反应详情

Sodium cephalothin (2.09 g, 5.0 mmole), 5-mercapto-1,3,4-oxadiazol-2-ylacetamide (0.84 g., 5.5 mmole) and sodium bicarbonate (0.42 g., 5.0 mmole) in pH 6.5 phosphate buffer (25 ml) were heated at 60° C. for 6.5 hours, then poured onto crushed ice (~25 g), washed with ethyl acetate (2×20 ml), acidified to pH 2.0 with N hydrochloric acid and extracted with ethyl acetate (3×50 ml). The extracts were washed with water (2×20 ml) and saturated brine (20 ml), dried and evaporated to dryness in vacuo to give a gummy solid. This was extracted with hot ethyl acetate (10 ml) to leave the product as an off white solid, 1.23 g., 49.8%; t.l.c. (SiO2 ; n-butanol, acetic acid, water; 12:3:5) Rf=0.41; λmax (95% ethanol), 272 nm (εm=9,650); δ[(CD3)2SO], 3.5-4.0 (2H,m, C2 methylene), 3.85 and 3.90 (4H, 2×s, 2×--CH2CO--), 4.33 and 4.49 (2H, AB quartet, J=14 Hz, --CH2S--), 5.22 (1H,d, J=5 Hz, C6 proton), 5.81 (1H,dd, J=5,8 Hz, C7 proton), 7.0-7.6 (3 H,m, thienyl protons), 7.65 (2H, d, J=26 Hz, --CONH2 ), 9.33 (1H,d, J=8 Hz, --CONH--).

1. additionpoured
2. washwashed with ethyl acetate (2×20 ml)
3. extractionextracted with ethyl acetate (3×50 ml)
4. washThe extracts were washed with water (2×20 ml) and saturated brine (20 ml)
5. customdried
6. customevaporated to dryness in vacuo
7. customto give a gummy solid
8. extractionThis was extracted with hot ethyl acetate (10 ml)
9. customto leave the product as an off white solid, 1.23 g