反应详情

Sodium 7-(thien-3-ylacetamido)-3-acetoxymethylceph-3-em-4-carboxylate (1.90 g, 4.6 mmole), 5-mercapto-1H-tetrazol-1-ylacetamide (0.81 g, 5.1 mmole) and sodium bicarbonate (0.42 g, 5 mmole) in pH 6.5 phosphate buffer (25 ml) were heated at 60° for 6 hours, then poured onto ice, washed with ethyl acetate (25 ml), acidified to pH 1.5 and extracted with ethyl acetate (3×20 ml). The extracts were washed with water and saturated brine, dried, evaporated to dryness and the residue triturated with anhydrous ether to give the free acid, 1.59 g. This was dissolved in acetone (25 ml), treated with 2 N sodium 2-ethylhexoate in 4-methylpentan-2-one (1.5 ml), diluted with anhydrous ether (25 ml) and the precipitated sodium salt collected, washed with ether and dried, 1.00 g, 42.1% yield; t.l.c. (SiO2 ; B.A.W; 12:3:5) Rf=0.40; λmax (95% ethanol) 273 nm (ε=8,200); δ[(CD3)2SO] 3.2-3.7 (2H,m, C2 methylene), 3.38 (2H,s, --CH2CONH--), 4.04-4.25 (2H, ABq, J 13 Hz, --CH2S--), 4.73 (1H,d, J 5 Hz, C6 proton), 4.87 (2H,s, --CH2CONH2), 5.50 (1H,dd, J 5 and 8 Hz, C7 proton), 6.9-8.2 (5H,m, thienyl protons and --CONH2), 8.88 (1H,d, J 8 Hz, --CONH--).

1. additionpoured onto ice
2. washwashed with ethyl acetate (25 ml)
3. extractionextracted with ethyl acetate (3×20 ml)
4. washThe extracts were washed with water and saturated brine
5. customdried
6. customevaporated to dryness
7. customthe residue triturated with anhydrous ether
8. customto give the free acid, 1.59 g
9. customthe precipitated sodium salt collected
10. washwashed with ether
11. customdried