Synthesis and Reactivity of Imide-Derived Bisvinyl Phosphates. Reactivity of 2,6-Disubstituted 1,4-Dihydropyridines
摘要:
Symmetrical and unsymmetrical 2,6-disubstituted dihydropyridines were prepared in high yields under mild conditions using the Suzuki and Stille Pd-catalyzed coupling reactions of imide-derived bisvinyl phosphates with a range of aryl, heteroaryl, and alkenyl moieties. The alkylation reaction at C-4 easily afforded original tri- and tetrasubstituted dihydropyridines. Hydrolysis of the latter under acidic condition provided efficiently either open-chain 1,5-diketones or di- or trisubstituted pyridines.
Mechanism-based design of simple, symmetrical, easily prepared, potent antimalarial endoperoxides
作者:Gary H. Posner、Dasong Wang、Lluïsa González、Xueliang Tao、Jared N. Cumming、Donna Klinedinst、Theresa A. Shapiro
DOI:10.1016/0040-4039(95)02329-1
日期:1996.2
Mechanism-based design, two-step synthesis, and in vitro antimalarial testing showed thermally stable, crystalline, bicyclic endoperoxides 2a and 2b to be potent antimalarials. Their reduction by FeBr2 proceeds via oxy-radicals and then carbon radicals that undergo β-scission to form an alkene and a high-valent FeO species.
reported earlier. Obviously, the alkyl groups at the 4-positions of the 4 H -thiopyrans strongly diminish the efficiency of the di-π-methane rearrangement and, contrastingly, a four-electron suprafacial [1,3]-sigmatropic rearrangement is found to be highly efficient.