A New Synthesis of Naphthyridinones and Quinolinones: Palladium-Catalyzed Amidation of o-Carbonyl-Substituted Aryl Halides
摘要:
An alternative to the Friedlander condensation for the synthesis of naphthyridinones and quinolinones has been discovered. Palladium-catalyzed amidation of halo aromatics substituted in the ortho position by a carbonyl functional group or its equivalent with primary or secondary amides leads to the formation of substituted naphthyridinones and quinolinones.
Enantioselective Intermolecular Excited-State Photoreactions Using a Chiral Ir Triplet Sensitizer: Separating Association from Energy Transfer in Asymmetric Photocatalysis
作者:Jian Zheng、Wesley B. Swords、Hoimin Jung、Kazimer L. Skubi、Jesse B. Kidd、Gerald J. Meyer、Mu-Hyun Baik、Tehshik P. Yoon
DOI:10.1021/jacs.9b06244
日期:2019.8.28
substantial challenge in synthetic chemistry, and intermolecular pho-toreactions have proven especially difficult to conduct in a stereocontrolled fashion. Herein, we report a highly enantioselective intermo-lecular [2+2] cycloaddition of 3-alkoxyquinolones catalyzed by a chiral hydrogen-bonding iridium photosensitizer. Enantioselectivities as high as 99% ee were measured in reactions with a range of maleimides
激发态光反应的对映选择性催化仍然是合成化学中的一个重大挑战,并且已证明分子间光反应特别难以以立体控制的方式进行。在此,我们报告了由手性氢键合铱光敏剂催化的 3-烷氧基喹诺酮类的高度对映选择性分子间 [2+2] 环加成反应。在与一系列马来酰亚胺和其他缺电子烯烃反应伙伴的反应中测量到高达 99% ee 的对映选择性。一系列动力学、光谱和计算研究支持光催化剂和喹诺酮形成氢键复合物以控制选择性的机制,但在该复合物光激发后,优选马来酰亚胺的能量转移敏化。然后敏化的马来酰亚胺与氢键合的喹诺酮-光催化剂复合物反应,得到高度对映体富集的环加合物。这一发现与对映选择性光化学的长期信条相矛盾,该信条认为立体选择性光反应需要与敏化底物的强预缔合,以克服电子激发有机分子的短寿命。因此,该系统表明不对称光催化的更广泛的替代设计策略可能是可能的。这一发现与对映选择性光化学的长期信条相矛盾,该信条认为立体选择性光反应需
Engineering Boron Hot Spots for the Site‐Selective Installation of Iminoboronates on Peptide Chains
作者:Roberto Russo、Rita Padanha、Fábio Fernandes、Luis F. Veiros、Francisco Corzana、Pedro M. P. Gois
DOI:10.1002/chem.202002675
日期:2020.11.26
BAs on peptidechains. In this study, a “boronhotspot“ based on the 3‐hydroxyquinolin‐2(1H)‐one scaffold was developed and upon installation on a peptide N‐terminal cysteine, enables the site‐selective formation of iminoboronates with 2‐formyl‐phenyl boronic acids (Ka of 58128±2 m−1). The reaction is selective in the presence of competing lysine ϵ‐amino groups, and the resulting iminoboronates, displayed
硼酸(BAs)是设计动态材料的一种有前途的生物共轭功能,因为它们可以与对不同pH,ROS,碳水化合物和谷胱甘肽水平响应的氧/氮亲核试剂建立可逆的共价键。然而,这些键的动力学性质也限制了对生物缀合的稳定性和位点选择性的控制,这最终导致在生理条件下稳定性差的异质缀合物。在这里,我们公开了一种在肽链上安装BA的新策略。在这项研究中,开发了基于3-羟基喹啉-2(1 H)-one支架的“硼热点”,并将其安装在肽的N端半胱氨酸上,能够与2-甲酰基选择性地形成亚氨基硼酸酯。苯硼酸(K a58128±2 m -1)。在竞争性赖氨酸ϵ-氨基存在下,该反应具有选择性,所得的亚氨基硼酸酯在缓冲溶液中显示出改善的稳定性,在谷胱甘肽存在下具有可裂解的特性。一旦开发完成,该方法就可用于制备具有层粘连蛋白片段的可裂解的荧光偶联物,从而可以验证67LR受体是否是将货物运送至癌症HT29细胞的靶标。
Reactions of 3-Substituted Quinoline 1-Oxides with Acylating Agents
Reactions of 3-fluoro- (1a), 3-bromo,- (1b), 3-methyl- (1c), 3-methoxy- (1d) and 3-acetamidoquinoline 1-oxides (1e) with acylating agents (POCl3, Ac2O, TsCl and PhCOCl) were examined (Table). While only 2-substituted quinolines were obtained from 1a and 1b, fair amounts of 4-substituted products were formed in reactions of 1d, the sole formation of the 4-acetoxyquinoline (6) with Ac2O being the most significant result. 2-Chloroquinolines, 4-chloroquinolines and 2-tosyloxy-quinolines were formed (and sometimes predominate) in addition to 2-quinolinones in reactions with TsCl.
Albini, Angelo; Fasani, Elisa; Dacrema, Lucia Maggi, Journal of the Chemical Society. Perkin transactions I, 1980, p. 2738 - 2742