硒醇在温和的无催化剂条件下与异氰酸酯反应,以良好的收率和高选择性生成硒代氨基甲酸酯,而不是潜在的竞争亲核加成。该方法能够结合多种官能团,从而提供对广泛的密集官能化硒代氨基甲酸酯的访问。在竞争性以杂原子为中心的亲核试剂存在下,异氰酸酯选择性地与硒醇偶联。硒氨基甲酸酯表现出类似硫醇过氧化物酶的特性,能够以硫醇为代价还原过氧化氢,硫醇被转化为相应的二硫化物。一系列控制实验表明催化机制通过一个途径进行,涉及 H 2 O 2- 促进氨基甲酰化反应,产生硫代氨基甲酸酯,同时释放具有催化活性的硒酸阴离子。通过过氧化物驱动的硫醇 - 硒醇交换,硒代氨基甲酸酯表现为具有硫醇过氧化物酶样活性的硒酸阴离子的等价物。
Organoselenium compounds from purines: Synthesis of 6-arylselanylpurines with antioxidant and anticholinesterase activities and memory improvement effect
作者:Luis Fernando B. Duarte、Renata L. Oliveira、Karline C. Rodrigues、Guilherme T. Voss、Benhur Godoi、Ricardo F. Schumacher、Gelson Perin、Ethel A. Wilhelm、Cristiane Luchese、Diego Alves
DOI:10.1016/j.bmc.2017.11.019
日期:2017.12
We describe here a simple method for the synthesis of 6-arylselanylpurines with antioxidant and anticholinesteraseactivities, and memory improvement effect. This class of compounds was synthesized in good yields by a reaction of 6-chloropurine with diaryl diselenides using NaBH4 as reducing agent and PEG-400 as solvent. Furthermore, the synthesized compounds were evaluated for their in vitro antioxidant
Glycerol as a promoting medium for cross-coupling reactions of diaryl diselenides with vinyl bromides
作者:Loren C. Gonçalves、Gabriela F. Fiss、Gelson Perin、Diego Alves、Raquel G. Jacob、Eder J. Lenardão
DOI:10.1016/j.tetlet.2010.10.107
日期:2010.12
herein the use of glycerol as a novel solvent in the cross-coupling reaction of diaryl diselenides with vinyl bromides catalyzed by CuI. This cross-coupling reaction was performed with diaryl diselenides and (Z)- or (E)-vinyl bromides bearing electron-withdrawing and electron-donating groups, affording the corresponding vinyl selenides in good to excellent yields. The mixture glycerol/catalyst can be
Metal-free visible-light induced cyclization/substitution cascade reaction of alkyne-tethered cyclohexadienones and diselenides: access to 5-hydroxy-3-selenyl-4a,8a-dihydro-2<i>H</i>-chromen-6(5<i>H</i>)-ones
A simple and efficient Se-radical triggered cyclization/substitution cascadereaction of alkyne-tethered cyclohexadienones to afford 5-hydroxy-3-selenyl-4a,8a-dihydro-2H-chromen-6(5H)-ones has been developed. This transformation via the 3,5-diselenyl-4a,8a-dihydro-2H-chromen-6(5H)-one intermediate followed by hydrolysis in the presence of CsOAc affords the desired product 3. The resulting products
Regioselective, Solvent- and Metal-Free Chalcogenation of Imidazo[1,2-<i>a</i>
]pyridines by Employing I<sub>2</sub>
/DMSO as the Catalytic Oxidation System
作者:Jamal Rafique、Sumbal Saba、Alisson R. Rosário、Antonio L. Braga
DOI:10.1002/chem.201600800
日期:2016.8.8
molecular‐iodine‐catalyzed chalcogenations (S and Se) of imidazo[1,2‐a]pyridines were achieved by using diorganoyl dichalcogenides undersolvent‐freeconditions. This approach afforded the desired products that had been chalcogenated regioselectively at the C3 position in up to 96 % yield by using DMSO as an oxidant, in the absence of a metal catalyst, and under an inert atmosphere. This mild, green approach allowed
通过在无溶剂条件下使用二有机基二卤化氢实现咪唑并[1,2- a ]吡啶的高效分子碘催化硫属元素化(S和Se)。通过使用DMSO作为氧化剂,在没有金属催化剂的情况下,并且在惰性气氛下,该方法提供了所需的产物,该产物已经在C3位置进行了区域硫磺化,产率高达96%。这种温和的绿色方法可以制备具有结构多样性的不同类型的硫族化咪唑并[1,2- a ]吡啶。此外,当前协议还扩展到其他N杂环核。
Organocatalytic Enantioselective Selenosulfonylation of a C–C Double Bond To Form Two Stereogenic Centers in an Aqueous Medium
Organocatalytic selenosulfonylation of the C–C doublebond of α,β-unsaturatedketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled