of 764 mcg mg vs hetacillin c 21 h 28 n 3 o 5 hcl calculated c 53 65 h 6 00 n 8 94 cl 7 54 found c 53 44 h 5 95 n 8 74 cl 7 72 three millimoles 1 3 grams of p toluenesulfonate salt of methoxymethyl 6 aminopenicillanate was admixed with 40 ml of acetone and 10 ml of water the mixture was cooled to between 0 u00b0 c and 5 u00b0 c to the cooled mixture there was added six millimoles 1 2 grams of phenylglycyl chloride hydrochloride with vigorous stirring the ph of the reaction mixture was maintained between 2 0 and 2 8 by addition of 10 sodium hydroxide as needed after the reaction was complete the ph was adjusted to between 6 5 and 7 0 and the mixture was filtered and diluted to 200 ml with acetone to give a solution of the methoxymethyl ester of ampicillin at 25 u00b0 c in 150 ml of dimethylacetamide there was dissolved 37 1 grams 0 1 mole of sodium ampicillin the solution was cooled to 0 u00b0 c to 5 u00b0 c and 8 0 ml 0 1 mole of chloromethylmethyl ether added after one hour of stirring thin layer chromotography showed no sodium ampicillin remaining the mixture was.