p-Toluenesulfonic acid monohydrate → p-Toluenesulfonic acid

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Reaction Steps

A mixture of p-toluenesulphonic acid monohydrate (1.34 g) and benzhydryl 6-(2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopent-1-yl)penicillanate 1α-oxide (3.60 g) in ethyl acetate (25 ml) was stirred for 1.5 hours at room temperature. The solvent was evaporated under reduced pressure and the residue crystallised from diethyl ether to give yellow crystals of the p-toluenesulphonic acid salt of benzyhydryl 6-aminopenicillanate 1α-oxide (2.03 g). A solution of this tosylate in methylene chloride (25 ml) was washed twice with saturated aqueous sodium bicarbonate (25 ml) and then brine (25 ml), and then stirred rapidly for 3 hours at room temperature with phenoxyacetyl chloride (0.46 ml) and saturated aqueous sodium bicarbonate (25 ml). The organic layer was separated, washed with saturated aqueous sodium bicarbonate, dried with magnesium sulphate, and evaporated under reduced pressure to give the title compound as a foam, nmr (CDCl3) δ 1.03 (s, 3H), 1.60 (s, 3H), 4.46 (s, 1H), 4.64 (d, J=4 Hz, 1H), 5.42 (dd, J=4 and 8 Hz, 1H), 6.78 (d, J=4 Hz, 1H), 6.84 (s, 1H), 7.16 (s, 10H).

Provenance & Evidence