- Visible-Light-Mediated, Chemo- and Stereoselective Radical Process for the Synthesis of C-Glycoamino Acids
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An approach for efficient synthesis of C-glycosyl amino acids is described. Different from typical photoredox-catalyzed reactions of imines, the new process follows a pathway in which α-imino esters serve as electrophiles in chemoselective addition reactions with nucleophilic glycosyl radicals. The process is highlighted by the mild nature of the reaction conditions, the highly stereoselectivity attending C-C bond formation, and its applicability to C-glycosylations using both armed and disarmed pentose and hexose derivatives.
- Ji, Peng,Zhang, Yueteng,Wei, Yongyi,Huang, He,Hu, Wenbo,Mariano, Patrick A.,Wang, Wei
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supporting information
p. 3086 - 3092
(2019/05/01)
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- MACROCYCLIC MCL-1 INHIBITORS AND METHODS OF USE
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The present disclosure provides for compounds of Formula (I) wherein A2, A3, A4, A6, A7, A8, A15, RA, R5, R9, R10A, R10B, R11, R12, R13, R14, R16, W, X, and Y have any of the values defined in the specification, and pharmaceutically acceptable salts thereof, that are useful as agents in the treatment of diseases and conditions, including cancer. Also provided are pharmaceutical compositions comprising compounds of Formula (I).
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Paragraph 00243
(2019/03/05)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- Acyl transfer reactions of carbohydrates, alcohols, phenols, thiols and thiophenols under green reaction conditions
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Acyl transfer reactions of various carbohydrates, alcohols, phenols, thiols and thiophenols were achieved at room temperature in high yields and catalytic efficiency in the presence of methane sulfonic acid, a green organic acid, under solvent-free conditions over short time periods. The method is mild enough to allow acid labile substituents such as isopropylidene acetals and trityl ethers on the reacting substrates to be left completely unaffected. Esterification of free mono- and dicarboxylic acids such as acetic acid, cinnamic acid, sialic acid and tartaric acid with alcohols such as menthol, ethanol, methanol or propylene glycol has also been achieved efficiently at room temperature. A comparative study of the method with the silica-sulfuric acid is also reported.
- Giri, Santosh Kumar,Kartha, K. P. Ravindranathan
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p. 11687 - 11696
(2015/02/19)
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- Design, synthesis and antifibrotic activities of carbohydrate-modified 1-(substituted aryl)-5-trifluoromethyl-2(1H) pyridones
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Pirfenidone, a pyridone compound, is an effective and novel antifibrotic agent. In this article, we describe the design, synthesis and activity evaluation of novel antifibrotic agents, 1-(substituted aryl)-5-trifluoromethyl- 2(1H) pyridones modified with
- Lou, Qinghua,Meng, Xiangbao,Lao, Zhiqi,Xuan, Lingling,Bai, Jinye,Hou, Qi,Hu, Gaoyun,Luo, Renna,Tao, Lijian,Li, Zhongjun
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scheme or table
p. 884 - 896
(2012/03/09)
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- Synthesis of a Candida albicans tetrasaccharide spanning the β1,2-mannan phosphodiester α-mannan junction
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The cell wall phosphomannan of Candida species is a complex N-linked glycoprotein with a glycan chain containing predominantly an α-linked mannose backbone with α-mannose branches. A minor β-mannan component is attached to the branches either via a glycos
- Dang, Anh-Thu,Johnson, Margaret A.,Bundle, David R.
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p. 8348 - 8360
(2012/11/07)
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- Design, synthesis, and biological evaluation of novel carbohydrate-based sulfamates as carbonic anhydrase inhibitors
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Carbonic anhydrases (CAs) IX and XII are enzymes with newly validated potential for the development of personalized, first-in-class cancer chemotherapies. Here we present the design and synthesis of novel carbohydrate-based CA inhibitors, several of which were very efficient inhibitors (Ki10 nM) with good selectivity for cancer-associated CA isozymes over off-target CA isozymes. All inhibitors comprised a carbohydrate core with one hydroxyl group derivatized as a sulfamate. Five different carbohydrates were chosen to present a selection of molecular shapes with subtle stereochemical differences to the CA enzymes active site. Variable modifications of the remaining sugar hydroxyl groups were incorporated to provide an incremental coverage of chemical property parameters that are associated with biopharmaceutical performance. All sulfamate inhibitors displayed ligand efficiencies that are consistent with those reported for good drug lead candidates.
- Lopez, Marie,Trajkovic, Jonathan,Bornaghi, Laurent F.,Innocenti, Alessio,Vullo, Daniela,Supuran, Claudiu T.,Poulsen, Sally-Ann
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supporting information; experimental part
p. 1481 - 1489
(2011/05/12)
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- DABCO: An efficient promoter for the acetylation of carbohydrates and other substances under solvent-free conditions
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A simple, mild and efficient solvent-free method for the acetylation of carbohydrates, and their partially protected derivatives, as well as non-carbohydrate substances in excellent yields in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is described with the advantage of tolerance to various functional groups, short reaction time and ease of product isolation.
- Ch, Ratnasekhar,Tyagi, Mohit,Patil, Premanand Ramrao,Kartha, K.P. Ravindranathan
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experimental part
p. 5841 - 5846
(2011/12/03)
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- Novel selectivity in carbohydrate reactions, IV: DABCO-mediated regioselective primary hydroxyl protection of carbohydrates
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An efficient procedure for the regioselective tritylation of primary hydroxyl group of aldohexopyranosides and nucleosides using trityl chloride in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) in dichloromethane has been developed. Subsequent acetylation of the tritylated products in the same pot has been made possible, thereby providing an efficient route to the fully protected carbohydrate derivatives that can be discriminated chemoselectively.
- Gadakh, Bharat Kacheshwar,Patil, Premanand Ramrao,Malik, Satish,Kartha, K. P. Ravindranathan
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experimental part
p. 2430 - 2438
(2009/12/03)
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- Fe2(SO4)3·xH2O-catalyzed per-O-acetylation of sugars compatible with acid-labile protecting groups adopted in carbohydrate chemistry
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Fully acetylated saccharides are inexpensive and very useful starting materials for the synthesis of many naturally occurring glycosides, oligosaccharides, and glycoconjugates. Ferric sulfate hydrate (Fe2(SO4)3·xH2O) was found to be a valuable Lewis acid promoter in the per-O-acetylation reaction of saccharides with acetic anhydride in 100% of conversion rate and 88-99% yields. Interestingly, the procedure is perfectly compatible with the presence of a variety of acid-labile protecting groups, such as isopropylidene, benzylidene, trityl, and TBDMS groups. The reactions were simply performed by stirring the mixture of a sugar with a slight excessive acetic anhydride in the presence of 2.0 mol % of Fe2(SO4)3·xH2O at rt and the pure products were obtained by a simple dilution of the reaction mixture with dichloromethane and washings with aqueous Na2CO3.
- Shi, Lei,Zhang, Guisheng,Pan, Feng
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p. 2572 - 2575
(2008/09/19)
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- Application of ball milling technology to carbohydrate reactions: I. Regioselective primary hydroxyl protection of hexosides and nucleoside by planetary ball milling
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Dry ball milling of hexosides with trityl chloride in the presence of DABCO or Na2CO3 has been found to result in their complete conversion to the respective 6-O-trityl ethers. Further wet grinding of the reaction mixture with Ac2O in the presence of DMAP led to the respective fully protected hexosides in good to excellent yields after isolation. It has been found to be an effective one-pot two-step synthesis under solvent-free condition. The speed of homogenization has been shown to highly influence the rate and outcome of the reaction, and commercially available planetary ball mill has been proved to be very convenient for carrying out the reaction under standardized and reproducible conditions.
- Patil, Premanand Ramrao,Kartha, K.P. Ravindranathan
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p. 279 - 293
(2008/12/21)
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- A facile, one-step conversion of 6-O-trityl and 6-O-TBDMS monosaccharides into the corresponding formate esters
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A convenient method has been developed for a facile and high-yield conversion of 6-O-tert-butyldimethylsilyl and 6-O-trityl protected monosaccharides to their formate esters, which may serve as useful intermediates for the replacement of the primary hydro
- Komiotis, Dimitri,Agelis, George,Manta, Stella,Tzioumaki, Niki,Tsoukala, Evangelia,Antonakis, Kostas
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p. 441 - 450
(2007/10/03)
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- SYNTHESIS OF 1,2-O-CYANOETHYLIDENE DERIVATIVES OF ALKYL GLYCOPYRANURONATES BY OXIDATION OF THE 6-TRITYL ETHERS OF THEIR HEXOSE ANALOGUES
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The synthesis of 1,2-O-cyanoethylidene derivatives (CED) of alkyl glycopyranuronates with the D-Glc, D-Gal, and D-Man configurations is described by oxidation of the 3,4-di-O-acetyl-6-O-trityl-CED-hexose analogues with the Jones reagent .The isopropylidenation of hydroxyl-containing triphenylmethyl ethers is demonstrated.
- Betaneli, Vitali I.,Ott, Andrej Ya.,Brukhanova, Olga V.,Kochetkov, Nikolay K.
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- Synthesis and characterization of methyl 6-O-alpha- and -beta-D-galactopyranosyl-beta-D-galactopyranoside.
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Sequential tritylation, acetylation and detritylation of methyl beta-D-galactopyranoside gave crystalline methyl 2,3,4-tri-O-acetyl-beta-D-galactopyranoside (4) and methyl 2,3,6-tri-O-acetyl-beta-D-galactopyranoside, the latter being the minor product resulting from acetyl migration. Reaction of 4 with 2,3,4,6-tetra-O-acetyl-alpha-D-galactosyl bromide in benzene, in the presence of mercuric cyanide and mercuric bromide, gave the alpha- and beta-D-(1----6)-linked disaccharides (7 and 9, respectively) in high yield, and their structure was confirmed by 1H- and 13C-n.m.r. 1d. and 2d. spectroscopy. O-Deacetylation of 7 gave the hitherto unknown, crystalline methyl 6-O-alpha-D-galactopyranosyl-beta-D-galactopyranoside. O-Deacetylation of 9 gave the corresponding, beta-D-linked disaccharide methyl glycoside, the physical constants of which are discussed with respect to controversial data in the literature.
- Kovac,Sokoloski,Glaudemans
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p. 101 - 109
(2007/10/02)
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