In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Diastereoselective Synthesis of Pyrazolines by Metal-Free Rearrangement of Bicyclic Triazolines, published in 2020-10-31, which mentions a compound: 3393-45-1, Name is 5,6-Dihydro-2H-pyran-2-one, Molecular C5H6O2, Safety of 5,6-Dihydro-2H-pyran-2-one.
The metal-free preparation of diazoalkanes through the ring rearrangement of bicyclic triazolines was reported. Their use in 1,3-dipolar cycloaddition reactions with electron-withdrawing alkenes was investigated. This synthetic procedure allows differently substituted pyrazolines to be obtained in few steps and with high atom economy.
The article 《Diastereoselective Synthesis of Pyrazolines by Metal-Free Rearrangement of Bicyclic Triazolines》 also mentions many details about this compound(3393-45-1)Safety of 5,6-Dihydro-2H-pyran-2-one, you can pay attention to it, because details determine success or failure
Reference:
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI