86978-24-7Relevant articles and documents
Method for preparing cefcapene side chain acid
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Paragraph 0040; 0041, (2017/07/20)
The invention relates to a method for preparing cefcapene side chain acid, and belongs to the technical field of refined medical intermediates. The method comprises the following steps: adding ketene dimer into an alcohol organic solvent in the presence of nitrogen, dropwise adding bromine for reaction, adding a mixed liquid of dichloromethane and water for quenching reaction, separating an organic phase, adding acetic acid into the organic phase, dropwise adding propyl aldehyde and an organic alkali catalyst A for reaction, then adding thiourea for reaction, performing vacuum distillation for concentration, adding dichloromethane, di-tert-butyl dicarbonate ester and an organic alkali catalyst B into a concentrated solution for reaction, adding a caustic soda liquid for reaction, cooling, dropwise adding hydrochloric acid for crystallization, filtering, performing drip washing with an isopropanol solution, and drying, thereby obtaining (Z)-2-(2-t-butyloxycarboryl aminothiazole-4-yl)-2-pentenoic acid, that is, the cefcapene side chain acid. As the ketene dimer is adopted as an initial raw material, the method is small in side reaction, high in yield, high in purity of obtained products and gentle in reaction condition, and industrial production can be relatively easily achieved.
Stereoselective or exclusive synthesis of ethyl (Z)-2-(2-substituted- thiazol-4-yl)pent-2-enoates from ethyl (E/Z)-2-(2-bromoacetyl)pent-2-enoate
Zhai, Jiao-Jiao,Jiang, Jian-An,Zhang, Shun-Li,Chen, Cheng,Liu, Hong-Wei,Liao, Dao-Hua,Ji, Ya-Fei
, p. 1399 - 1404 (2013/07/26)
A stereoselective or exclusive approach to a series of ethyl (Z)-2-(2-substituted-thiazol-4-yl)pent-2-enoates from ethyl (E/Z)-2-(2- bromoacetyl)pent-2-enoate and thioureas or thioamides was reported in good yields. This approach involves a quaternary carbon stereocontrolled cis-configuration formation, and opportunely blocking a potential E/Z isomerization. The practical applicability was highlighted by the synthesis of (Z)-2-(2-tert-butoxycarbonylaminothiazol-4-yl)pent-2-enoic acid, a commercially important side-chain material of cefcapene pivoxil, in a two-step procedure. Georg Thieme Verlag Stuttgart · New York.