Modification and Optimization of the Bis-picolylamide-Based Relay Protection for Carboxylic Acids to be Cleaved by Unusual Complexation with Cu2+ Salts
摘要:
A simple modification of our recently published protection scheme for carboxylic acids as amides resulted in a new protecting group with significantly improved properties. It requires shorter reaction times for deprotection and allows us to replace Cu(OTf)(2) by CuCl2, indicating at the same time the importance of the nature of the anion of the Cu2+ source. Since the new scheme fulfills all criteria required for an ideal protection group it should find widespread application in synthetic organic chemistry.
Scalable Synthesis of Piperazines Enabled by Visible-Light Irradiation and Aluminum Organometallics
作者:Samuel Suárez-Pantiga、Kilian Colas、Magnus J. Johansson、Abraham Mendoza
DOI:10.1002/anie.201505608
日期:2015.11.16
The development of more active CH oxidation catalysts has inspired a rapid, scalable, and stereoselective assembly of multifunctional piperazines through a [3+3] coupling of azomethine ylides. A combination of visible‐light irradiation and aluminum organometallics is essential to promote this transformation, which introduces visible‐lightphotochemistry of main‐group organometallics and sets the basis
Modification and Optimization of the Bis-picolylamide-Based Relay Protection for Carboxylic Acids to be Cleaved by Unusual Complexation with Cu<sup>2+</sup> Salts
A simple modification of our recently published protection scheme for carboxylic acids as amides resulted in a new protecting group with significantly improved properties. It requires shorter reaction times for deprotection and allows us to replace Cu(OTf)(2) by CuCl2, indicating at the same time the importance of the nature of the anion of the Cu2+ source. Since the new scheme fulfills all criteria required for an ideal protection group it should find widespread application in synthetic organic chemistry.
Structural Characterization of Zinc(II)/Cobalt(II) Complexes of Chiral <i>N</i>-(Anthracen-9-yl)methyl-<i>N</i>,<i>N</i>-bis(2-picolyl)amine and Evaluation of DNA Photocleavage Activity
bis(2-picolyl)amine on the DNA photocleavage activity of metal complexes. The structures of ZnII and CoII complexes in APPE were analyzed via X-ray crystallography and fluorometric titration. APPE formed metal complexes with a 1 : 1 stoichiometry in both the crystalline and solution states. Fluorometric titration was used to show that the ZnII and CoII association constants of these complexes (log Kas)
我们设计并合成了手性配体N- (蒽-9-基甲基)-1-(吡啶-2-基) -N- (吡啶-2-基甲基)乙胺(APPE) DNA光裂解剂,以研究手性的影响双(2-吡啶甲基)胺对金属配合物DNA光裂解活性的影响。通过X 射线晶体学和荧光滴定分析了 APPE 中Zn II和 Co II配合物的结构。APPE 在结晶状态和溶液状态下形成化学计量比为 1:1 的金属配合物。使用荧光滴定法显示这些配合物的 Zn II和Co II缔合常数 (log Kas) 分别为 4.95 和 5.39。发现合成的复合物在 370 nm 照射时可切割 pUC19 质粒 DNA。Zn II配合物的 DNA 光裂解活性高于 Co II配合物。甲基连接碳的绝对构型并不影响 DNA 裂解活性,不幸的是,发现不含甲基的非手性 APPE 衍生物 (ABPM) 比 APPE 更有效地进行 DNA 光裂解。造成这种情况的原因之一可能是