1235478-91-7Relevant academic research and scientific papers
Synthesis of isoquinolones: Via Rh-catalyzed C-H activation of substituted benzamides using air as the sole oxidant in water
Upadhyay, Nitinkumar Satyadev,Thorat, Vijaykumar H.,Sato, Ryota,Annamalai, Pratheepkumar,Chuang, Shih-Ching,Cheng, Chien-Hong
supporting information, p. 3219 - 3224 (2017/07/28)
Most of the metal-catalyzed C-H activation/annulation reactions were carried out in organic solvents using expensive oxidants such as Cu(ii) and Ag(i) salts. Here, we reported a new approach for a highly regioselective synthesis of isoquinolones from N-alkyl benzamides and alkynes using an Rh(iii) catalyst and inexpensive oxygen as the sole oxidant in an aqueous medium. In the reaction, water gave the highest product yield among the solvents used. In addition, at the end of the reaction, the isoquinolone product directly precipitated out from the aqueous solution. The methodology can be applied to a gram scale synthesis. This Rh(iii)-catalyzed reaction shows interesting meta selectivity with the meta substituted benzamide and shows various regioselectivities with different substituted alkynes. Moreover, the methodology can be applied to the preparation of biologically active compounds having the isoquinolone core.
Pd/C-catalyzed synthesis of N-aryl and N-alkyl isoquinolones via C[sbnd]H/N[sbnd]H activation
Shu, Zhen,Guo, Yuntao,Li, Wei,Wang, Baiquan
, p. 292 - 297 (2017/09/30)
Pd/C-catalyzed direct synthesis of N-aryl and N-alkyl isoquinolones was developed via the annulation reactions of benzamides and alkynes in high yields (up to 99%) through the cleavage of C[sbnd]H/N[sbnd]H bonds. The reaction was ligand-free and air was used as oxidant. High regioselectivities were found when unsymmetrical alkynes or meta-benzamides were used as substrates. The heterocyclic carboxamide substrates, such as furan and thiophene derivatives, also afforded the corresponding products in high yields.
Rhodium-catalyzed oxidative cycloaddition of benzamides and alkynes via C-H/N-H activation
Hyster, Todd K.,Rovis, Tomislav
supporting information; experimental part, p. 10565 - 10569 (2010/09/17)
The oxidative cycloaddition of benzamides and alkynes has been developed. The reaction utilizes Rh(III) catalysts in the presence of Cu(II) oxidants, and is proposed to proceed by N-H metalation of the amide followed by ortho C-H activation. The resultant rhodacycle undergoes alkyne insertion to form isoquinolones in good yield. The reaction is tolerant of extensive substitution on the amide, alkyne, and arene, including halides, silyl ethers, and unprotected aldehydes as substituents. Unsymmetrical alkynes proceed with excellent regioselectivity, and heteroaryl carboxamides are tolerated leading to intriguing scaffolds for medicinal chemistry. A series of competition experiments shed further light on the mechanism of the transformation and reasons for selectivity.
