p-Toluenesulfonic acid monohydrate → p-Toluenesulfonic acid dihydrate

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Reaction Steps

To an ice-cooled solution of potassium 6-[N-(1-methoxycarbonylpropen-2-yl)-D-α-amino-α-phenylacetamido]penicillanate (415.5 g) in dimethyl formamide (750 ml), iodomethyl penicillanate 1,1-dioxide (279.1 g) was added with stirring. After stirring for 40 minutes at approximately 5° C., ethyl acetate (2 liter) was added and the resulting solution washed with water (400 ml), followed by saturated aqueous sodium chloride (400 ml). The washings were extracted with ethyl acetate (2×400 ml), whereupon the ethyl acetate phases were combined and washed with saturated aqueous sodium chloride (2×400 ml) to give a solution containing the amino-protected VD 1827. This was hydrolyzed at an apparent pH-value of 2.5-3 (glass calomel electrode) by addition of a solution of 4-toluenesulfonic acid monohydrate (142.5 g) in ethyl acetate (1 liter). After stirring for 1 hour at 5° C., the crystals were filtered off, washed with ethyl acetate and dried to give 550.9 g of the crude title compound.

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