微环境敏感的荧光(ESF)核苷是用于核酸研究的强大工具。合成了新的5-取代的尿苷类似物,其包含通过5-硫代酰胺-尿苷与芳族α-溴羰基化合物的汉茨(Hantzsch)合成反应获得的4 H-环戊[ d ]噻唑环。新化合物的最大发射量在可见光区域。它们具有很强的溶剂和pH依赖性荧光特性,表明它们有望成为荧光探针。
A Suzuki Coupling Based Route to 2,2‘-Bis(2-indenyl)biphenyl Derivatives
作者:Edwin G. IJpeij、Felix H. Beijer、Henricus J. Arts、Claire Newton、Johannes G. de Vries、Gert-Jan M. Gruter
DOI:10.1021/jo016040i
日期:2002.1.1
Because of the promising performance in olefin polymerization of 2,2'-bis(2-indenyldiyl)biphenyl zirconium dichloride, we developed a new and broadly applicable route to 2,2'-bis(2-indenyl)biphenyl derivatives. Reaction of the known 2,2'-diiodobiphenyl (26) with the new 2-indenyl boronic acid (23) did not result in the desired 2,2'-bis(2-indenyl)biphenyl (10); instead an isomer thereof, (spiro-1,1-(2,2'-biphenyl)-2-(2-indenyl)indane) (27), was obtained. It was found that compound 10 could be made via a palladium-catalyzed reaction of 2,2-biphenyldiboronic acid (31) with 2-bromoindene (21) under standard Suzuki reaction conditions. However, the yield of this reaction was low at low palladium catalyst loadings, due to a competitive hydrolysis reaction of 2,2-biphenyldiboronic acid (31). HTE techniques were used to find an economically viable protocol. Thus, use of the commercially available 1.0 molar solution of (n-BU)(4)NOH in methanol with cosolvent toluene led to precipitation of the pure product in a fast and clean reaction, using only 0.7 mol % (0.35 mol % per C-C) of the expensive palladium catalyst.