p-Toluenesulfonic acid → Methyl 5-(5-methoxy-1,4,5,6-tetrahydrocyclopenta[d]imidazol-2-yl)-2,4-dimethylbenzoate

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Reaction Steps

Into around-bottom flask, was placed a solution of methyl 5-(3a-hydroxy-5-methoxy-1,3a,4,5,6,6a-hexahydrocyclopenta[d]imidazol-2-yl)-2,4-dimethylbenzoate (compound 461.5, 200 mg, 0.38 mmol, 1.00 equiv, 60%) in N,N-dimethylformamide (mL). p-Toluenesulfonic acid (20 mg, 0.12 mmol, 0.18 equiv) was added and the resulting solution was stiffed overnight at 80° C., then concentrated in vacuo. The residue was purified by silica gel chromatography with dichloromethane/methanol (10:1) as the eluent to obtain the title compound as a brown oil (100 mg, 66%).

Provenance & Evidence