2 research outputs found
Synthesis of 2,5-Bis(spirocyclohexane)-Substituted Nitroxides of Pyrroline and Pyrrolidine Series, Including Thiol-Specific Spin Label: An Analogue of MTSSL with Long Relaxation Time
The nitroxides of 7-azadispiro[5.1.5.2]Âpentadecane and
7-azadispiro[5.1.5.2]Âpentadeca-14-ene
series have been prepared, including thiol-specific methane thiosulfonate
spin label for site-directed spin labeling. The effect of spirocyclohexane
moieties on chemical and spectral properties has been studied. The
obtained temperature dependencies of electron spin relaxation parameters
demonstrate that new nitroxides may be suitable for PELDOR distance
measurements at 80–120 K. Moreover, the new nitroxides demonstrated
much higher stability toward reduction by ascorbate than spirocyclohexane-substituted
nitroxides of piperidine series and showed 1.3–3.14 times lower
reduction rates compared to corresponding 2,2,5,5-tetramethyl nitroxides
Base-Catalyzed Domino Cyclization of Acetylenes with Ketones to Functionalized Cyclopentenes
Acetylene reacts with methylarylÂ(hetaryl)Âketones
in the presence
of 6.5 mol % KOH in DMSO to give diastereoselectively in single operationally
functionalized cyclopentenes. This domino cyclization involving two
molecules of acetylene and two molecules of ketone proceeds with the
formation of four C–C bonds. The complementary assembly of
the cyclopentenes with similar functionalities from acetylenes and
1,5-diketones has been developed