Pyridinium chloride → 7-Methylbenzo[d]isothiazol-4-ol
Reaction equation
S1C2=CC=CC(O)=C2C=N1.C[O:12][C:13]1[C:18]2[CH:19]=[N:20][S:21][C:17]=2[C:16]([CH3:22])=[CH:15][CH:14]=1.Cl.N1C=CC=CC=1>>[CH3:22][C:16]1[CH:15]=[CH:14][C:13]([OH:12])=[C:18]2[C:17]=1[S:21][N:20]=[CH:19]2Participants
Procedure
A solution of 7-4-methoxy-benzo[d]isothiazole (460 mg, 1.88 mmol), K2CO3 (780 mg, 5.64 mmol), and Pd(PPh3)4 (217 mg, 0.188 mmol) in 1,4-dioxane (5 mL) was added trimethylboroxine (290 μL, 2.07 mmol) and the solution was heated to 110° C. for 18 h. The reaction was cooled to rt and diluted with water and dichloromethane. The organic phase was separated and the aqueous phase was extracted with 2×30 mL dichloromethane. The combined organic phases were dried (MgSO4) and concentrated in vacuo. The residue was purified by flash chromatography eluting silica gel with EtOAc:hexane [0:100 to 1:10] to yield 4-methoxy-7-methyl-benzo[d]isothiazole (88 mg, 26%). A method similar to that described for the preparation of benzo[d]isothiazol-4-ol (above) using 4-methoxy-7-methyl-benzo[d]isothiazole (88 mg, 0.491 mmol) and pyridine hydrochloride (567 mg, 5 mol) gave the title compound (30 mg, 37%): δH (300 MHz, CDCl3): 8.99 (1H, s), 7.15 (1H, d, J=7.5 Hz), 6.70 (1H, d, J=7.5 Hz), 2.45 (3H, s).
Sources & evidence
- ORD record
- ord-fc2c050f43394ab5bf81704c8784caa8
- Source dataset
- uspto-grants-2008_08
- Patent number
- US07410982B2
Reaction notes
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