Sodium Chloride → 6-Amino-2,2-dimethyl-3-(2-[pivaloyloxymethyl]tetrazol-5-yl)penam hydrochloride

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Reaction Conditions

Reaction Steps

To a stirred solution of 0.932 g. (7.21 m mole) of quinoline in 8.0 ml. of chloroform is added 0.840 g. (4.05 m mole) of phosphorus pentachloride. The suspension is cooled to -15° C., and then 1.81 g. (3.84 m mole) of 6-(2-phenylacetamido)-2,2-dimethyl-3-(2-[pivaloyloxymethyl]tetrazol-5-yl)penam is added. Stirring is continued for a further 30 minutes, at ca. -5° C., and then 2.15 g. (35.7 m mole) of n-propanol is added. Stirring is continued for a further 30 minutes, again at ca. -5° C., and then 25 ml. of 90:10 isopropyl ether-acetone is added, followed immediately by a solution of 1.35 g. of sodium chloride in 6.02 ml. of water. The temperature rises to 15° C. and then it is lowered again to -15° C. The precipitate which has formed is filtered off and dried, giving 1.33 g. (88% yield) of 6-amino-2,2-dimethyl-3-(2-[pivaloyloxymethyl]tetrazol-5-yl)penam hydrochloride. The infrared spectrum (KBr disc) shows absorptions at 1785 cm-1 (β-lactam) and 1750 cm-1 (ester). The NMR spectrum (DMSO-d6) shows absorptions at 6.70 ppm (singlet, 2H, pivaloyloxy methylene hydrogens), 5.75 ppm (doublet, 1H, C-5 hydrogen), 5.50 ppm (singlet, 1H, C-3 hydrogen), 5.70 ppm (doublet, 1H, C-6 hydrogen), 1.75 ppm (singlet, 3H, C-2 methyl hydrogens), 1.20 ppm (singlet, 9H, t-butyl hydrogens) and 1.10 ppm (singlet, 3H, C-2 methyl hydrogens).

Provenance & Evidence