m-Chloroperbenzoic acid → 1-ethyl-4-chloro-6-(methylsulfinyl)-1H-pyrazolo[3,4-b]quinoline

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-ethyl-4-chloro-6-(methylthio)-1H-pyrazolo[3,4-b]quinoline (2.4 g, 8.7 mmol) in CHCl3 (50 ml) at -40° C. is added m-chloroperoxybenzoic acid (2.75 g, 8.7 mmol). The reaction mixture is slowly warmed to 0° C. and then saturated NaHCO3 (10 ml) is added. The reaction mixture is partitioned between water (20 ml) and CH2Cl2 (20 ml), the layers are separated and then the aqueous layer is extracted with CH2Cl2 (20 ml). The CH2Cl2 extracts are combined, dried over MgSO4 and evaporated. The residue is purified by column chromatography on silica gel eluting with 50% ether/hexane, then 25% ethyl acetate/25% hexane/50% ether and finally ethyl acetate (100%) to afford 2.4 g of 1-ethyl-4-chloro-6-(methylsulfinyl)-1H-pyrazolo[3,4-b]quinoline.

Provenance & Evidence