- A synthetic penem antibiotics of hand natural auxiliary base preparation method
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The present invention relates to the field of medicinal chemistry for the preparation of the product, in particular to a synthetic penem antibiotics of hand natural auxiliary base preparation method. The synthetic penem antibiotics of hand natural auxilia
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Paragraph 0014; 0015; 0016; 0017-0020
(2019/07/04)
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- 2-(2-substituted pyrrolidin-4-yl) thio-carbapenem derivatives
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The present invention relates to 2-(2-substituted pyrrolidin-4-yl)-thio-carbapenem derivatives and pharmaceutically acceptable salts thereof, to a process for preparing the derivatives, an intermediate compound for preparing the derivatives, an antibacterial composition containing the derivatives, and use of the derivatives as an antibacterial agent.
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- Heterocyclic compounds and their production
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A compound of the formula: STR1 wherein R1, R2, R3 and R4 are each a hydrogen atom, a lower alkyl group, an ar(lower)alkyl group or an aryl group, or R1 and R2 may be combined together to f
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- Highly stereocontrolled synthesis of the 1β-methylcarbapenem key intermediate by the Reformatsky reaction of 3-(2-bromopropionyl)-2-oxazolidone derivatives with a 4-acetoxy-2-azetidinone
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The key synthetic intermediate (4) of 1β-methylcarbapenems (1~3) was efficiently synthesized by employing highly stereocontrolled Reformatsky reaction (C4-alkylation) of 3-(2-bromopropionyl)-2-oxazolidone derivatives (6) with (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidino ne (5) in the presence of zinc dust followed by removal of 2-oxazolidone moieties. The best diastereoselectivity (β:α = 95:5) could be realized by uses of sterically crowded achiral 2-oxazolidone derivatives such as 4,4-dimethyl-, 4,4,5,5-tetramethyl, and 4,4-dibutyl-5,5-pentamethylene-2-oxazolidone and higher reaction temperatures (refluxing tetrahydrofran). The remarkable diastereoselectivities observed for the Reformatsky reactions could be explained by means of the weakly chelating transition state models.
- Ito,Sasaki,Tamoto,Sunagawa,Terashima
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p. 2801 - 2820
(2007/10/02)
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