Process for preparing alkoxylated derivatives of cephalosporin compounds

A process for preparing a compound having the formula ##STR13## wherein R.sup.11 is methyl, acetoxymethyl, (1-methyl-1H-tetrazol-5-yl) thiomethyl or 5-methyl-1,3,4-thiadiazol-2-yl-thiomethyl;

• R.sup.12 is tert-butoxycarbonyl, benzhydryloxycarbonyl, p-bromophenacyloxycarbonyl, p-methoxybenzyloxycarbonyl or 2,2,2-trichloroethyloxycarbonyl;
• and
• R is an alkoxy group having from 1 to 3 carbon atoms, which comprises contacting a compound having the formula ##STR14## wherein R.sup.11 and R.sup.12 are as defined above, with from about 1.1to about 4 equivalents of a halide cation-producing compound per equivalent of said compound of formula (IVa), in the presence of a lower alkanol having from 1 to 4 carbon atoms and from about 1.2 equivalents to about 2 equivalents of a base per equivalent of said compound of formula (IVa), at a temperature of from about 0.degree. C. to about -70.degree. C., said halide cation-producing compound being selected from the group consisting of a halogen, N-chlorosuccinimide, N-bromosuccinimide, N-chloroacetamide, N-chlorphthalimide, N-bromophthalimide, N-chlorbenzenesulfonamide, N-bromobenzenesulfonamide, N-chloro-p-toluenesulfonamide, N-bromo-p-toluenesulfonamide, 1-bromobenzotriazole, 1-chlorotriazine, N,N-dibromohydantoin, tert-butylhypochlorite and tert-butylhypoiodite, and said base being selected from the group consisting of an alkali metal hydroxide, an alkaline earth metal hydroxide, lithium methoxide, sodium methoxide, potassium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, calcium ethoxide, potassium tert-butoxide, lithium cyclopropoxide, lithium propargyloxide, lithium benzyloxide, sodium benzyloxide, lithium hydride, sodium hydride, calcium hydride, butyl lithium, phenyl lithium, trimethylamine, triethylamine, tributylamine, N-methylpiperidine, N,N'-dimethylpiperidine, N-methylpyrrolidine, 1,8-diazabicyclo-[5,4,0]-7-undecene, pyridine and picoline.