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Bismuth(III) Reagents in Steroid and Terpene Chemistry
Salvador, Jorge A. R.; Silvestre, Samuel M.; Pinto, Rui M. A.Steroid and terpene chemistry still have a great impact on medicinal chemistry. Therefore, the development of new reactions or “greener” processes in this field is a contemporaneous issue. In this review, the use of bismuth(III) salts, as “ecofriendly” reagents/catalysts, on new chemical processes involving steroids and terpenes as substrates will be focused. Special attention will be given to some mechanistic ...
Metal triflates combined with caffeine based imidazolium salts: A new family of...
Pinto, Rui M. A.; Salvador, Jorge A. R.; Roux, Christophe LeThe direct alkylation of caffeine (1), by ethyl triflate gave 1,3,7-trimethyl-9-ethylxanthinium triflate (2) which led to 1,3,7-trimethyl-9-ethylxanthinium bis(trifluoromethanesulfonyl)amide (3) after methathesis with LiNTf2; 3 proved to be an ionic solid which can be used for the recovery of metal triflates (M(OTf)n with M = Sc, La, Yb, Cu, Hf, Bi). These reusable catalysts proved to be efficient Lewis acids f...
5β,6β-Epoxy-17-oxoandrostan-3β-yl acetate and 5β,6β-epoxy-20-oxopregnan-3β-yl a...
Pinto, Rui M. A.; Salvador, Jorge A. R.; Paixão, José A.In the title compounds, C21H30O4, (I), and C23H34O4, (II), respectively, which are valuable intermediates in the synthesis of important steroid derivatives, rings A and B are cis-(5β,10β)-fused. The two molecules have similar conformations of rings A, B and C. The presence of the 5β,6β-epoxide group induces a significant twist of the steroid nucleus and a strong flattening of the B ring. The different C17 subst...
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