A transition-metal-free synthesis of pyridine derivatives by 6-endo-dig cyclization of N-propargyl enamines was developed. This method is environmentally friendly and is a high atom economy reaction that is easily accessed to provide pyridine derivatives in moderate to good yield by heating N-propargyl enamines in solvent without additives. The total synthesis of onychine was achieved in 51% yield
establishment of some acid-acid-catalyzed tandem reactions. Addition of MB to acid-catalyzed reaction system not only allowed the use of some basic amines as substrates, which are generally incompatible with the acid conditions, but also enabled the successful synthesis of many important nitrogen-containing heterocycles, such as β-carbolines, pyridines, and quinazolines, in a straightforward manner.
The present invention relates to substituted 1,3,8-triazaspiro[4.5]decame-2,4-diones useful as HIF prolyl hydroxylase inhibitors to treat anemia and like conditions.