Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1) → 3-(4-iodo-1H-pyrazol-1-yl)cyclobutan-1-one
Reaction equation
[CH2:1]1[C:4]2(OCC[O:5]2)[CH2:3][CH:2]1[N:9]1[CH:13]=[C:12]([I:14])[CH:11]=[N:10]1.C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>O1CCOCC1.O>[I:14][C:12]1[CH:11]=[N:10][N:9]([CH:2]2[CH2:1][C:4](=[O:5])[CH2:3]2)[CH:13]=1Participants
4
Procedure
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, 2 H), 3.73-3.77 (m, 2 H), 5.0-5.02 (m, 1 H), 7.56 (s, 1 H), 7.58 (s, 1 H).