850662-61-2Relevant academic research and scientific papers
Nickel-Catalyzed Reduction of Secondary and Tertiary Amides
Simmons, Bryan J.,Hoffmann, Marie,Hwang, Jaeyeon,Jackl, Moritz K.,Garg, Neil K.
supporting information, p. 1910 - 1913 (2017/04/11)
The nickel-catalyzed reduction of secondary and tertiary amides to give amine products is reported. The transformation is tolerant of extensive variation with respect to the amide substrate, proceeds in the presence of esters and epimerizable stereocenters, and can be used to achieve the reduction of lactams. Moreover, this methodology provides a simple tactic for accessing medicinally relevant α-deuterated amines.
Discovery of allosteric and selective inhibitors of inorganic pyrophosphatase from mycobacterium tuberculosis
Pang, Allan H.,Garzan, Atefeh,Larsen, Martha J.,McQuade, Thomas J.,Garneau-Tsodikova, Sylvie,Tsodikov, Oleg V.
, p. 3084 - 3092 (2016/11/29)
Inorganic pyrophosphatase (PPiase) is an essential enzyme that hydrolyzes inorganic pyrophosphate (PPi), driving numerous metabolic processes. We report a discovery of an allosteric inhibitor (2,4-bis(aziridin-1-yl)-6-(1-phenylpyrrol-2-yl)-s-triazine) of bacterial PPiases. Analogues of this lead compound were synthesized to target specifically Mycobacterium tuberculosis (Mtb) PPiase (MtPPiase). The best analogue (compound 16) with a Ki of 11 μM for MtPPiase is a species-specific inhibitor. Crystal structures of MtPPiase in complex with the lead compound and one of its analogues (compound 6) demonstrate that the inhibitors bind in a nonconserved interface between monomers of the hexameric MtPPiase in a yet unprecedented pairwise manner, while the remote conserved active site of the enzyme is occupied by a bound PPi substrate. Consistent with the structural studies, the kinetic analysis of the most potent inhibitor has indicated that it functions uncompetitively, by binding to the enzyme-substrate complex. The inhibitors appear to allosterically lock the active site in a closed state causing its dysfunctionalization and blocking the hydrolysis. These inhibitors are the first examples of allosteric, species-selective inhibitors of PPiases, serving as a proof-of-principle that PPiases can be selectively targeted.
Organic synthesis via magnetic attraction: Benign and sustainable protocols using magnetic nanoferrites
Nasir Baig,Varma, Rajender S.
, p. 398 - 417 (2013/03/14)
Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal-Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide-alkynes-cycloaddition (AAC) reactions, C-S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
Magnetic Nanoparticle-Supported Glutathione as a Sustainable Organocatalyst
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Page/Page column 6-8, (2011/04/14)
This invention relates to the use of nano-organocatalysts, and, more specifically, to the use of magnetic nanomaterial-supported organocatalysts. It is an object of the present invention to provide “green” catalysts and protocols. According to one embodiment of the invention, a nano-organocatalyst in the form of a magnetic nanomaterial-supported organocatalyst is provided. According to other embodiments of the invention, glutathione and cysteine are provided as organocatalysts and magnetic nanomaterial-supported glutathione and magnetic nanomaterial-supported cysteine are provided for use as nano-organocatalysts. According to another embodiment of the invention, a method of using a recyclable magnetic nanomaterial-supported organocatalyst using a totally benign aqueous protocol, without using any organic solvent in the reaction or during the workup, is provided. According to a further embodiment of the invention, a recyclable magnetic nanomaterial-supported organocatalyst for various organocatalytic reactions, including but not limited to Paal-Knorr reactions, aza-Michael addition and pyrazole synthesis, is provided.
Decarboxylative formation of N-alkyl pyrroles from 4-hydroxyproline
Deb, Indubhusan,Coiro, Daniel J.,Seidel, Daniel
scheme or table, p. 6473 - 6475 (2011/06/28)
N-Alkyl pyrroles are obtained in a single step from 4-hydroxyproline and aldehydes in just 15 min under microwave irradiation.
Nano-organocatalyst: magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis
Polshettiwar, Vivek,Varma, Rajender S.
experimental part, p. 1091 - 1097 (2010/03/25)
Postsynthetic surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity, and high selectivity of nano-organocatalysts for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis. Their insoluble character coupled with paramagnetic nature enables easy separation of these nano-catalysts from the reaction mixture using external magnet, which eliminates the requirement of catalyst filtration.
Magnetic nanoparticle-supported glutathione: A conceptually sustainable organocatalyst
Polshettiwar, Vivek,Baruwati, Babita,Varma, Rajender S.
supporting information; experimental part, p. 1837 - 1839 (2009/10/23)
A conceptually novel nanoparticle-supported and magnetically recoverable organocatalyst has been developed, which is readily prepared from inexpensive starting materials in a truly sustainable manner; which catalyzes the Paal-Knorr reaction with high yield in pure aqueous medium that avoids the use of toxic organic solvents, even in the workup step.
Potassium carbonate as a base for the N-alkylation of indole and pyrrole in ionic liquids
Jorapur, Yogesh R.,Jeong, Jae Min,Chi, Dae Yoon
, p. 2435 - 2438 (2007/10/03)
The methodology for the N-alkylation of indole and pyrrole using potassium carbonate in 1-n-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] as the sustainable reaction media with acetonitrile as the cosolvent is described herein. Our approach provides good yields with alkyl halides as well as sulfonates as the electrophiles. Cesium carbonate was also found to be a consistent base in the N-alkylation. The proposed methodology is simple and mild with easy workup.
Mono- and dialkylations of pyrrole at C2 and C5 positions by nucleophilic substitution reaction in ionic liquid
Jorapur, Yogesh R.,Lee, Chang-Hee,Chi, Dae Yoon
, p. 1231 - 1234 (2007/10/03)
(Chemical Equation Presented) A novel ionic liquid methodology for pyrrole C-alkylation is described. The pyrrole alkylation is achieved with various simple alkyl halides and mesylates selectively at C2 and C5 positions in good yields with minimal byproducts under relatively mild conditions in various ionic liquids. 2-(3-Phenylpropyl)pyrrole (2a) was synthesized from pyrrole and 1-bromo-3-phenylpropane in a mixture solvent system, [bmim][SbF6] and CH3CN, in 81% yield at 115°C for 44 h with 5% yield of dialkylated compound 3a.
