反应详情

To a solution of pyridine (1.5 ml.) in ethyl acetate (20 ml.) was added 3-acetoxymethyl-7β-(2-hydroxyimino-2-phenylacetamido)ceph-3-em-4-carboxylic acid (syn-isomer) (0.5 g.) and the stirred mixture was treated dropwise with a solution of acetyl chloride (1.0 ml.) in ethyl acetate (5 ml.) and stirring continued for ten minutes. The mixture was poured into water, the ethyl acetate phase separated and washed with 2 N-hydrochloric acid, water, and extracted with saturated aqueous sodium bicarbonate. The combined aqueous extracts were acidified and extracted with ethyl acetate and the extracts were dried and concentrated to ca. 5 ml. The concentrate was added dropwise with stirring to petroleum (250 ml.). The precipitated solid was collected and dried, giving the title acid (0.32 g; 58%), [α]D +83° (c C.8, DMSO), λmax. (pH 6 buffer) 258 nm (ε 20,800), νmax. (Nujol) 3270 (NH), 1780 (β-lactam), 1680 and 1546 cm.-1 (CONH), τ (DMSO-d6) values include -0.10 (doublet J 8 Hz; NH), 2.2 to 2.6 (multiplet; aromatic protons), 7.78 (singlet; --N.O.COCH3), 7.94 (singlet; OCOCH3).

1. waitcontinued for ten minutes
2. customthe ethyl acetate phase separated
3. washwashed with 2 N-hydrochloric acid, water
4. extractionextracted with saturated aqueous sodium bicarbonate
5. extractionextracted with ethyl acetate
6. customthe extracts were dried
7. concentrationconcentrated to ca. 5 ml
8. additionThe concentrate was added dropwise
9. stirringwith stirring to petroleum (250 ml.)
10. customThe precipitated solid was collected
11. customdried
12. customgiving the title acid (0.32 g; 58%), [α]D +83° (c C.8, DMSO), λmax