104527-11-9Relevant academic research and scientific papers
AN IMPROVED ENTRY TO A KEY INTERMEDIATE FOR THIENAMYCIN SYNTHESIS FROM METHYL (R)-3-HYDROXYBUTANOATE VIA DIRECT EPIMERIZATION AT C-3 ON 2-AZETIDINONE RINGS
Chiba, Toshiyuki,Nakai, Takeshi
, p. 4647 - 4648 (1985)
An improved entry to a key thienamycin intermediate is described which relies upon the direct epimerization at C-3 of the 3-(1-hydroxyethyl)-2-azetidinone derivatives readily obtained from methyl (R)-3-hydroxybutanoate.
A SYNTHETIC APPROACH TO (+)-THIENAMYCIN FROM METHYL (R)-3-HYDROXYBUTANOATE. A NEW ENTRY TO (3R, 4R)-3--4-ACETOXY-2-AZETIDINONE
Chiba, Toshiyuki,Nakai, Takeshi
, p. 651 - 654 (1985)
A new entry to the O-silylated form of the title azetidinone, a well-established key intermediate for thienamycin synthesis, is described which relies on the stereocontrolled transformation of the 2-azetidinone obtained via the condensation of methyl (R)-3-hydroxybutanoate with the N-silylimine of trimethylsilylpropynal.
Copper-assisted substitution reaction for phenylthio group of a 4- phenylthioazetidinone derivative
Shimamoto,Inoue,Yoshida,Tanaka,Nakatsuka,Ishiguro
, p. 5887 - 5888 (1994)
The phenylthio group of 4-phenylthioazetidinone (1) was readily substituted with copper(I) salts of carboxylates, thiocarboxylates, and copper(I) enolates of malonates and β-ketoesters to give synthetic intermediates (3 and 4) for penem and carbapenem antibiotics.
Novel synthesis of (3R,4R)-4-acetoxy-3-[1′(R)-tert- butyldimethylsilyloxyethyl] azetidin-2-one: A key intermediate for penem and carbapenem synthesis
Singh, Santosh Kumar,Singh,Byri,Satish,Dhamjewar, Ravi,Gopalan
, p. 456 - 464 (2008)
Diastereoselective synthesis of (3R,4R)-4-acetoxy-3-[1′(R)-tert- butyldimethylsilyloxyethyl] azetidin-2-one (AOSA) using (-)-D-2,10-camphorsultam as a key and recyclable chiral auxiliary is described. Copyright Taylor & Francis Group, LLC.
A practical synthesis of a key intermediate for the production of β- lactam antibiotics
Cainelli, Gianfranco,Galletti, Paola,Giacomini, Daria
, p. 7779 - 7782 (1998)
N-(p-methoxyphenyl)-hexahydro-1,3,5-triazine in presence of a Lewis acid and (R)-3-(t-butyldimethylsilyloxy)butyric acid chloride with Et3N directly furnish (3S,1'R)-N-p-methoxyphenyl-3-(l-t- butyldimethylsilyloxy)ethylazetidin-2-one with good diastereoselectivity. This product is transformed into the 4-acetoxy-azetidinone 1, a key intermediate in the synthesis of β-lactam antibiotics.
Novel stereoselective synthesis of 4-acetoxyazetidinone from methyl 6,6-dibromopenicillanate: Key intermediate for the preparation of carbapenem antibiotics
Long, Bohua,Xiang, Jiannan
, p. 4019 - 4029 (2009)
A novel and practical process for the completely stereoselective synthesis of carbapenem key intermediate (3R,4R)-4-acetoxy-3-[(R)-1-((t- butyldimethylsilyl)oxy)ethyl]-2-azetidinone has been developed by starting from methyl 6,6-dibromopenicillanate. Aldol condensation of the magnesium enolate derived from the-sulfoxide with acetaldehyde allows for the stereospecific introduction of a 1-R-hydroxyethyl substituent as C-6. The hydroxyethylated product was reduced with Zn-NH4OAc in tetrahydrofuran (THF) efficiently to give methyl 6-(1-hydroxyethyl)-penicillanate-1-oxide. Protection of the hydroxy group followed by treatment with 2-mercaptobenzothiazole afforded the dithioazetidinone, which was easily reduced and methylated to give 4-methylthioazetidinone. Then this compound was oxidized with permanganate to selectively remove the side chain at the N-position to afford the 4-methylthioazetidinone derivative. A facile conversion of the methylthio group to acetoxy for a practical synthesis of 4-acetoxyazetidinone was also reported. This method provided an efficient and cost-effective process with good overall yield and excellent stereoselectivity.
Method for removing P-methoxyphenyl protecting group on amide group
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Paragraph 0031-0057, (2021/10/27)
The invention provides a method for removing p-methoxyphenyl protecting groups on amide groups. The method comprises the steps of sequentially performing ozonation reaction and quenching treatment on a substrate and ozone in the presence of an organic solvent to obtain an oxidation intermediate, wherein an amide group in the substrate is protected by a p-methoxyphenyl group. The oxidation intermediate is subjected to a reduction reaction with carbon monoxide or a mixed gas containing carbon monoxide to remove p-methoxyphenyl. After the substrate and the ozone are subjected to ozonation reaction, the product system of the ozonation reaction is quenched, and then the quenched oxidized intermediate and carbon monoxide are subjected to a reduction reaction to remove p-methoxyphenyl groups to obtain the required amide organic matters. To the method for removing the P-methoxyphenyl protecting group on the amide group, thiourea is not needed, so that the whole process does not generate sulfur-containing wastewater, the cost is lower, and the method is more environmentally friendly.
Preparation method of azetidinone compound and preparation method 4 - acyloxy-azetidinone compound
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Paragraph 0101; 0103; 0104, (2021/11/19)
The invention provides a preparation method of a azetidinone compound and a preparation method of 4 - acyloxy-azetidinone compound. The preparation method comprises the following steps S1, an epoxy amide compound reacts with I alkali reagents to form a ring reaction, and first 1st reaction systems are obtained. Step S2: The first reaction system is subjected to hydroxyl protection reaction with a raw material including a silanization reagent and a nitrogen-containing basic organic matter to obtain second reaction systems. In step S3, second reaction system and second base reagent are subjected to isomerization reaction to obtain the azetidinone compound, wherein the epoxy amide compound has the structure shown VI, the separation process of the isomer product of the structure shown II and formula III IV is avoided, and the selectivity and yield of the azetidinone compound are improved.
Preparation method of 4AA
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Paragraph 0016; 0018; 0020-0021; 0023-0024; 0026, (2021/07/28)
The invention discloses a preparation method of 4AA. The preparation method comprises the following steps: S1, preparing a first intermediate from benzamide and a formaldehyde aqueous solution; S2, preparing a second intermediate from the first intermediate, thionyl chloride, toluene and n-heptane; S3, preparing a third intermediate from the second intermediate, methyl acetoacetate, sodium methoxide, toluene, diluted hydrochloric acid and isopropanol; S4, preparing a fourth intermediate from the third intermediate, reductase, ethyl acetate, saturated sodium bicarbonate and saturated salt water; S5, preparing a fifth intermediate from the fourth intermediate, imidazole, TBSCL and methylbenzene; S6, preparing a sixth intermediate from the fifth intermediate, ethanolamine, methanol and n-heptane; S7, preparing a seventh intermediate by using the sixth intermediate, a Grignard reagent and n-heptane; and S8, preparing 4AA from the seventh intermediate, ruthenium trichloride, potassium acetate, ethyl acetate, acetic acid and a peracetic acid solution.
Preparation method of penem antibiotic intermediate 4 - acetoxy azacyclobutanone (by machine translation)
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Paragraph 0033; 0036-0039; 0040; 0043-0046; 0054-0060, (2020/09/30)
The invention discloses a preparation method of penem antibiotic intermediate 4 - acetoxy azacyclobutanone (4 - AA), and specifically discloses a preparation method of 4 - acetoxyazacyclobutanone (4 - AA) in an organic solvent under the action of a metal catalyst and an oxidant, and has the characteristics of being economical and efficient, small in environmental pollution and high in yield 4 - 4 - AA. (by machine translation)
