| 摘要 |
<p>A 3-substituted 7-aminocephalosporanic acid of formula: <IMAGE> where R1 is hydrogen, methyl of methoxy, Y is nitrogen, oxygen sulphur or a sulphoxide group, R2 is a group selected from among azide or from a radical having the formula R3-S- where R3 may be, among others, alkyl, aliphatic acyl, methyl and chlorine or methoxy substituted aromatic acyl, is prepared. A compound of formula <IMAGE> (X being chlorine, carbamoyloxy or acetoxy) is added to a medium constituted by water, a compound which may be nitric acid or a compound of formula R3-SH and a tertiary organic base. With a reaction isoelectric pH regulator, the mixture takes on a specific process pH analytical profile, the compounds of said mixture being reacted together at particular temperatures and with a specific process time.</p> |
