I2-mediated oxidative C-N bond formation for metal-free one-pot synthesis of di-, tri-, and tetrasubstituted pyrazoles from α,β-unsaturated aldehydes/ketones and hydrazines
An I2-mediated metal-free oxidative C-N bond formation methodology has been established for the regioselective pyrazole synthesis. This practical and eco-friendly one-pot protocol requires no isolation of the less stable intermediates hydrazone
Functionalized 4-aminoquinolines by rearrangement of pyrazole N-heterocyclic carbenes
(Figure Presented) Thermal decarboxylation of 1-phenyl pyrazolium-3- carboxylates from the mesomeric betaine class of substances leads to pyrazole-N-heterocyclic carbenes, which immediately rearrange to multiply substituted 4-aminoquinolines (see scheme). These species are of interest for the synthesis of heterocycles and pharmacologically active compounds.