نتایج جستجو برای: beckmann type rearrangement
تعداد نتایج: 1365510 فیلتر نتایج به سال:
1-(2-Alkynylphenyl)ketoximes react with Lawesson's reagent catalyzed by InCl(3) and cyanuric chloride leading to 4-methylene-4H-benzo[d][1,3]thiazines in good yields. This tandem reaction proceeds with high efficiency through Beckmann rearrangement, thioamide formation, and intramolecular nucleophilic cyclization.
Substituted pyrrolines are available by ring closure initiated by direct nucleophilic attack of stabilized enolates at the nitrogen of oximes activated with a leaving group, in a process which effectively out-competes the more usual Beckmann rearrangement. Subsequent reduction provides diastereoselective access to the corresponding pyrrolidines. This provides a rapid route to saturated heterocy...
The synthesis of visnaginone-oxime (2 a) and khellinone-oxime (2 b) is reported. Beckmann rearrangement of 2 a and 2b using different cyclising agents was studied. Structure assignement for the produced benzoxazole derivatives and benzisoxazole derivatives was confirmed by chemical and spectral evidences. Utilization of visnaginone (la) and khellinone (lb) for the synthesis of new furoflavone d...
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