- Preparation method D - (-) - formyl mandelic acid chloride
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D - Mandelic acid is used. Dichloromethane is reacted with little excess of anhydrous formic acid under the catalysis of activated carbon, and a formylation reaction takes place with solid light as a dehydrating agent to obtain a colorless viscous D (-) formyl mandelic acid which is used directly in the next step without purification. The colorless viscous material D (-) formyl mandelic acid is added with dichloromethane, the activated carbon catalyst is added, the light solution is added dropwise, the heat insulation reaction is finished, and the methylene chloride is distilled and recovered, and the colorless and transparent liquid is D (-) formyl mandelic acid chloride. The reaction is mild and environment-friendly, the reaction conversion rate and the product purity can be effectively improved, the production cost is effectively reduced, the operation is simple and convenient, and the industrial production is facilitated.
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Paragraph 0038-0041
(2021/09/08)
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- Methylene penam and derivatives thereof
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There are presented compounds of the formula STR1 wherein R2, R3, R4 and m are as described herein.
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- Spirocyclic Side-chain Derivatives of Penicillin and Cephalosporin
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A series of two spirocyclic oxazolidinone derivatives of penicillin and four derivatives of cephalosporin have been prepared, as well as a benzoxazine conjugate of cephalosporin, with the object of freezing the conformation of the 6(7)-amide side-chain bearing a pendant aromatic ring.The antibacterial properties of these derivatives are discussed.
- Sammes, Peter G.,Smith, Steven,Ross, Barry C.
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p. 2117 - 2124
(2007/10/02)
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