反应详情

2-(4-Benzyloxy-3,5-dimethyl-phenyl)-5-(5-isobutyl-thiophen-2-yl)-[1,3,4]oxadiazole is prepared in analogy to Example 21 step a) and b) by coupling and cyclising 5-isobutyl-thiophene-2-carboxylic acid with 4-benzyloxy-3,5-dimethyl-benzoic acid hydrazide, LC-MS: tR=1.06 min, [M+1]+=437.17. To a solution of this compound (2.83 g, 6.75 mmol) in EtOH (50 mL) and THF (50 mL) is added Pd/C (10% Pd, 400 mg) and the slurry is stirred at rt for 48 h under 5 bar of H2. The mixture is filtered, the filtrate is concentrated and the crude product is purified by CC on silica gel eluting with heptane:EA 8:25 to give 4-[5-(5-isobutyl-thiophen-2-yl)-[1,3,4]oxadiazol-2-yl]-2,6-dimethyl-phenol (943 mg) as a white powder; LC-MS: tR=1.09 min, [M+1]+=329.36.

1. filtrationThe mixture is filtered
2. concentrationthe filtrate is concentrated
3. customthe crude product is purified by CC on silica gel eluting with heptane:EA 8:25