230637-90-8Relevant articles and documents
Light-Induced C-H Arylation of (Hetero)arenes by in Situ Generated Diazo Anhydrides
Cantillo, David,Mateos, Carlos,Rincon, Juan A.,De Frutos, Oscar,Kappe, C. Oliver
supporting information, p. 12894 - 12898 (2015/09/07)
Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time.
Synthesis and reactions of 4-hydroxy-2(1H)-pyridones with thienyl and pyridyl substituents in position 6 starting with azomethines and malonates
Schnell, Barbara
, p. 541 - 548 (2007/10/03)
The reaction of 4 with substituted diethyl malonates 5a, or 'magic malonates' (bis-2,4,6-trichlorophenylmalonates 5b) leads to 4-hydroxy-2(1H)- pyridones 6. The azomethines 4 are prepared via the Strecker compounds 3 starting with methyl ketones 1, anilines, and potassium cyanide. Chlorination of pyridones 6 with sulfuryl chloride leads to compounds 7 while nitration gives 9.
