Isopropyl iodide → Ethyl 5-iodo-1-isopropyl-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of ethyl 3-iodopyrazole-4-carboxylate (1.58 g, 5.94 mmol, Truong; et al. Bioorg. Med. Chem. Lett., 19, 4920 (2009)) in 20 mL N,N-dimethylformamide was added cesium carbonate (3.87 g, 11.9 mmol) and 2-iodopropane (0.89 mL, 8.90 mmol). The mixture was stirred 2 hours at 60° C. and then cooled to ambient temperature. The reaction mixture was diluted with 150 mL water and extracted with 2×100 mL diethyl ether. The combined organics were washed with 50 mL brine, dried over sodium sulfate, filtered and concentrated. The resultant oil was purified by flash chromatography (7-60% ethyl acetate/heptane gradient, 50 g silica) to yield 340 mg of ethyl 5-iodo-1-isopropyl-1H-pyrazole-4-carboxylate as a clear oil which crystallized on standing and 740 mg of ethyl 3-iodo-1-isopropyl-1H-pyrazole-4-carboxylate as a clear oil.

Provenance & Evidence