114341-89-8Relevant articles and documents
Process for the preparation of 4-substituted azetidinone derivatives
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Page column 21, (2008/06/13)
Disclosed is a process for the preparation of a 4-substituted azetidinone derivative, which comprises reacting an azetidinone derivative and an amide compound in the presence of a magnesium compound such as those represented by the following formulas (II): and (IV): represented by the following formula (III): MgR5R6??(III) wherein R5represents a C1-12alkyl group, a C2-5alkenyl group, a 5- to 8-membered alicyclic group which may be substituted by a lower C1-4alkyl group, a phenyl group which may be substituted by a lower C1-4alkyl group, a lower C1-4alkoxy group or a halogen atom or a benzyl group which may be substituted by a lower C1-4alkyl group, a lower C1-4alkoxy group or a halogen atom, and R6represents a halogen atom, a methanesulfonyloxy group, a benzenesulfonyloxy group, a p-toluenesulfonyloxy group, a trifluoromethanesulfonyloxy group, an acetoxy group which may be substituted by a halogen atom or a cyano group or an OR7group (R7representing a lower C1-4alkyl group, a substituted or unsubstituted phenyl group or a substituted or unsubstituted benzyl group). The process provides an industrially excellent process for the preparation of a 4-substituted azetidinone derivative which permits the selective preparation of an intermediate for the synthesis of a carbapenem antibacterial agent having a desired 1-β′ configuration.
A highly stereoselective synthesis of the 1β-methylcarbapenem key intermediate from (R)-3-hydroxybutyric acid
Kobayashi, Yuko,Ito, Yoshio,Terashima, Shiro
, p. 55 - 66 (2007/10/02)
(3R,4R)-4-Acetoxy-3-[(R)-1-(formyloxy)ethyl]-2-azetidinone 6 could be prepared highly stereoselectivity from (R)-3-hydroxybutyric acid by employing the [2+2]-cycloaddition reaction of chlorosulfonyl isocyanate with the 2H,4H-1,3-dioxin derivative and the Baeyer-Villiger reaction accompanying novel cleavage of the acetal moiety. The Reformatsky reaction of 6 with sterically crowded 3-(2-bromopropionyl)-2-oxazolidone derivatives readily afforded the title key intermediate after sequential chemical manipulations.
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
Ito,Sasaki,Tamoto,Sunagawa,Terashima
, p. 2801 - 2820 (2007/10/02)
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.
A NOVEL SYNTHESIS OF THE 1β-METHYLCARBAPENEM KEY INTERMEDIATE EMPLOYING THE -CYCLOADDITION REACTION OF CHLOROSULFONYL ISOCYANATE WITH A 4H-1,3-DIOXIN DERIVATIVE
Ito, Yoshio,Kobayashi, Yuko,Terashima, Shiro
, p. 5631 - 5634 (2007/10/02)
A highly stereoselective synthetic route to the title compound was explored by featuring the -cycloaddition reaction of chlorosulfonyl isocyanate with the 4H-1,3-dioxin derivative readily obtainable from methyl (R)-3-hydroxybutyrate, the Baeyer-Villinger reaction resulting in novel cleavage of the acetal moiety, and the Reformatsky reaction with sterically crowded 3-(2-bromopropionyl)-2-oxazolidone derivatives.
