m-Chloroperbenzoic acid → 8-benzyloxy-2-ethyl-1-methyl-5-oxido-1H-imidazo[4,5-c]quinoline

Participants

Reaction Steps

A modification of the general method described in Part B of Example 3 was followed. mCPBA (60% pure, 1.39 g, 47.3 mmol) was added in portions to a solution of 8-benzyloxy-2-ethyl-1-methyl-1H-imidazo[4,5-c]quinoline (1.5 g, 47 mmol) in chloroform (75 mL), and the reaction was stirred for 5.5 hours. During the work-up, the combined aqueous washings were extracted with dichloromethane, and the product precipitated from solution. The combined dichloromethane and chloroform solutions were concentrated under reduced pressure until crystals formed and then allowed to stand overnight. The crystals were isolated by filtration. The aqueous solution was extracted with chloroform, and the combined extracts were washed with water (2×) and concentrated under reduced pressure to a small volume. Hexanes were added, and the resulting crystals were isolated by filtration. The mother liquor was concentrated under reduced pressure to afford a solid that was recrystallized from 2-propanol. The three batches of crystals were combined to yield 1.30 g of 8-benzyloxy-2-ethyl-1-methyl-5-oxido-1H-imidazo[4,5-c]quinoline.

Provenance & Evidence