the lactone ring. The introduction of a syn methyl at the β-position of the lactone further improved chemical stability. A tert-butyl substituent in the side chain reduced the reactivity with bovine serum albumin. (2S,3R)-2-Methyl-4-oxo-3-oxetanylcarbamic acid 5-phenylpentyl ester (27, URB913/ARN077) inhibited NAAA with good in vitro potency (IC50 = 127 nM) and showed improved stability. It is rapidly cleaved in plasma, which supports its use for topical applications.
- Duranti, Andrea,Tontini, Andrea,Antonietti, Francesca,Vacondio, Federica,Fioni, Alessandro,Silva, Claudia,Lodola, Alessio,Rivara, Silvia,Solorzano, Carlos,Piomelli, Daniele,Tarzia, Giorgio,Mor, Marco
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p. 4824 - 4836
(2012/07/03)
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- Synthesis of histidinoalanine: A comparison of β-lactone and sulfamidate electrophiles
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Previous syntheses of histidinoalanine (HAL) have led to mixtures of regioisomers and/or stereoisomers. For example, opening of N-Cbz-d-serine- β-lactone (6) with Boc-l-His-OMe (5) gave a 2:1 mixture of τ- and π-regioisomers. The sulfamidate 10, derived f
- Taylor, Carol M.,De Silva, Samanthi Thabrew
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experimental part
p. 5703 - 5708
(2011/09/16)
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- Synthesis of phalluside-1 and Sch II using 1,2-metallate rearrangements
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(4E,8E,10E)-9-Methyl-4,8,10-sphingatrienine, a core component of marine sphingolipids, was synthesised for the first time using a copper(i)-mediated 1,2-metallate rearrangement of a lithiated glycal as a key step. It was converted to phalluside-1, a cereb
- Black, Fiona J.,Kocienski, Philip J.
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supporting information; scheme or table
p. 1188 - 1193
(2010/06/15)
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- INDOLE OR BENZIMIDAZOLE DERIVATIVES FOR MODULATING IκB KINASE
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The invention relates to compounds of formula (I). Said compounds are suitable for producing medicaments for the prophylaxis and treatment of diseases, the progression of which involves increased activity of IκB kinase.
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Page/Page column 12-13
(2010/11/30)
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- Serine and threonine β-lactones: A new class of hepatitis A virus 3C cysteine proteinase inhibitors
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Hepatitis A virus (HAV) 3C enzyme is a cysteine proteinase essential for viral replication and infectivity and represents a target for the development of antiviral drugs. A number of serine and threonine β-lactones were synthesized and tested against HAV 3C proteinase. The D-N-Cbz-serine β-lactone 5a displays competitive reversible inhibition with a Ki value of 1.50 × 10-6 M. Its enantiomer, L-N-Cbz-serine β-lactone 5b is an irreversible inactivator with kinact = 0.70 min-1, KI = 1.84 × 10-4 M and kinact/KI = 3800 M-1 min-1. Mass spectrometry and HMQC NMR studies using 13C-labeled 5b show that inactivation of the enzyme occurs by nucleophilic attack of the cysteine thiol (Cys-172) at the β-position of the oxetanone ring. Although the N-Cbz-serine β-lactones 5a and 5b display potent inhibition, other related analogues with an N-Cbz side chain, such as the five-membered ring homoserine γ-lactones 14a and 14b, the four-membered ring β-lactam 33, 2-methylene oxetane 34, cyclobutanone 36, and 3-azetidinone 39, fail to give significant inhibition of HAV 3C proteinase, thus demonstrating the importance of the β-lactone ring for binding.
- Lall, Manjinder S.,Ramtohul, Yeeman K.,James, Michael N.G.,Vederas, John C.
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p. 1536 - 1547
(2007/10/03)
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