A concise synthesis of indoloquinoline skeletons applying two consecutive Pd-catalyzed reactions

A General and Efficient Synthesis of 2‐Pyridones, 2‐Quinolinones, and 1‐Isoquinolinones from Azine N‐Oxides

“…Although mild and high‐yielding halogenation methods have recently been developed by our group and others, extra halogenation steps are still required. Alternatively, the treatment of N ‐oxides (i.e., 1 ) with an activating agent [A‐Y=ClCO 2 CH 2 CH 3 , PhCOCl, TsCl (Ts= para ‐toluenesulfonyl)] enhances the electrophilic character of the 2‐position (i.e., 5 ), which allows for nucleophilic addition to give 2‐substituted product 3 (Scheme B). Such Reissert–Henze‐type reactions, however, are not broadly applicable and only work for a limited number of quinolone and isoquinoline N ‐oxides .…”

Synthesis of Benzoacridines and Benzophenanthridines by Regioselective Pd‐Catalyzed Cross‐Coupling Reactions Followed by Acid‐Mediated Cycloisomerizations

“…The starting materials, 3‐bromo‐2‐iodoquinoline ( 1 ) and 4‐bromo‐3‐iodoquinolines 8a , b , were prepared according to previously reported procedures (Scheme ) . Subsequently, chemoselective Suzuki reactions of 1 with various arylboronic acids were carried out, followed by Sonogashira reaction in position 3 (Scheme ).…”

“…Pharmacologically important acridines and phenanthridines.[a]The starting materials, 3-bromo-2-iodoquinoline (1) and 4bromo-3-iodoquinolines 8a,b, were prepared according to previously reported procedures (Scheme 1). [21] Subsequently, chemoselective Suzuki reactions of 1 with various arylboronic acids were carried out, followed by Sonogashira reaction in position 3 (Scheme 2). Due to the better leaving group ability of iodide as compared to bromide, the Suzuki reaction of 1 proceeds chemoselectively at the carbon-iodine bond to give 2aryl-3-bromoquinolines 2a-f in 65-77 % yield.…”

“…IR (ATR, cm -1 ): ν = 3056 (w), 3030 (w), 2923 (w), 2212 (w), 1596 (w), 1570 (w), 1479 (m), 1442 (m), 1413 (m), 1368 (m), 911 (m), 769 (m), 750 (s), 718 (m), 695 (m), 686 (s), 533 (m), 477 (m). MS (EI, 70 eV): m/z (%) = 306 (11), 305 ([M] + , 58), 304 (100), 303(21), 302(13), 301(7), 200(7), 152 (9), 151(8). HRMS (ESI): Calculated for C23 H 15 N [M + H] + 306.1277 found 306.1273.…”

Neocryptolepine (Cryprotackieine), A Unique Bioactive Natural Product: Isolation, Synthesis, and Profile of Its Biological Activity

“…[69] An approach similar to that of Maes was followed by Bóganyi and Kámán (Scheme 17), starting from 3-bromo-2-iodoquinoline (105), easily available from 3-bromoquinoline (92) through the intermediacy of 3-bromo-1H-quinolin-2-one (94). [73] They devised a two-step strategy based on microwave-assisted palladium chemistry and entailing a regioselective Buchwald-Hartwig amination of the quinoline 105 with aniline under Xantphos-Pd(OAc) 2 The activation of C-H bonds by dirhodium(II) carbenoids and nitrenoids allows access to valuable carbocycles and heterocycles efficiently and stereoselectively. [74] Driver's group recently reported a study of the Rh 2 II -catalyzed synthesis of various heterocycles by taking advantage of rhodium-mediated controlled decomposition of aryl and vinyl azides.…”