Site-Selective C8-Alkylation of Quinoline N-Oxides with Maleimides under Rh(III) Catalysis

Abstract

The site-selective modification of quinolines and their analogs has emerged as a pivotal topic in medicinal chemistry and drug discovery. Herein, we describe the rhodium­(III)-catalyzed C8-alkylation of quinoline N-oxides with maleimides as alkylating agents, resulting in the formation of bioactive succinimide-containing quinoline derivatives. The reaction proceeds under mild conditions with complete functional group tolerance.

Transition-Metal-Catalyzed Directed C8–H Carbon–Carbon Bond Formation in Quinolines and 1,2,3,4-Tetrahydroquinolines

“…Concurrently, Kim group achieved the C8-alkylation of QNOs with maleimides using Scheme 9 Regioselective C8-alkylation of THQs 2.5 mol % Cp*Rh(III) complex, 10 mol % AgSbF6 and PivOH in HFIP (Scheme 8C). 31 The procedure is compatible with diverse functionalities on QNOs and maleimides. L-Alanine ester derived maleimide delivers the product in 98% yield, while N-allylated maleimide gives a decreased yield.…”

Maleimides in Directing‐Group‐Controlled Transition‐Metal‐Catalyzed Selective C−H Alkylation

“…Recently, Kim and Mishra reported the Rh(III)‐catalyzed C8‐alkylation of quinoline N ‐oxides with maleimides, affording a variety of bioactive succinimide‐containing quinoline derivatives (Scheme 27). [33a] To elucidate the plausible reaction mechanism, a rhodacycle complex was synthesized which proved to be an efficient catalyst toward this reaction. Almost simultaneously, Sharma disclosed the similar transformation, in which free maleimide and acrylates were all compatible substrates, although higher catalyst loading was needed (Scheme 27).…”

Cobalt phthalocyanine (CoPc) anchored on Ti3C2 MXene nanosheets for highly efficient selective catalytic oxidation

“…Hence, Ti 3 C 2 MXene could be applied as the solid support for CoPc, increasing its uniform distribution and anchoring impact in Ti 3 C 2 , as well as its catalytic capability. [23][24][25] The attempt to produce quinclorac with molecularly dispersed metal phthalocyanine catalysts in the presence of molecular oxygen has never been reported, to the best of our knowledge. [26][27][28][29] In this work, we report the realization of quinclorac synthesis enabled by anchoring CoPc onto Ti 3 C 2 MXene nanosheets for the design of a new kind of CoPc/Ti 3 C 2 -Mn(OAc) 2 -HBr (CoPc/ Ti 3 C 2 -4.5%-Mn-Br) system with oxygen as the oxidant.…”

“…Hence, Ti 3 C 2 MXene could be applied as the solid support for CoPc, increasing its uniform distribution and anchoring impact in Ti 3 C 2 , as well as its catalytic capability. 23–25 The attempt to produce quinclorac with molecularly dispersed metal phthalocyanine catalysts in the presence of molecular oxygen has never been reported, to the best of our knowledge. 26–29…”