- Synthesis and reactivity of α-sulfenyl-β-chloroenones, including oxidation and Stille cross-coupling to form chalcone derivatives
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The synthesis of a range of novel α-sulfenyl-β-chloroenones from the corresponding α-sulfenylketones, via a NCS mediated chlorination cascade, is described. The scope of the reaction has been investigated and compounds bearing alkyl- and arylthio substituents have been synthesised. In most instances, the Z α-sulfenyl-β-chloroenones were formed as the major products, while variation of the substituent at the β-carbon position led to an alteration in stereoselectivity. Stille cross-coupling with the Z α-sulfenyl-β-chloroenones led to selective formation of Z sulfenyl chalcones, while the E α-sulfenyl-β-chloroenones did not react under the same conditions. Oxidation of the Z α-sulfenyl-β-chloroenones was followed by isomerisation, leading to the E α-sulfinyl-β-chloroenones. Stille cross-coupling with the E α-sulfinyl-β-chloroenones produced the E sulfinyl chalcones. Either the E or Z sulfinyl chalcones can be obtained by altering the sequence of oxidation and Stille cross-coupling.
- Kearney, Aoife M.,Murphy, Linda,Murphy, Chloe C.,Eccles, Kevin S.,Lawrence, Simon E.,Collins, Stuart G.,Maguire, Anita R.
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supporting information
(2021/05/04)
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- α,α-Alkylation-Halogenation and Dihalogenation of Sulfoxonium Ylides. A Direct Preparation of Geminal Difunctionalized Ketones
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A one-pot alkylation–halogenation of ketosulfoxonium ylides in the presence of alkyl halides is described. The method furnishes several gem-difunctionalized haloketones (an alkyl and F, Cl, Br, or I) in good yields. Replacing alkyl halides with a mixture of electrophilic halogen species and various halide anions led to gem-dihalogenated ketones containing a combination of the same or two different halogens. Kinetic isotopic effects as well as reaction kinetic experiments give insight to the mechanism of these reactions.
- Gallo, Rafael D. C.,Ahmad, Anees,Metzker, Gustavo,Burtoloso, Antonio C. B.
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p. 16980 - 16984
(2017/11/27)
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- N-PHENYLPYRIDONE TYPE III PHOSPHODIESTERASES
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Phosphodiesterase (type III) inhibitors having the formula: which are useful in stimulating cardiac activity and in treating congestive heart failure and bronchoconstriction, pharmaceutical compositions including these inhibitors, and methods of using these compounds to produce phosphodiesterase (type III) inhibition in mammals
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- 6-(substituted phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-ones of medicinal interest. The synthesis of SK&F 94836 and SK&F 95654
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Two synthetic routes to the dihydropyridazinone-cyanoguanidine 4 (SK&F 94836) are described, both proceeding via the anilino compound 6. An efficient synthesis of the dihydropyridazinone-pyridone 5 (SK&F 95654) is reported. This synthesis proceeds via the fluoro-keto-acid 24, with subsequent displacement of the fluoro substituent by 4-pyridone. The surprising effectiveness of water as a solvent in this reaction has been highlighted.
- Burpitt,Crawford,Davies,Mistry,Mitchell,Pancholi,Coates
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p. 1689 - 1695
(2007/10/02)
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