Functionalization of 1,3,4-Oxadiazoles and 1,2,4-Triazoles via Selective Zincation or Magnesiation Using 2,2,6,6-Tetramethylpiperidyl Bases
作者:Kuno Schwärzer、Carl Phillip Tüllmann、Simon Graßl、Bartosz Górski、Cara E. Brocklehurst、Paul Knochel
DOI:10.1021/acs.orglett.0c00238
日期:2020.3.6
We report the metalation of the 1,3,4-oxadiazole and 1,2,4-triazole scaffolds via regioselective zincation or magnesiation using the TMP bases (TMP = 2,2,6,6-tetramethylpiperidyl) TMP2Zn·2LiCl, TMP2Zn·2MgCl2·2LiCl, TMPMgCl·LiCl, and TMPZnCl·LiCl under mild conditions in THF. Subsequent trapping with various electrophiles including hydroxylamino benzoates gives access to functionalized heterocycles
Catalyst- and Reagent-Free Electrochemical Azole C−H Amination
作者:Youai Qiu、Julia Struwe、Tjark H. Meyer、João C. A. Oliveira、Lutz Ackermann
DOI:10.1002/chem.201802832
日期:2018.9.3
Catalyst‐ and chemical oxidant‐free electrochemical azole C−H aminations were accomplished via cross‐dehydrogenative C−H/N−H functionalization. The catalyst‐free electrochemical C−H amination proved feasible on azoles with high levels of efficacy and selectivity, avoiding the use of stoichiometric oxidants under ambient conditions. Likewise, the C(sp3)−H nitrogenation proved viable under otherwise
A Metal-Free Route to 2-Aminooxazoles by Taking Advantage of the Unique Ring Opening of Benzoxazoles and Oxadiazoles with Secondary Amines
作者:Jomy Joseph、Ji Young Kim、Sukbok Chang
DOI:10.1002/chem.201100910
日期:2011.7.18
Toss an amine into the ring: A new metal‐free protocol for the amination of oxazoles has been developed by using iodobenzene diacetate to couple various oxazoles with amines (see scheme). The reaction proceeds through a ring‐opening and subsequent ring‐closing pathway. The optimal conditions are very mild and the substrate scope is broad, producing a range of 2‐aminooxazoles, an important pharmacophore
Chloroamine serves as an efficient amination reagent to the heteroaromatic C-H bond of azole under copper catalysis even at room temperature. This catalysis enables a rapid and concise construction of aminoazoles of great interest in biological and medicinal chemistry.