7063-98-1Relevant articles and documents
Transition-Metal-Free Multicomponent Approach to Stereoenriched Cyclopentyl-isoxazoles through C?C Bond Cleavage
Subramanian, Parthasarathi,Kaliappan, Krishna P.
, p. 2031 - 2039 (2018)
An efficient multicomponent reaction for the synthesis of stereoenriched cyclopentyl-isoxazoles from camphor-derived α-oximes, alkynes, and MeOH is reported. Our method involved a series of cascade transformations, including the in situ generation of an IIII catalyst, which catalyzed the addition of MeOH to a sterically hindered ketone. Oxidation of the oxime, and rearrangement of the α-hydroxyiminium ion generated a nitrile oxide in situ, which, upon [3+2] cycloaddition reaction with an alkyne, delivered the regioselective product. This reaction was very selective for the syn-oxime. This multicomponent approach was also extended to the synthesis of a new glycoconjugate, camphoric ester-isoxazole C-galactoside.
Synthetic Diversity from a Versatile and Radical Nitrating Reagent
Zhang, Kun,Jelier, Benson,Passera, Alessandro,Jeschke, Gunnar,Katayev, Dmitry
supporting information, p. 12929 - 12939 (2019/09/17)
We leverage the slow liberation of nitrogen dioxide from a newly discovered, inexpensive succinimide-derived reagent to allow for the C?H diversification of alkenes and alkynes. Beyond furnishing a library of aryl β-nitroalkenes, this reagent provides unparalleled access to β-nitrohydrins and β-nitroethers. Detailed mechanistic studies strongly suggest that a mesolytic N?N bond fragmentation liberates a nitryl radical. Using in situ photo-sensitized, electron paramagnetic resonance spectroscopy, we observed direct evidence of a nitryl radical in solution by nitrone spin-trapping. To further exhibit versatility of N-nitrosuccinimide under photoredox conditions, the late-stage diversification of an extensive number of C?H partners to prepare isoxazolines and isoxazoles is presented. This approach allows for the formation of an in situ nitrile oxide from a ketone partner, the presence of which is detected by the formation of the corresponding furoxan when conducted in the absence of a dipolarophile. This 1,3-dipolar cycloaddition with nitrile oxides and alkenes or alkynes proceeds in a single-operational step using a mild, regioselective, and general protocol with broad chemoselectivity.
The branch part and delivery system, the catheter assembly
-
, (2007/10/08)
A catheter assembly including a side branch locator that is moveable between a retracted position within a main vessel of a vessel bifurcation, and an extended position wherein a distal end of the side branch locator extends into a branch vessel of the vessel bifurcation. The side branch locator includes a first end fixed relative to a portion of the catheter assembly that remains in the main vessel. A second end of the side branch locator is moveable between the retracted and extended positions. The catheter assembly can include a moveable sheath that holds the side branch locator in the retracted position. The catheter assembly can further include a stent having a lateral branch opening through which the side branch locator extends.