A Convenient Synthetic Route for Substituted 1-(Aryldiazenyl)Imidazo[1,5-a]Pyridine
摘要:
In the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), model 2-(N'-aryl)picolinohydrazonamides 7, 8 (derived from interaction of the respective ethyl glycinate and (2-pyridyl)methylamine with the particular hydrazonoyl chloride) underwent didehydrogenation with concomitant heterocyclization to deliver the corresponding 1-(aryldiazenyl)imidazo[1,5-a]pyridines 9, 10. Structures of the latter bicyclic systems are deduced from spectral data and confirmed by X-ray diffraction analysis of the Pd-complex 11, derived from 9.
Fast Alpha Nucleophiles: Structures that Undergo Rapid Hydrazone/Oxime Formation at Neutral pH
摘要:
Hydrazones and oximes are widely useful structures for conjugate formation in chemistry and biology, but their formation can be slow at neutral pH. Kinetics studies were performed for a range of structurally varied hydrazines, and a surprisingly large variation in reaction rate was observed. Structures that undergo especially rapid reactions were identified, enabling reaction rates that rival orthogonal cycloaddition-based conjugation chemistries.