title: Palladium mediated intramolecular multiple C-X/C-H cross coupling and C-H activation: synthesis of carbazole alkaloids calothrixin B and murrayaquinone A.
abstract: Straightforward palladium mediated syntheses of calothrixin B and murrayaquinone A are described. Regioselective palladium mediated intramolecular multiple C-X/C-H cross coupling reaction on N-(4-((2-bromophenyl)amino)-2,5-dimethoxybenzyl)-N-(2-iodophenyl)acetamide followed by CAN oxidation afforded calothrixin B in excellent yield in two steps. A linear synthesis has also been developed for calothrixin B. Utilizing C-H functionalization as well as palladium mediated intramolecular C-X/C-H cross coupling reaction, murrayaquinone A synthesis was achieved. Overall, these synthetic methodologies provide an expedient entry to these biologically active alkaloids in a short reaction sequence.
authors.affiliation: Technology Development Centre, Custom Pharmaceutical Services, Dr Reddy's Laboratories Ltd, Miyapur, Hyderabad, 500 049, India. syam_kmr@yahoo.com.
authors.forename: Srinivasan A
authors.initials: SA
authors.lastname: Kaliyaperumal
authors.forename: Shyamapada
authors.initials: S
authors.lastname: Banerjee
authors.forename: Syam Kumar
authors.initials: SK
authors.lastname: U K
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D000586:Amination; D016227:Benzoquinones / Q000138:chemical synthesis* / Q000737:chemistry*; D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D010165:Palladium
chemical_list: D000470:Alkaloids; D016227:Benzoquinones; D002227:Carbazoles; D026121:Indole Alkaloids; C418327:calothrixin B; C062196:murrayaquinone A; D010165:Palladium