Potassium Carbonate → 4-Iodo-1-(5,8-dioxaspiro[3.4]octan-2-yl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-bromo-5,8-dioxa-spiro[3.4]octane (Compound 100F, 19 g, 100 mmol) and 4-iodopyrazole (38.6 g, 200 mmol) in DMF (100 mL) was added powdered K2CO3 (41.4 g, 300 mmol) and 18-crown-6 ether (5.3 g, 20 mmol). The reaction mixture was stirred at 85-90° C. for 2 days. The reaction mixture was diluted with ethyl acetate (400 mL) and washed with water (4×100 mL). The combined organic layers were washed with brine and concentrated, the residue was purified by column chromatography (ethyl acetate/DCM: 5:95) to give 8.8 g (29%) of 1-(5,8-dioxa-spiro[3.4]oct-2-yl)-4-iodo-1H-pyrazole. 1H NMR (CDCl3, 300 MHz): δ=2.87-2.89 (m, 4H), 3.92-3.96 (m, 4H), 4.64-4.68 (m, 1H), 7.53 (s, 2H).

Provenance & Evidence