Journal ArticleDOI
Studies of [3,3]sigmatropic rearrangements: rearrangement of 3-(4-p-tolyloxybut-2-ynyloxy)[1]benzopyran-2-one
Krishna C. Majumdar,R. N. De,Abu T. Khan,Shital K. Chattopadhyay,Kamalendu Dey,Amarendra Patra +5 more
TLDR
In this paper, it was shown that refluxing in chlorobenzene, ethyl benzene, or xylene, gave exclusively 1-(p-tolyloxymethyl)pyrano[2,3-c][1]benzopyran-5(3H)-one (2), whereas through an ionic or radical pathway 2-methyl-1-to-loxyloxybut-2-ynyloxy(2, 3-c)furo[2.5]-pyrone-4-one (3Abstract:
3-(4-p-Tolyloxybut-2-ynyloxy)[1]benzopyran-2-one (1), when refluxed in chlorobenzene, ethyl benzene, or xylene, gave exclusively 1-(p-tolyloxymethyl)pyrano[2,3-c][1]benzopyran-5(3H)-one (2), whereas through an ionic or radical pathway 2-methyl-1-(p-tolyloxymethyl)furo[2,3-c][1]benzopyran-4-one (3) was the exclusive product.read more
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Journal ArticleDOI
Synthesis, stereochemistry, structural classification, and chemical reactivity of natural pterocarpans.
Journal ArticleDOI
Studies in sigmatropic rearrangement: synthesis of a [6,6]pyranothiopyran ring system by sequential claisen rearrangement and pyridine hydrotribromide mediated regioselective "6-Endo" cyclization.
TL;DR: 4-(4'-Aryloxybut-2'-ynylthio)[1]benzopyran-2-ones are refluxed in chlorobenzene to afford 4-aryloxymethylthiopyrano[3,2-c]-ones which are subsequently subjected to heating in o-dichlorobenzenes in the presence of N,N-diethylaniline and then treated with pyridine hydrotribromide to give
Journal ArticleDOI
Studies in Pyrimidine-Annelated Heterocycles1 by Tandem Cyclization: Regioselective Synthesis of [6,6]Pyranopyran by Intramolecular [1,6] Michael Addition
K. C. Majumdar,U. Das +1 more
Journal ArticleDOI
Mercury-catalyzed synthesis of heterocycles
TL;DR: In this paper, the synthesis of N-, O- and S-heterocycles has been studied and a number of reports for their synthesis have appeared in recent decades; however, traditional approaches require expensive o...
Journal ArticleDOI
Applications of gold catalysts for the synthesis of five-membered O-heterocycles
TL;DR: A large number of reports related to the synthesis of N-, O-, and S-containing heteocycles have appeared owing to a wide variety of their biological activity as discussed by the authors.