Rhodium-Catalyzed Ketone Methylation Using Methanol Under Mild Conditions: Formation of α-Branched Products
作者:Louis K. M. Chan、Darren L. Poole、Di Shen、Mark P. Healy、Timothy J. Donohoe
DOI:10.1002/anie.201307950
日期:2014.1.13
The rhodium‐catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen‐borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α‐branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a
Novel functionalized melamine-based nitroheterocycles: synthesis and activity against trypanosomatid parasites
作者:Alessandro Baliani、Valerie Peal、Ludovic Gros、Reto Brun、Marcel Kaiser、Michael P. Barrett、Ian H. Gilbert
DOI:10.1039/b813394h
日期:——
Human African trypanosomiasis (HAT), caused by the protozoan parasite Trypanosoma brucei spp., is a major health problem in sub-Saharan Africa. New drugs are urgently required for the disease. Selective uptake of toxic compounds into trypanosomes has been achieved by exploiting plasma membrane transporters. For example, the P2 aminopurine transporter, along with other transporters, selectively concentrates melamine and benzamidine moieties into trypanosomes. We have previously reported the use of the melamine motif to selectively target nitrofuran to the trypanosome. In this paper we report the further investigation of the structure activity relationships and the effect of the introduction of different functionalized substituents onto the melamine unit. Most of the compounds tested in vitro for their trypanocidal activity showed activities in the submicromolar range against T. b. rhodesiense.
Cyclopentyl Methyl Ether: An Alternative Solvent for Palladium-Catalyzed Direct Arylation of Heteroaromatics
作者:Kassem Beydoun、Henri Doucet
DOI:10.1002/cssc.201000405
日期:2011.4.18
Some ethers, such as cyclopentyl methylether and di‐n‐butyl ether, which can be considered as “greener” solvents than N,N‐dimethylacetamide (DMAc) or DMF, can be advantageously employed for the palladium‐catalyzed direct arylation of heteroaromatics. In the presence of such ethers and only 0.5–1 mol % of palladium catalysts at 125–150 °C, the direct 5‐arylation of thiazoles, thiophenes, or furans
transition-metal-free direct α-C–H amination of ketones has been developed using commercially available ammonium iodide as the catalyst and sodium percarbonate as the co-oxidant. A wide range of ketone ((hetero)aromatic or nonaromatic ketones) and amine (primary/secondary amines, anilines, or amides) substrates undergo cross-coupling to generate synthetically useful α-amino ketones. The mechanistic studies indicated
Copper-Catalyzed Enantioselective Alkylation of Enolizable Ketimines with Organomagnesium Reagents
作者:Pablo Ortiz、Juan F. Collados、Ravindra P. Jumde、Edwin Otten、Syuzanna R. Harutyunyan
DOI:10.1002/anie.201609963
日期:2017.3.6
readily available organomagnesium reagents were used for the catalytic enantioselectivealkylation of enolizable N‐sulfonyl ketimines. The low reactivity and competing enolization of the ketimines was overcome by the use of a copper–phosphine chiral catalyst, which also rendered the transformation highly chemoselective and enantioselective for a broad range of ketimine substrates.