Perchloric Acid → HCID 15593985, compound

Participants

Reaction Steps

18 g. of 7-amino-3-[[(5-methyl-1,3,4-thiadiazol-5-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid are suspended in 350 ml. of tetrahydrofuran. 4.1 ml. of 70% perchloric acid are added dropwise. After 30 minutes, a slightly turbid solution forms. This solution is filtered and to the filtrate is added dropwise with stirring 12 g. of diphenyldiazomethane and 20 ml. of tetrahydrofuran. After three hours, the reaction mixture is poured into 2 liters of absolute ether. The solid, light brown precipitate, which is the perchloric acid salt of the desired product, is dried over Kieselgel in a desiccator. To obtain the base, the perchloric acid salt is dissolved in water and treated with the calculated equivalent of potassium bicarbonate. The aqueous solution obtained is extracted with chloroform. The chloroform phase is treated with activated carbon and sodium sulfate to obtain the 10 g. of the product, 7-amino-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2 -ene-2-carboxylic acid, diphenylmethyl ester, as a light brown powder, m.p. 157°-159°. The product is recrystallized from tetrahydrofuran/petroleum ether. The isomeric thiadiazolyl derivative is similarly obtained from the product of Example 20.

Provenance & Evidence