2-methylpropoxycarbonyl 2-[(2-methylpropan-2-yl)oxycarbonylamino]acetate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: One millimole of t-butoxycarbonyl-glycine in 10 ml methylene chloride at 0° is treated successively with one millimole each of triethylamine and isobutyl chloroformate, forming N-(t-butoxycarbonyl)glycyl i-butyl carbonate. To this solution at -78° is added p-nitrobenzyl 5-methoxymethyl 6H-1,3-thiazine-4-carboxylate and then a second millimole of triethylamine. The reaction mixture is allowed to warm to room temperature over one hour, and kept at 25° one hour. The mixture is then washed successively with aqueous pH 2 buffer, water, and aqueous bicarbonate, dried with MgSO4, filtered and evaporated, affording p-nitrobenzyl 7-t-butoxycarbonylamino-3-methoxymethyl decephalosporanate, which may be purified if desired by chromatography on silica gel, eluting with 4:1 chloroform-ethyl acetate.