tert-Butyl methyl ether → Sulopenem Etzadroxil

Participants

Reaction Steps

The semi-crude tert-butyl methyl ether solution of 2-ethyl butyric acid iodomethyl ester from Step 3 was added to a slurry of sulopenem (750 g) in acetone (5.9 L). N,N-Diisopropylethylamine (DIEA) (319 g) in acetone (0.5 L) was added and the mixture was stirred at ambient temperature until reaction completion. Low pyrogen water (6.5 L) and heptane (3.75 L) were added and the phases were separated. The aqueous layer was extracted first with heptane (5 L) and then with ethyl acetate (2×6 L). The ethyl acetate extracts were combined and washed with 5% aqueous sodium thiosulfate (6 L), low pyrogen water (6 L) and 10% aqueous sodium chloride (6 L). The organic extract was treated with activated carbon (75 g) and magnesium sulfate (150 g), then was filtered. The filter cake was washed with ethyl acetate (2×1 L) and the filtrate was evaporated to dryness to provide the crude product (0.8 kg). Ethyl acetate (2.4 L) was added and the solution was heated (45° C.) to achieve dissolution. This solution was then hot-filtered and tert-butyl methyl ether (4.7 L) was added. The resulting slurry was granulated for 10 minutes at 40° C. to 50° C. and was then cooled slowly to less than 10° C. The resulting solid was collected, washed with a 1:2 mixture of ethyl acetate and tert-butyl methyl ether (4×0.5 L) and dried to constant weight under vacuum at up to 50° C. to give 0.57 kg of the desired product (60% yield).

Provenance & Evidence