Synthetic applications of N-carboalkoxysulfamate esters
01 Aug 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 17, pp 5224-5226
About: This article is published in Journal of the American Chemical Society.The article was published on 1970-08-01. It has received 89 citations till now.
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TL;DR: In this article, cyclization of serine and threonine derivatives with Burgess reagent provides a one-step, streospecific access to 4,5-dihydrooxazoles.
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TL;DR: In this article, the authors exploited β-hydride elimination to accomplish palladium-catalyzed dehydrohalogenations of alkyl bromides to form terminal olefins.
Abstract: We have exploited a typically undesired elementary step in cross-coupling reactions, β-hydride elimination, to accomplish palladium-catalyzed dehydrohalogenations of alkyl bromides to form terminal olefins. We have applied this method, which proceeds in excellent yield at room temperature in the presence of a variety of functional groups, to a formal total synthesis of (R)-mevalonolactone. Our mechanistic studies have established that the rate-determining step can vary with the structure of the alkyl bromide and, most significantly, that L(2)PdHBr (L = phosphine), an intermediate that is often invoked in palladium-catalyzed processes such as the Heck reaction, is not an intermediate in the active catalytic cycle.
99 citations
TL;DR: The synthetic route features an efficient carboannulation sequence to rapidly access the dihydroindenone system and a series of Au(I)-catalyzed transformations served in the construction of the sterically congested core framework.
Abstract: Revised version: the first total synthesis of indoxamycin B leads to a stereochemical reassignment of the natural product. The synthetic route features an efficient carboannulation sequence to rapidly access the dihydroindenone system. Moreover, a series of Au(I)-catalyzed transformations served in the construction of the sterically congested core framework.
71 citations
TL;DR: A new route to 24-nortriterpene derivatives with 2-hydroxy-Delta(1,4)-cyclohexadien-3-one A-rings from triterpene precursors has been demonstrated beginning with betulin to prepare derivatives of betulinic acid.
Abstract: A new route to 24-nortriterpene derivatives with 2-hydroxy-Δ1,4-cyclohexadien-3-one A-rings from triterpene precursors has been demonstrated beginning with betulin to prepare derivatives of betulin...
58 citations
TL;DR: The synthesis, SAR, and preclinical evaluation of 17-cyanated 2-substituted estra-1,3,5(10)-trienes as anticancer agents are discussed, and it is revealed that a sterically unhindered hydrogen bond acceptor attached to C-17 is most likely key to the enhanced activity.
Abstract: The synthesis, SAR, and preclinical evaluation of 17-cyanated 2-substituted estra-1,3,5(10)-trienes as anticancer agents are discussed. 2-Methoxy-17β-cyanomethylestra-1,3,5(10)-trien-3-ol (14), but not the related 2-ethyl derivative 7, and the related 3-O-sulfamates 8 and 15 display potent antiproliferative effects (MCF-7 GI50 300, 60 and 70 nM, respectively) against human cancer cells in vitro. Investigation of the SAR reveals that a sterically unhindered hydrogen bond acceptor attached to C-17 is most likely key to the enhanced activity. Compound 8 displayed significant in vitro antiangiogenic activity, and its ability to act as a microtubule disruptor was confirmed. Inhibitory activity of the sulfamate derivatives against steroid sulfatase and carbonic anhydrase II (hCAII) was also observed, and the interaction between 15 and hCAII was investigated by protein crystallography. The potential of these multimechanism anticancer agents was confirmed in vivo, with promising activity observed for both 14 and ...
49 citations