- Enzymatic enantioselective decarboxylative protonation of heteroaryl malonates
-
The enzyme aryl/alkenyl malonate decarboxylase (AMDase) catalyses the enantioselective decarboxylative protonation (EDP) of a range of disubstituted malonic acids to give homochiral carboxylic acids that are valuable synthetic intermediates. AMDase exhibits a number of advantages over the non-enzymatic EDP methods developed to date including higher enantioselectivity and more environmentally benign reaction conditions. In this report, AMDase and engineered variants have been used to produce a range of enantioenriched heteroaromatic α-hydroxycarboxylic acids, including pharmaceutical precursors, from readily accessible α-hydroxymalonates. The enzymatic method described here represents an improvement upon existing synthetic chemistry methods that have been used to produce similar compounds. The relationship between the structural features of these new substrates and the kinetics associated with their enzymatic decarboxylation is explored, which offers further insight into the mechanism of AMDase. Versatile decarboxylase: Aryl malonate decarboxylase (AMDase) and engineered variants have been shown to catalyse the enatioselective decarboxylative protonation of a range of α-heteroaryl α-hydroxy malonates with excellent yields and enantioselectivity (see scheme).
- Lewin, Ross,Goodall, Mark,Thompson, Mark L.,Leigh, James,Breuer, Michael,Baldenius, Kai,Micklefield, Jason
-
-
Read Online
- Synthesis of α-hydroxycarboxylic acids from various aldehydes and ketones by direct electrocarboxylation: A facile, efficient and atom economy protocol
-
In present work, the formation of α-hydroxycarboxylic acids have been described from various aromatic aldehydes and ketones via direct electrocarboxylation method with 80-92% of yield without any side product and can be purified by simple recrystallization using sacrificial Mg anode and Pt cathode in an undivided cell, CO2at (1 atm) was continuously bubbled in the cell throughout the reaction using tetrapropylammonium chloride as a supporting electrolyte in acetonitrile. The synthesized compounds obtained in fair to excellent yield with a high level of purity. The characterization of electrocarboxylated compounds was done with spectroscopic techniques like IR, NMR (1H & 13C), mass and elemental analysis.
- Singh, Kishanpal,Sohal, Harvinder Singh,Singh, Baljit
-
p. 839 - 845
(2021/04/09)
-
- Carboxylation with CO2 via brook rearrangement: Preparation of α-hydroxy acid derivatives
-
In the presence of CsF, a wide range of α-substituted α-siloxy silanes were carboxylated under a CO2 atmosphere (1 atm) via Brook rearrangement. A variety of α-substituents including aryl, alkenyl, and alkyl groups were tolerated to afford α-hydroxy acids in moderate-to-high yields. One-pot synthesis from aldehydes using PhMe2SiLi and CO 2 was also possible, providing α-hydroxy acids without the isolation of an α-hydroxy silane.
- Mita, Tsuyoshi,Higuchi, Yuki,Sato, Yoshihiro
-
-
- Amberlyst A-26: An efficient and reusable heterogeneous catalyst for a one-pot oxidation-Cannizarro reaction
-
Amberlyst A-26 catalyses the efficient synthesis of α-hydroxy- arylacetic acids from aryl methyl ketones in the presence of SeO2. After simple separation, the catalyst does not lose its activity and can be reused without significant loss in activity for at least four cycles.
- Shen, Ming-Gui,Shang, Shi-Bin,Song, Zhan-Qian,Wang, Dan,Rao, Xiao-Ping,Gao, Hong,Liu, He
-
-
- Muscarinic receptor antagonists
-
The present invention relates generally to muscarinic receptor antagonist, which are useful, among other uses, for the treatment of various diseases of the respiratory, urinary and gastrointestinal systems mediated through muscarinic receptors. The invention also relates to the process for the preparation of disclosed compounds, pharmaceutical compositions containing the disclosed compounds and the method for treating diseases mediated through muscarinic receptors. Also provided herein are pharmaceutical composition comprising one or more muscarinic receptor antagonists and at least one other active ingredients include, but are not limited to, corticosteroids, beta agonists, leukotriene antagonists, 5-lipoxygenase inhibitors, anti-histamines, antitussives, dopamine receptor antagonists, chemokine inhibitors, p38 MAP Kinase inhibitors, and PDE-IV inhibitors.
- -
-
Page/Page column 10
(2009/12/24)
-
- MUSCARINIC RECEPTOR ANTAGONISTS
-
The present invention relates generally to muscarinic receptor antagonist, which are useful, among other uses, for the treatment of various diseases of the respiratory, urinary and gastrointestinal systems mediated through muscarinic receptors. The invention also relates to the process for the preparation of disclosed compounds, pharmaceutical compositions containing the disclosed compounds and the method for treating diseases mediated through muscarinic receptors. Also provided herein are pharmaceutical composition comprising one or more muscarinic receptor antagonists and at least one other active ingredients include, but are not limited to, corticosteroids, beta agonists, leukotriene antagonists, 5-lipoxygenase inhibitors, anti-histamines, antitussives, dopamine receptor antagonists, chemokine inhibitors, p38 MAP Kinase inhibitors, and PDE-IV inhibitors.
- -
-
Page/Page column 7
(2010/01/31)
-
- ONE-STEP SYNTHESIS OF α-HYDROXY ACIDS VIA REDUCTIVE DOUBLE CARBONYLATION OF ORGANIC HALIDES
-
Palladium-catalyzed carbonylation of organic halides with water in the presence of calcium hydroxide or lithium hydroxide in primary or secondary alcoholic solvents afforded α-hydroxy acids.
- Kobayashi, Toshi-aki,Sakakura, Toshiyasu,Tanaka, Masato
-
p. 2721 - 2722
(2007/10/02)
-
- Process for preparing thiophene derivatives
-
Process for the preparation of a series of thiophene derivatives, from which 2-thiopheneacetic acid derivatives can easily be prepared, in high yields and selectivity by using substituted or unsubstituted 2-acetylthiophenes as the starting materials by easy operations. 2-Thiopheneacetic acid derivatives are very useful compounds as the chemical modifier of penicillin and cephalosporin. In the course of the reaction, 2-(dihaloacetyl)thiophenes are formed which are valuable intermediates for the production of not only 2-thiopheneacetic acids but also thioprofenic acid which is known as an anti-inflammatory agent.
- -
-
-
- Process for preparing thiophene derivatives and thiophene derivatives obtained thereby
-
Process for the preparation of a series of thiophene derivatives, from which 2-thiopheneacetic acid derivatives can easily be prepared, in high yields and selectivity by using substituted or unsubstituted thiophenes as the starting materials by easy operations. 2-Thiopheneacetic acid derivatives are very useful compounds as the chemical modifier of penicillin and cephalosporin. Novel compounds, i.e. α-arylthio-2-thiopheneacetic acids are also disclosed. These compounds are useful as the intermediates of the synthesis of 2-thiopheneacetic acids.
- -
-
-