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- Heteroaromatic benzyl ethers as intermediates for palladium-catalysed transfer hydrogenolysis of benzyl alcoholsPublication . Araujo, Nuna C. P.; Brigas, Amadeu; Cristiano, Maria Lurdes Santos; Frija, L.; Guimarães, Emanuel M. O.; Loureiro, Rui M. S.A chemoselective and easy to carry procedure for the hydrogenolysis of benzyl alcohols is described. Benzyl alcohols are readily converted into tetrazolyl and benzisothiazolyl ethers that can be catalytically hydrogenolysed to toluenes over palladium-on-charcoal using hydrogen donors. The effect of electronwithdrawing heteroaromatic substituents is interpreted on the basis of chrystallographic structure determinations and molecular orbital calculations.
- Structural effects on sigmatropic shifts in heteroaromatic allyl ethersElectronic supplementary information (ESI) available: selected crystal data for compound 7. See http://www.rsc.org/suppdata/p1/b1/b102674g/Publication . Araujo, Nuna C. P.; Barroca, Pedro M. M.; Bickley, Jamie F.; Brigas, Amadeu; Cristiano, Maria Lurdes Santos; Johnstone, Robert A. W.; Loureiro, Rui M. S.; Pena, Paula C. A.In contrast to the known thermal, exclusively [3,3], O- to N- rearrangement of allyl groups in phenyltetrazoles (1, Scheme 1), the comparable migration of the allyl group in pseudosaccharyl ethers (3; Scheme 2) has been shown to proceed through both [1,3]- and [3,3]-mechanisms, 4, 5; for the pseudosaccharyl derivative of the natural product myrtenol (6; Scheme 3) only the product 7 of a [1,3]-shift has been observed; crystallographic data and theoretical calculations provide an explanation of this ease of [1,3]-isomerization and the observed selectivity as being due to conformational constraints and electronic factors.
- Mild liquid-phase Friedel-Crafts acylation of heteroaromatic compounds over zeolite BetaPublication . Álvaro, V. F. D.; Brigas, Amadeu; Derouane, E. G.; Lourenço, J. P.; Santos, Bruna S.Heteroaromatic compounds, such as thiophenes, pyrroles and furans, were acylated using zeolite Beta, with and without modifications, and acetic anhydride. Amenable conditionswere found to carry out these acylations in high yield, sometimes in a very short time (10 min). Indium modified catalyst have provided a way of attaining good yields in the acylation of pyrrole.