Intramolecular Pd(II)-Catalyzed Cyclization of Propargylamides: Straightforward Synthesis of 5-Oxazolecarbaldehydes
摘要:
Direct synthesis of 2-substituted 5-oxazolecarbaldehydes was performed by intramolecular reaction of propargylamides through treatment with a catalytic amount of Pd(II) salts in the presence of a stoichiometric amount of reoxidant agent. The heterocyclization process was well-tolerated by a wide range of aryl, heteroaryl, and alkyl propargylamides. This protocol constitutes a valuable synthetic pathway to 5-oxazolecarbaldehydes, alternative to the formylation on oxazole rings, often unsatisfactory in term of regioselectivity and yields.
The synthesis of potentially bioactive pyrroloazepinones based on the catalytic intramolecularcyclization of alkyne-substituted 1H-pyrrole-2-carboxylic acid amides has been developed. In the presence of either H2PtCl6·6H2O at 120 °C or AuCl3 at room temperature pyrrolo[3,2-c]azepin-4-ones are formed.
Efficient and simple zinc-mediated synthesis of 3-amidoindoles
作者:Anahit Pews-Davtyan、Matthias Beller
DOI:10.1039/c1ob05576c
日期:——
A general synthesis of 3-amidoindoles from easily available arylhydrazines and acylated propargylamines is described. In the presence of inexpensive Zn salts, alkyne amination and subsequent Fischer indole-cyclization took place in good yields with excellent regioselectivity providing an interesting scaffold for potentially bio-active compounds.
Preparation of oxazolines and oxazoles<i>via</i>a PhI(OAc)<sub>2</sub>-promoted cyclization of<i>N</i>-propargylamides
作者:Wei Yi、Qing-Yun Liu、Xing-Xiao Fang、Sheng-Chun Lou、Gong-Qing Liu
DOI:10.1039/c8ob01474d
日期:——
A metal-free cyclization of N-propargylamides for the synthesis of various oxazolines and oxazoles via a 5-exo-dig process is presented. Using (diacetoxyiodo)benzene (PIDA) as a reaction promoter and lithium iodide (LiI) as an iodine source, intramolecular iodooxygenation of N-propargylamides proceeded readily, leading to the corresponding (E)-5-iodomethylene-2-oxazolines in good to excellent isolated
Synthesis of Hydroxypyrrolone Carboxamides Employing Selectfluor
作者:Tim Carlo Allmann、Rares-Petru Moldovan、Peter G. Jones、Thomas Lindel
DOI:10.1002/chem.201503695
日期:2016.1.4
Reaction of pyrrole‐2‐carboxamides with Selectfluor in MeCN/water (4:1) affords 2‐hydroxy‐5‐oxopyrrole‐2‐carboxamides in yields of up to 80 %. A variety of sensitive functional groups is tolerated, among them aldehydes and alkynes. The new method also works in the presence of allyl groups and appears to be superior to the use of singlet oxygen. Reaction of the monobrominated dihydropyrrolo[1,2‐a]pyrazinone
Inhibition of Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa biofilm formation with a class of TAGE-triazole conjugates
作者:Robert W. Huigens III、Steven A. Rogers、Andrew T. Steinhauer、Christian Melander
DOI:10.1039/b817926c
日期:——
A chemically diverse library of TAGE-triazole conjugates was synthesized utilizing click chemistry on the TAGE scaffold. This library of small molecules was screened for anti-biofilm activity and found to possess the ability of inhibiting biofilm formation against Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa. One such compound in this library demonstrated the most potent inhibitory effect against Staphylococcus aureus biofilm formation that has been displayed by any 2-aminoimidazole derivative.
利用 TAGE 支架上的点击化学,合成了一个具有化学多样性的 TAGE 三唑共轭物库。对该小分子化合物库进行了抗生物膜活性筛选,发现其具有抑制鲍曼不动杆菌、金黄色葡萄球菌和铜绿假单胞菌形成生物膜的能力。该化合物库中的一个化合物对金黄色葡萄球菌生物膜形成的抑制作用是所有 2-氨基咪唑衍生物中最强的。