Isocyanate → HCID 131710765, compound

Participants

Reaction Steps

To ethyl ioscyanate (5 ml.) was added (3-acetoxymethyl-7β-(2-hydroxyimino-2-phenylacetamido)ceph-3-em-4-carboxylic acid ethyl acetate solvate (syn-isomer) (0.9 g.) and the mixtue stirred for one hour at room temperature. Two further portions of the isocyanate (5 ml.) were added, over a period of 2 hours. The mixture was then allowed to stand for 1 hour, and poured into petroleum (b.p. 40°-60°; 250 ml.) and the resulting precipitate collected, washed thoroughly with petroleum and dried. The solid was dissolved in ethyl acetate and extracted into sodium bicarbonate solution; the bicarbonate solution was then washed with ethyl acetate, acidified (2N-hydrochloric acid) and extracted with ethyl acetate. The combined extracts were dried and concentrated, and the concentrate (ca. 5 ml.) added dropwise to petroleum spirit with vigorous stirring. The precipitate formed was filtered and dried, giving the title acid (0.4 g., 47%), [α]D + 50° (c 0.85, DMSO), νmax. (pH 6 buffer) 257.5 nm (ε 21,200), νmax. (Nujol) 1782 (β-lactam), 1675 and 1520 cm.-1 (CONH), τ (DMSO-d6) values include 0.04 (doublet J 8 Hz; NH), 2.0-2.6 (multiplet; aromatic protons), 6.7-7.1 (multiplet; NHCH2CH3) and 8.89 (triplet, J 9 Hz; (CH2CH3).

Provenance & Evidence