109715-77-7Relevant academic research and scientific papers
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 (1991)
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.
Method for manufacturing stereoselective preparation of 4-BMA using a chiral auxiliary and chiral auxiliary
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Page/Page column 2, (2011/06/26)
The present invention relates to a process for preparing (3R,4S)-3-[[[R]-1′-t-butyldimethylsilyloxy]ethyl]-4-[(R)-1″-carboxyethyl]-2-azetidinone (beta-methylazetidin-2-one; 4-BMA), a key intermediate for the synthesis of carbapenem and penem antibiotics. Specifically, the present invention relates to a process comprising first, the preparation of a chiral auxiliary from cheap L-Phenylalaninol, and then the preparation of 4-BMA in high yield and high selectivity, under industrially mild condition.
Method for manufacturing stereoselective preparation of 4-bma using a chiral auxiliary and chiral auxiliary
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Page/Page column 4-5; 9, (2011/08/04)
The present invention relates to a process for preparing (3R,4S)-3-[[[R]-1 ' -t-butyldimethylsilyloxy ]ethyl]-4-[(R)-1 "-carboxyethyl]-2-azetidinone (beta- methylazetidin-2-one; 4-BMA), a key intermediate for the synthesis of carbapenem and penem antibiotics. Specifically, the present invention relates to a process comprising first, the preparation of a chiral auxiliary from cheap L-Phenylalaninol, and then the preparation of 4-BMA in high yield and high selectivity, under industrially mild condition.
Process for the preparation of 4-substituted azetidinone derivatives
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Page column 22, (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.
