Trifluoroacetic acid → (2S-trans)-3-Amino-2-methyl-4-oxo-1-azetidinephosphonic acid, 2-(1,4-dihydro-5-hydroxy-4-oxo-2-pyridinyl)-2-oxoethyl ester, trifluoroacetate salt

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Reaction Steps

Trifluoroacetic acid (3 ml) was added to a 5° C. stirred suspension of (2S-trans)-[1-[[2-(1,4-dihydro-5-hydroxy-4-oxo-2-pyridinyl)-2-oxoethoxy]hydroxyphosphinyl]-2-methyl-4-oxo-3-azetidinyl]carbamic acid, 1,1-dimethylethyl ester, monopotassium salt (375 mg) in 4 ml of dry dichloromethane containing 1 ml of anisole. After about three minutes, the solid dissolved and the mixture was stirred for 1.25 hours at 5° C. TLC indicated the reaction was essentially complete. Toluene (2 ml) was added and the mixture was concentrated in vacuo to a viscous brown oil. The oil was washed twice with hexane, then triturated with ether. The resultant solid was washed twice with ether and dried in vacuo to afford 0.437 g of crude title compound, which was used directly in the next step.

Provenance & Evidence