- METHOD OF PREPARING INTERMEDIATES OF PENEM ANTIBIOTICS
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The present invention relates to a method of preparing bicyclic keto esters, which are intermediates for carbapenem-based antibiotics. The method of preparing carbapenem-based antibiotic intermediates according to the present invention has not only the fast reaction rate using co-catalysts and specific reaction solvents which may be allowed to have high activity of rhodium catalysts, but also reduces the amount of expensive rhodium catalysts. Therefore, the present invention is very economical and useful, in industrial aspects.
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Page/Page column 28; 30
(2009/06/27)
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- Stereoselective reactions. XX. Synthetic studies on optically active β-lactams. III. Stereocontrolled synthesis of chiral intermediate to (+)-thienamycin from D-glucose
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A chiral key intermediate (19a) for the synthesis of (+)-thienamycin was synthesized starting from D-glucose. The enol ether 13, obtained from the ketone 11 by Horner-Wittig reaction, was transformed to the corresponding methyl ester 16 by pyridinium chlorochromate oxidation or by employing the Wacker process. The ester 16 was further converted to the β-lactam 19a, which is a useful chiral precursor to (+)-thienamycin.
- Ikota,Yoshino,Koga
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p. 2201 - 2206
(2007/10/02)
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- Simple and Condensed β-Lactams. Part 9. Elaboration of the 3-(1-Hydroxyethyl) Side Chains of Potential Intermediates of Carbapenem Antibiotics via the 2-Methyl-1,3-dioxolan-2-yl Group
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Deketalization of the trans compounds methyl and ethyl (2RS,3RS)-1-(2,4-dimethoxybenzyl)-3-(2-methyl-1,3-dioxolan-2-yl)-4-oxoazetidine-2-carboxylates 5b and 5c, and of the cis isomer (6b) of the latter leads to 85:15 mixtures of the trans- and cis-compounds methyl (2RS,3RS)- and (2RS,3SR)-3-acetyl-1-(2,4-dimethoxybenzyl)-4-oxoazetidine-2-carboxylate (7a) and (8a), respectively of the corresponding ethyl esters (7b) and (8b).Sodium borohydride reduction of the mixture of the trans- and cis-esters (7b) and (8b) gives a mixture of the 1'-epimeric trans-compounds ethyl(2RS,3RS)-1-(2,4-dimethoxybenzyl)-3--4-oxazetidine-2-carboxylate (9b) and (10b).Similar mixtures of 1'-epimeric compounds of the types (9) and (10), carrying a variety of substituents attached to position 2 of their azetidine rings were obtained by successive deketalization and reduction of the corresponding trans-(5) and cis-(6) compounds or their mixtures, as well as by other methods.Ring closure of a mixture of the pair of the 1'-epimeric trans-compounds p-nitrobenzyl 2-diazo-4--4-oxo-azetidin-2-yl>-3-oxobutanoates (9n) and (10n) gave a mixture of the 1'-epimeric compounds p-nitrobenzyl 6--2,7-dioxo-(3RS,5RS,6SR)-carbapenam-3-carboxylates (11) and (12) which was converted into a mixture (13) of the 1'-epimeric bis-protected thienamycin analogues p-nitrobenzyl 2-(2-formylaminoethylthio)-6--7-oxo-(5RS,6SR)-carbapen-2-em-3-carboxylates.
- Fetter, Jozsef,Lempert, Karoly,Kajtar-Peredy, Maria,Simig, Gyula
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p. 1135 - 1142
(2007/10/02)
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- FROM PENICILLIN TO PENEM AND CARBAPENEM. SYNTHESIS OF 2-OXOCARBAPENAM DERIVATIVE
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Previously obtained 4-iodomethylazetidinone derivative (2a) is transformed via the trans-iodopropenylation method into the β-keto ester (8), which is thought to be an important precursor for the synthesis of the carbapenem derivatives.
- Hirai, Koichi,Iwano, Yuji,Fujimoto, Katsumi
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p. 3251 - 3254
(2007/10/02)
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- A PRACTICAL SYNTHESIS OF (+/-)-THIENAMYCIN
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An efficient and operationally simply synthesis of (+/-)-thienamycin is described.
- Melillo, D.G.,Shinkai, I.,Liu, T.,Ryan, K.,Sletzinger, M.
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p. 2783 - 2786
(2007/10/02)
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