Although they are not pyridines, the Hantzsch synthesis of these compounds is a common way to produce them.
In a reaction synthesizing these compounds, a ketoxime reacts with an electron-deficient alkyne to generate a compound that can undergo a [3,3]-sigmatropic rearrangement. That is the Trofimov synthesis. The reaction of two equivalents of an aldehyde and a hydrazine can form one of these compounds with substituents at the 3 and 4-positions, that is the Piloty-Robinson synthesis. The most well-known synthesis of these compounds requires one to react a primary amine with a 1,4-diketone; this is the Paal-Knorr synthesis. Although they are not pyridines, the Hantzsch synthesis of these compounds is a common way to produce them. These compounds have an unusually low basicity due to the nitrogen lone pair donation into the conjugated ring to maintain aromaticity. Name these compounds, which have a resonance energy intermediate between thiophenes and furans, characterized by a five-membered nitrogen-containing heterocycle.
In a reaction synthesizing these compounds, a ketoxime reacts with an electron-deficient alkyne to generate a compound that can undergo a [3,3]-sigmatropic rearrangement.
pyrroles