(Z)-2-(5-Amino-1,2,4-Thiadiazol-3-Yl)-2-Methoxy-Imino Acetic Acid
|School||Qingdao University of Science and Technology|
|Keywords||Antibiotic Cephalosporin Seven intermediates (Z)-2-(5)-methoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2-methoxyimioacetic acid|
(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid is a fourth-generation cephalosporin antibiotics two7side chains ofa important intermediate, using malononitrile, hydrogen chloride and methanol as the raw materials,(Z)-2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid was synthesized with the methods of substitution reaction, addition reaction, elimination reaction, closed loop, oxidation and recrystallization, etc. step.Focus on a single factor experiment method for each step of the synthesis reaction, the optimum reaction conditions were got initially.The results are shown as follows:The best conditions of synthesizing methyl cyanoacetimidate hydrochloride were that, solvent as Methyl tert-butyl ether.The reaction best materials than:n (malononitrile):n (methanol)=1:1; n (malononitrile):n (hydrogen chloride gas)=1:(1.0to1.1), stirring time of normal temperature as7h. The yield of product was97%.The best conditions of synthesizing3,3,3-trimethoxypropionitrile were that, reaction time as30℃, reaction time as32h, The yield of product was80%.The best conditions of synthesizing3,3-dimethoxyacrylonitrile were that, molecule of methanol removed by7-9minutes stirring under222～225℃. The yield of product was75%and the purity was98.99%.The best conditions of synthesizing3-Amino-5-methoxyisoxazole were that, the stirring time of45℃as3.5h and stirring time of60℃as4h.The yield of product was86.96%and the purity was98.98%.The best conditions of synthesizing methyl-2-(5methoxycarbonyl-amino-1,2,4-thiadiazol-3-yl) acetic acid were that, the stirring time of5℃as2.5h and stirring time of18℃as3h. Best washing times twice. The yield of product was65.65%.The best conditions of synthesizing(Z)-2-(5-methoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2-methoxy-ethyl imino were that, the reaction was carried out in the dark compartment under aerobic conditions, the reaction time is under the boiling condition11h,room temperature, the reaction time is5h.The best conditions of synthesizing (Z)-2-(5-methoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetic acid were that, the reaction time of5.5h at100℃, the ethyl acetate was extracted4times.The seven steps of process route cheap raw materials, reaction condition is mild, the operation is simple, high product purity and yield.