نتایج جستجو برای: nitrones
تعداد نتایج: 453 فیلتر نتایج به سال:
Two diastereoisomers of the title compound, C(25)H(26)N(2)O, have been prepared by cyclo-addition between 1,3,3-trimethyl-2-methyl-eneindoline and C-phenyl-N-phenyl-nitrone. The stereochemistry of the major diastereoisomer, viz. S,R/R,S, is confirmed by the X-ray analysis. The oxazole and the pyrole rings have envelope conformations. The packing is stabilized by weak C-H⋯π inter-actions involvi...
Z. Naturforsch. 61b, 431 – 436 (2006); received January 17, 2006 The 3,4-substituted 2-oxo-piperazines 5 – 9 are obtained by [3+2] cycloaddition from nitrone 1 and a variety of alkenes. Subsequent functionalization of the bicyclic adducts involves reductive N-O bond cleavage. A route towards libraries of immobilized 1,3-aminoalcohols with a 3,4-substituted 2-oxo-piperazine scaffold is briefly d...
The regioselective intramolecular 1,3-dipolar cycloaddition of the phenylsulfonylallene-nitrone derivatives has been developed. This reaction showed that the distal double bond of the allene exclusively reacted with the nitrone group to produce the bicyclic isoxazolidine derivatives regardless of the substitution pattern on the allenyl moiety.
Described is the construction of the N-methylwelwitindolinone C core via an efficient strategy that employs a sequential rhodium carbenoid-mediated O-H insertion, Claisen rearrangement and transannular [3+2] nitrone cycloaddition.
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