4-(chloromethyl)-1,3-dioxolan-2-one

Conditions: temp:65.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 6.5 g of the compound of Example 1 in 50 ml of dimethylformamide are added 4.1 g of potassium carbonate and 4.1 g of 4-chloromethyl-2-oxo-1,3-dioxolane, and the mixture is stirred at 65° C. for 4 hours. After completion of the reaction, the reaction mixture is poured into ice-cold water, and the precipitate is extracted with ethyl acetate. The extract is washed with water, dried and concentrated, and then the obtained residue is recrystallized from isopropyl ether to give 6 g of 3-(3,5-di-tertiary butyl-4-hydroxyphenyl)-1-(2-oxo-1,3-dioxolan-4-ylmethyl)-1H-pyrazolo[3,4-b]pyridine as white crystals, melting at 140°-141° C. After completion of the reaction the reaction mixture is poured into ice-cold water the precipitate is extracted with ethyl acetate The extract is washed with water dried concentrated the obtained residue is recrystallized from isopropyl ether