1,720,977 research outputs found
Paternò-Buechi reaction between furan and heterocyclic aldehydes: oxetane formation vs. metathesis
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Photochemical reactivity of 2-azido-1,3-thiazole and 2-azido-1,3-benzothiazole: a procedure for the aziridination of enol ethers
No full textDirect irradiation of a mixture of the azido–tetrazole tautomers
of 2-azido-1,3-thiazole and 2-azido-1,3-benzothiazole
in toluene solution gives products arising from the intermediate
nitrene, which in turn undergoes ring opening in the case
of 2-azido-1,3-thiazole to give a polymer, and dimerization in
the case of 2-azido-1,3-benzothiazole to give [1,3]benzothiazolo[
2,3:3,4][1,2,4,5]tetraazino[6,1b][1,3]benzothiazole
in low yields. When irradiation is performed in the presence of methyl acrylate or various enol ethers, aziridination of the
double bond is observed, with good yields in the case of enol
ethers. Among these, 1-(6-methyl-3,4-dihydro-2H-pyran-2-
yl)ethanone undergoes aziridination with complete diastereoselectivity
to give the (1RS,3RS,6SR) diastereomer
“A Facile Entry to 4- and 5-Hydroxybenzofuran and their amino derivatives”
No full textAn innovative one-step procedure for the synthesis of 4-hydroxybenzofuran and an improved synthesis of 5-hydroxybenzofuran is reported. Such compounds were also transformed into their amino derivatives via Smiles rearrangement with good to high overall yields
Enzyme-Catalyzed Desymmetrization of meso-Skipped Polyols to Useful Chiral Building Blocks
No full textThe biocatalytic desymmetrization, in presence of different enzymes, of two models of polyfunctionalized diols in a meso form was studied. PFL was found to be the most selective enzyme with excellent results in chemical and optical yield with some of the tested substrates. The obtained chiral building
block was utilized for some useful synthetic transformations toward the synthesis of natural product
A Convergent Preparation of the C1-C13 Fragment of Amphotericin B from a Single Chiral Precursor
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