6-[Acetoxy-(2,3-dihydro-benzo[4,5]imidazo[2,1-b]thiazol-6-yl)-methyl]-6-bromo-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester → (5R,6Z)-6-(2,3-dihydro[1,3]thiazolo[3,2-a]benzimidazol-6-ylmethylene)-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid

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Reaction Steps

6-[Acetoxy-(2,3-dihydro-benzo[4,5]imidazo[2,1-b]thiazol-6-yl)-methyl]-6-bromo-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester (690 mg, 1.1 mmol) was suspended in 20 ml THF and 20 ml pH=6.5 aqueous phosphate buffer. The mixture was then subjected to 45 psi hydrogen for two hours. Then it was filtered through a pad of celite and concentrated in vacuo to remove most of the THF. The solution was then cooled to zero degree and basified to pH=8 with 1 N sodium hydroxide. Then it was purified via reverse phase HPLC using 1 liter of water followed by 5%-25% acetonitrile and water. Water was then removed through concentrate in vacuo and 32 mg of product (Yield 3%) was collected. MP: >250° C.; H-NMR(D2O): □ 7.08(m, 6H), 7.36(s, 1H), 4.05(m, 2H), 3.90(b, 1H); MS: 358.3 (M+H).

Provenance & Evidence