Dimethyl Sulfoxide → HCID 86733038, compound

Participants

Reaction Steps

A solution of tirmethylsily 2,2-dimethyl-6β-trimethylsilylaminopenam-3α-carboxylate [prepared from the corresponding amino-acid (0.648 g.)] and propylene oxide (0.75 ml.) in dichloromethane (15 ml) was cooled to 0° and treated dropwise with a solution of 2-dichloroacetoxyimino(fur-2-yl)acetyl chloride [syn-isomer; prepared from the corresponding acid (0.579 g)] in dichloromethane (12 ml.). The resulting solution was maintained at 0° for 1 hour and was then evaporated to small volume and partitioned between ethylacetate and saturated sodium bicarbonate solution. The aqueous phase was washed with ethyl acetate, acidified with 2N=hydrochloric acid and extracted with ethyl acetate. The dried organic solution was evaporated to a small bulk and added dropwise to stirred petroleum spirit (b.p. 40°-60°). The resulting precipitate was collected, washed and dried to give the title acid (0.56 g., 55% based on amine), [α]D + 243° (c 0.93, DMSO), λmax. (pH 6 buffer) 275 nm (ε 9,600) νmax. (Nujol), 1778 (β-lactam), 1740 and 2600 (CO2H), 1670 and 1528 cm.-1 (CONH), τ (d6 -DMSO) values include 0.44 (d, J 6 Hz; NH) 2.18 and 3.34 (multiplets; aromatic protons), 5.70 (s; C-3H), 8.36 and 8.46 (2s; CH3 groups).

Provenance & Evidence