220504-75-6Relevant articles and documents
Synthesis method of 2, 4-dimethyl-3-methylsulfonylbenzoic acid
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Paragraph 0028-0036, (2020/06/16)
The invention discloses a synthesis method of 2, 4-dimethyl-3-methylsulfonylbenzoic acid. The method comprises the following steps of: nitrifying 2, 4-dimethylbenzoic acid serving as a raw material byusing concentrated nitric acid, carrying out NIS iodination, iron powder acetic acid reduction, hypophosphorous acid and sodium nitrite system deamination, carrying out methylthiolation by using dimethyl disulfide, oxidizing by using peracetic acid, extracting the reaction solution by using dichloromethane after the reaction is finished, drying, and carrying out spin-drying to obtain the target product 2, 4-dimethyl-3-methylsulfonylbenzoic acid. The method has the advantages of easily available raw materials, feasible route, simple operation, high product purity and low cost.
Synthesis and reactivity with β-lactamases of 'penicillin-like' cyclic depsipeptides
Cabaret,Adediran,Garcia Gonzalez,Pratt,Wakselman
, p. 713 - 720 (2007/10/03)
Several 7-carboxy-3-amido-3,4-dihydro-2H-1-benzopyran-2-ones have been synthesized as potential β-lactamase substrates and/or mechanism-based inhibitors. Substituted o-tyrosine precursors were prepared by the Sorensen method and then heated in vacuo to give the lactones. These compounds are cyclic analogues of aryl phenaceturates which are known to be β-lactamase substrates. The goal of incorporating the scissile ester group into a lactone was to retain the leaving group tethered to the acyl moiety at the acyl- enzyme stage of turnover by serine β-lactamases, in a manner similar to that during penicillin turnover. Further, in two cases, a functionalized methylene group para to the leaving group phenoxide oxygen was incorporated. These molecules possess a latent p-quinone methide electrophile which could, in principle, be unmasked during enzymic turnover and react with an active site nucleophile. All of these compounds were found to be substrates of class A and C β-lactamases, the first δ-lactones with such activity. Generally, k(cat) values were smaller than for the analogous acyclic depsipeptides, which suggests that the tethered leaving group may obstruct the attack of water on the acyl-enzymes. Further exploration of this structural theme might lead to quite inert acyl-enzymes and thus to significant inhibitors. Despite the apparent advantage offered by the longer-lived acyl-enzymes, the functionalized compounds were no better as irreversible inhibitors than comparable acyclic compounds [Cabaret, D.; Liu, J.; Wakselman, M.; Pratt, R. F.; Xu, Y. Bioorg. Med. Chem. 1994, 2, 757-771]. Thus, even tethered quinone methides, at least when placed as dictated by the structures of the present compounds, were unable to efficiently trap a nucleophile at serine β- lactamase active sites.
