Methyl p-toluenesulfonate → 2-(Methylsulfanyl)-1,3-benzothiazol-5-ol
反応式
[SH:1][C:2]1[S:3][C:4]2[CH:10]=[CH:9][C:8]([O:11]C)=[CH:7][C:5]=2[N:6]=1.[C:13]1(C)C=CC(S(OC)(=O)=O)=CC=1>CC#N>[OH:11][C:8]1[CH:9]=[CH:10][C:4]2[S:3][C:2]([S:1][CH3:13])=[N:6][C:5]=2[CH:7]=1参加物
4
実験手順
To a 250 mL flask was added 2-mercapto-5-methoxybenzothiazole (5.1 g, 26 mmol), MeCN (63 mL), methyl p-toluenesulfonate (4.8 g, 26 mmol) and TEA (4.4 mL, 31 mmol). After stirring 16 h at ambient temperature, the solution was concentrated under reduced pressure. The crude material was diluted with EtOAc (200 mL), washed with water (2×75 mL), dried over Na2SO4, filtered, and concentrated. The resulting viscous oil was dissolved in DCM (40 mL), and transferred to an argon-purged 250 mL flask. The solution was cooled to −78° C. prior to the addition of a 1.0 M BBr3 solution in DCM (64 mL). The reaction suspension was allowed to warm to room temperature. After 16 h the reaction solution was cooled to −78° C. and quenched by addition of MeOH (100 mL). The resulting precipitates were isolated by vacuum filtration to yield 5-hydroxy-2-methylthio-benzothiazole (3.9 g, 76%) as a white solid.