title: Aromatic nucleophilic substitution or CuI-catalyzed coupling route to martinellic acid.
abstract: Condensation of beta-amino ester 8b with triflate 7 gives N-aryl amino ester 11, which is converted into 2-substituted 4-oxoquinoline 4 using an intramolecular Dieckmann reaction as the key step. CuI-mediated coupling of beta-amino ester 8a with 1,4-diiodobenzene followed by an intramolecular acylation and Pd-catalyzed carbonylation provide another manner to 4. Alkylation of 4 and subsequent reductive amination deliver the cyclic imine 14, which is transformed into triamine 3 by ordinary operations. Guanylation of 3 under mild condition followed by deprotection results in the synthesis of martinellic acid 1.
authors.affiliation: State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, China. madw@pub.sioc.ac.cn
authors.forename: Dawei
authors.initials: D
authors.lastname: Ma
authors.forename: Chengfeng
authors.initials: C
authors.lastname: Xia
authors.forename: Jiqing
authors.initials: J
authors.lastname: Jiang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
authors.forename: Wenjun
authors.initials: W
authors.lastname: Tang
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D000478:Alkylation; D000588:Amines / Q000737:chemistry; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003300:Copper; D018360:Crystallography, X-Ray; D006146:Guanidines / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010165:Palladium; D011758:Pyrroles / Q000138:chemical synthesis*; D011804:Quinolines / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D000588:Amines; D006146:Guanidines; D011758:Pyrroles; D011804:Quinolines; C432345:martinellic acid; D010165:Palladium; D003300:Copper