Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → 3-(4-iodo-1H-pyrazol-1-yl)cyclobutan-1-one

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Reaction Steps

A solution of 1-(5,8-dioxa-spiro[3.4]oct-2-yl)-4-iodo-1H-pyrazole (Compound 100E, 8.8 g, 29 mmol) and pyridinium p-toluenesulfonate (21 g, 87 mmol) in dioxane-water (140 mL of 1:1 mixture) was stirred at 85° C. for 12 h. The reaction mixture was concentrated and diluted with ethyl acetate (100 mL), the organic layer was washed with water (2×50 mL), dried (Na2SO4) and concentrated to give 6.5 g (yield: 86%) of 3-(4-iodo-1H-pyrazol-1-yl)cyclobutanone. 1H NMR (CDCl3, 300 MHz): δ=3.53-3.57 (m, 2H), 3.73-3.77 (m, 2H), 5.0-5.02 (m, 1H), 7.56 (s, 1H), 7.58 (s, 1H).

Provenance & Evidence