tracers for positronemissiontomography (PET) and opticalimaging (OI) have emerged as a very promising tool. Indeed, they combine the simplicity of use of optical techniques for in vitro/in vivo pre-clinical studies with the various clinical possibilities offered by PET imaging using their radioactive versions. In this context, the preparation of new tags detectable by fluorescence imaging and potentially
Quinoline derivatives were obtained from enaminones and 2-bromo- or 2-iodobenzaldehydes via copper-catalyzed dominoreactions consisting of the Aldol reaction, C(aryl)-N bond formation and elimination. The electronic effect of aldehydes played a major role in the reaction outcome. Two simple protocols are disclosed to achieve variuos quinolines from both cyclic and acyclic enaminones in good yields
Synthesis of Isoquinolines and Pyridines by the Palladium-Catalyzed Iminoannulation of Internal Alkynes
作者:Kevin R. Roesch、Haiming Zhang、Richard C. Larock
DOI:10.1021/jo0105540
日期:2001.11.1
A wide variety of substituted isoquinoline, tetrahydroisoquinoline, 5,6-dihydrobenz[f]isoquinoline, pyrindine, and pyridine heterocycles have been prepared in good to excellent yields via annulation of internal acetylenes with the tert-butylimines of o-iodobenzaldehydes and 3-halo-2-alkenals in the presence of a palladium catalyst. The best results are obtained by employing 5 mol % of Pd(OAc)(2), an excess of the alkyne, 1 equiv of Na2CO3 as a base, and 10 mol % of PPh3 in DMF as the solvent. This annulation methodology is particularly effective for aryl- or alkenyl-substituted alkynes. When electron-rich imines are employed, this chemistry can be extended to alkyl-substituted alkynes. Trimethylsilyl-substituted alkynes also undergo this annulation process to afford monosubstituted heterocyclic products absent the silyl group.