21236-85-1

Upstream product

• 2973-27-5 quinoline-4-carbonitrile 
• 2508-86-3 4-aminoquinoline 1-oxide 

Downstream Products

• 100517-53-1 3-hydroxy-quinoline-4-carbonitrile 
• 63158-99-6 2-oxo-1,2-dihydro-quinoline-4-carbonitrile 
• 63158-99-6 2-hydroxy-quinoline-4-carbonitrile 
• 2973-26-4 2-phenyl-4-quinolinecarbonitrile 
• 29312-45-6 1-oxy-2-phenyl-quinoline-4-carbonitrile 
• 74831-35-9 C₂₂H₁₅N₂O 
• 379722-76-6 2-methoxy-4-cyanoquinoline 1-oxide 
• 118-13-8 3-hydroxyquinoline-4-carboxylic acid 
• 74831-37-1 1-Hydroxy-2,2-diphenyl-1,2-dihydro-quinoline-4-carbonitrile 

Relevant academic research and scientific papers

From Pyridine- N-oxides to 2-Functionalized Pyridines through Pyridyl Phosphonium Salts: An Umpolung Strategy

The reactions of pyridine-N-oxides with Ph3P under the developed conditions provide an unprecedented route to (pyridine-2-yl)phosphonium salts. Upon activation with DABCO, these salts readily serve as functionalized 2-pyridyl nucleophile equivalents. This umpolung strategy allows for the selective C2 functionalization of the pyridine ring with electrophiles, avoiding the generation and use of unstable organometallic reagents. The protocol operates at ambient temperature and tolerates sensitive functional groups, enabling the synthesis of otherwise challenging compounds.

Reaction of Pyridine-N-Oxides with Tertiary sp2-N-Nucleophiles: An Efficient Synthesis of Precursors for N-(Pyrid-2-yl)-Substituted N-Heterocyclic Carbenes

N-(Pyrid-2-yl)-substituted azolium and pyridinium salts, precursors for hybrid NHC-containing ligands, were obtained with excellent regioselectivity, employing a deoxygenative CH-functionalization of pyridine-N-oxides with substituted imidazoles, thiazoles, and pyridine. Unlike the traditional SNAr-based methods, this approach provides high yields for substrates bearing substituents of different electronic nature. The utility of azolium and pyridinium salts thus prepared was also highlighted by the synthesis of pyridyl-substituted imidazolyl-2-thione, benzodiazepine as well as 2-aminopyridines.

Dehydrogenative etherification homocoupling of heterocyclic N-oxides

A novel approach was developed for the dehydrogenative etherification homocoupling of heterocyclic N-oxides in the presence of silver oxide and PyBroP. Various substrates were well tolerated and the desired products were obtained in moderate to good yields. Generally, this reaction features excellent functional group compatibility, broad substrate scope and good regioselectivity.

Quaternary N-(2-Pyridyl)-DABCO Salts: One-Pot in Situ Formation from Pyridine-N-oxides and Reactions with Nucleophiles: A Mild and Selective Route to Substituted N-(2-Pyridyl)-N′-ethylpiperazines

The N-(2-pyridyl)-N′-ethylpiperazines are important structural motifs in several medicinally relevant compounds. Known synthetic methods toward these structures are multistep and generally based on the SNAr-chemistry; their applicability is significantly limited to substrates containing electron-withdrawing groups. Here, we describe a new methodology for a rapid and modular access to this privileged scaffold. Importantly, the developed protocol proved to be very general and efficient for the substrates containing substituents of different electronic nature. An operationally simple, metal-free, one-pot synthetic procedure involves the initial reaction of activated heterocyclic N-oxides with DABCO, followed by in situ treatment of the resultant quaternary N-(2-pyridyl)-DABCO salts with nucleophiles, resulting in ring-opening. The method features mild reaction conditions, high positional selectivity, and excellent functional-group tolerance. The utility of our approach is demonstrated by the late-stage site-selective functionalizations of complex molecules; a rapid modular assembly of MC2050, a potent PARP-1 inhibitor; and gram-scale preparations.