58656-98-7Relevant articles and documents
Enolate-Based Regioselective Anti-Beckmann C-C Bond Cleavage of Ketones
Jahn, Ullrich,Ma?ek, Tomá?
, p. 11608 - 11632 (2021/09/02)
The Baeyer-Villiger or Beckmann rearrangements are established methods for the cleavage of ketone derivatives under acidic conditions, proceeding for unsymmetrical precursors selectively at the more substituted site. However, the fragmentation regioselectivity cannot be switched and fragmentation at the less-substituted terminus is so far not possible. We report here that the reaction of ketone enolates with commercial alkyl nitrites provides a direct and regioselective way of fragmenting ketones into esters and oximes or ω-hydroxyimino esters, respectively. A comprehensive study of the scope of this reaction with respect to ketone classes and alkyl nitrites is presented. Control over the site of cleavage is gained through regioselective enolate formation by various bases. Oxidation of kinetic enolates of unsymmetrical ketones leads to the otherwise unavailable "anti-Beckmann"cleavage at the less-substituted side chain, while cleavage of thermodynamic enolates of the same ketones represents an alternative to the Baeyer-Villiger oxidation or the Beckmann rearrangement under basic conditions. The method is suited for the transformation of natural products and enables access to orthogonally reactive dicarbonyl compounds.
Ribavirin semi-antigen and artificial antigen and its preparation method and application (by machine translation)
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Paragraph 0047-0049; 0051, (2019/04/02)
The invention relates to ribavirin semi-antigen and artificial antigen and its preparation method and application. The ribavirin semi-antigen having a structure of formula (I) or formula (II) as shown: The ribavirin artificial antigen is represented by t
A fluorobenzene imidazole impurity E preparation method
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Paragraph 0060; 0063; 0064, (2019/04/10)
The invention discloses a fluorobenzene imidazole impurity E preparation method. Characterized in that in order to para-benzoic acid as the starting material, after chlorination reaction, esterification reaction, a Friedel-crafts acylation reaction, hydro