Chiral-at-metal iridium complex for efficient enantioselective transfer hydrogenation of ketones
作者:Cheng Tian、Lei Gong、Eric Meggers
DOI:10.1039/c6cc00972g
日期:——
A bis-cyclometalated iridium(III) complex with metal-centered chirality catalyzes the enantioselectivetransferhydrogenation of ketones with high enantioselectivities at low catalyst loadings down to 0.002 mol%. Importantly, the rate of catalysis...
prepared catalyst was characterized by FT-IR, 1H and 13C NMR techniques. The silica supported catalyst (‘SiO2’–NH2–RuII) was prepared by stirring [Ru(acac)2(CH3CN)2] with ‘SiO2’–NH2 in a 1 : 1 mixture of CH2Cl2–toluene for 3 days at room temperature. It was characterized by FT-IR, SEM, solid state NMR, ICP and BET surface area methods. The transferhydrogenation reaction of carbonylcompounds was carried
Functionalized 3(2H)-furanones via photooxygenation of (β-keto)-2-substituted furans: Application to the biomimetic synthesis of merrekentrone C
作者:Charis Gryparis、Ioannis N. Lykakis、Christina Efe、Ioannis-Panayotis Zaravinos、Theonymphi Vidali、Eugenia Kladou、Manolis Stratakis
DOI:10.1039/c1ob05567d
日期:——
Photooxygenation of (β-keto)-2-substituted furans leads, in a one pot operation, to functionalized 3(2H)-furanones with good to excellent yields. This methodology was applied as a key-step to the concise and biomimetic synthesis of the sesquiterpene merrekentrone C. The precursor to merrekentrone C, keto difuran, was synthesized using a cross coupling of α-iodo-3-acetylfuran with an alkenyl furan under Fenton-type conditions.
Inhibitors of Dihydrofolate Reductase With Antibacterial Antiprotozoal, Antifungal and Anticancer Properties
申请人:Anderson Amy C.
公开号:US20090105287A1
公开(公告)日:2009-04-23
The compositions and methods described herein discloses the design, synthesis and testing of compounds that act as inhibitors of DHFR. The basic scaffold of these inhibitors includes a 2,4-diaminopyrimidine ring with a propargyl linker to another substituted aryl, bicyclo or heteroaryl ring. These DHFR inhibitors are potent and selective for many different pathogenic organisms, including the DHFR enzyme from bacteria such as
Bacillus anthracis
and methicillin-resistant
Staphylococcus aureus
, fungi such as
Candida glabrata, Candida albicans
and
Cryptococcus neoformans
and protozoa such as
Cryptosporidium hominis
and
Toxoplasma gondii
. These compounds and other similar compounds are also potent against the mammalian enzyme and may be useful as anti-cancer therapeutics.
Triazolylidene Iridium Complexes for Highly Efficient and Versatile Transfer Hydrogenation of C═O, C═N, and C═C Bonds and for Acceptorless Alcohol Oxidation
oxidation. High-valent iridium(III) complexes were identified as the most active precursors for the oxidative alcohol dehydrogenation, while a low-valent iridium(I) complex with a methyl ether functionality was most active in reductive transfer hydrogenation. This catalyst precursor is highly versatile and efficiently hydrogenates ketones, aldehydes, imines, allylic alcohols, and most notably also unpolarized
据报道,一组铱(I)和铱(III)配合物带有三唑基亚烷基配体,这些配体包含苯并恶唑,噻唑和甲基醚侧基作为潜在的螯合供体位点。这些基团的键合模式通过NMR光谱和X射线结构分析来鉴定。在转移氢化和无受体醇氧化中,将该配合物评价为催化剂前体。高价铱(III)配合物被确定为氧化醇脱氢最活跃的前体,而具有甲基醚官能团的低价铱(I)配合物在还原转移氢化中最活跃。这种催化剂的前体用途广泛,可以有效地氢化酮,醛,亚胺,烯丙基醇,尤其是非极化烯烃,转移加氢反应非常困难的基质。周转频率高达260小时记录了–1的烯烃氢化反应,而氢转移到酮和醛中的最大周转频率大于2000 h –1。结合同位素标记实验,动力学同位素效应测量和Hammett参数相关性进行的机械研究表明,限制转移的步骤是转移氢化过程中金属从氢化物向基质的氢化物转移,而在醇脱氢中,限制步骤是基质协调到金属中心。