The convergent total synthesis of the manzamine alkaloid (-)-nakadomarin A (1) is described. The retrosynthetic analysis recognized spirocycle 3, assembled via an organocatalyst-promoted Michael addition/cyclization between bicyclic lactam 4 and furan aldehyde 5, both accessible from achiral starting materials and on a multigram scale. Lactam 4 is assembled through an S2'/reduction/Staudinger/retro-aza-Claisen sequence on scale. After spirocyclization, the synthesis of nakadomarin is completed in only six steps.
Perfluorosulfonic acid membrane (Nafion®-117) was first surface modified with atmospheric pressure UV photo-oxidation or low-pressure vacuum UV photo-oxidation downstream from an Ar microwave plasma, and then graft polymerized with acrylic acid. X-ray photoelectron spectroscopy (XPS) was used to analyze the modified Nafion surface and poly(acrylic acid) grafted to the modified surface.
The efficient copper-catalyzed construction of imidazopyridinones is described. Beginning from iodopyridinyl ureas, Ullmann coupling provides imidazopyridinones in good yield. Manufacturing by this process is described on 473 kg scale; the scope and limitations of substrates is also detailed.
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