7- -3-methyl-3-cephem4-carboxylic acid

To a solution of 7 (d-p-hydroxyphenyl-0i-carboxyacetamido-7(l-methoxy-3-(1-methyl-tetrazol-5-vl)thiomethyl-1-oxadethia-3-cephem4-carboxylic acid (359 mg) in methanol (7 ml) is added a solution of sodium 2-ethylhexanoate in methanol (2 mols/liter 1.73 ml) at room temperature. After stirring for 10 minutes, the reaction mixture is diluted with ethyl acetate, stirred for 5 minutes, and filtered to collect separated solid, which is washed with ethyl acetate, and dried to give disodium salt of 7 (a-p-hydroxyphenyl-a-carboxyacetamido)-7Q -methoxy-3-(1-methyl-tetrazol-5-vl)thiomethyl-1-oxadethia-3-cephem4-carboxylic acid (342 mg). Yield 885%. Colorless powder. MP decomposition from 170°C. 

To 13 of ethyl acetate were added 85.1 g (2.59 mols) of 7-amino-3-(1 -methyl-1 H-tetrazol-5-ylthiomethyl)-3-cephem4-carboxylic acid and 1,361 g (10.37 mols) of monotrimethylsilyl acetamide, and the mixture was stirred at 50°C until a clear solution was obtained. The solution was cooled to 20°C and 514 g (2.59 mols) of 0-formyl mandeloyl chloride was added at a rate such that the temperature of the reaction solution was maintained between about 20°C to 25°Cwith ice-cooling. 

The reaction mixture was stirred for 1.5 hours at about room temperature after the addition of the mandeloyl chloride was completed. Five liters of water were then added to the reaction mixture and the diluted mixture was stirred for about 10 minutes. The organic layer was separated and was washed twice with water. The combined washes are extracted with 1,5 of ethyl acetate and the extract Is combined with the washed organic layer. The whole was dried over magnesium sulfate, filtered and evaporated in vacuo on a 25°C water bath to yield 1,460 g of product,7-(D-2-formyloxy-2-phenylacetamido)-3-(1-methyl-1H-tetrazol-5-ylthlomethyl)-3-cephem4-carboxylic acid, as a yellow foam. 

Chemical Name 7-(D-a-Amino-a-(p-hydroxyphenyl)acetamido] -3-(19,3-triazol-5-ylthio-methyl)-3-cephem4-carboxylic acid... 

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