| abstract |
(6R,7R)-7-amino-3-(1-pyridiniummethyl)ceph-3-em-4-carboxylate dihydrochloride and its solvates are prepared in substantially pure form and can be acylated by conventional methods to yield a wide variety of cephalosporin antibiotics. The dihydrochloride is advantageously prepared in the form of its crystalline dihydrate. Processes for the preparation of the dihydrochloride and its solvates are described. The dihydrochloride and its solvates are particularly useful in the preparation of (6R,7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)ace tamido]-3-(1-pyridiniummethyl)ceph-3-em-4-carboxylate, in the course of the preparation of which the novel N,N-dimethylformamide solvate of (6R,7R)-7-[(Z)-2-(2-tritylaminothiazol-4-yl)-2-(2-t-butoxyprop-2-oxyim ino)acetamido[-3-(1-pyridiniummethyl)ceph-3-em-4-carboxylate may be isolated in substantially pure crystalline form. |