Bromine → 2-(Methylamino)-1,3-benzothiazole-7-carboxylic acid
反応式
BrBr.[CH3:3][NH:4][C:5](=[S:16])[NH:6][C:7]1[CH:8]=[C:9]([CH:13]=[CH:14][CH:15]=1)[C:10]([OH:12])=[O:11]>C(O)(=O)C>[CH3:3][NH:4][C:5]1[S:16][C:8]2[C:9]([C:10]([OH:12])=[O:11])=[CH:13][CH:14]=[CH:15][C:7]=2[N:6]=1参加物
4
反応条件
- 温度
- 95 °C
実験手順
A solution of 163 g of bromine and 50 g of 100% acetic acid is added dropwise to a suspension of 212 g of 3-(N′-methylthioureido)-benzoic acid and 500 g of 100% acetic acid at 45-50° C. in the course of 2 hours. The mixture is then heated to 90-100° C. in the course of 2.5 hours and is allowed to react for a further 2 hours until the release of the gas has ended. After 150 g of acetic acid have been distilled off at 80-85° C. under reduced pressure, 200 g of water are added and the mixture is brought to pH 2 by dropwise addition of 30% sodium hydroxide solution. Filtration with suction at 70-80° C. and washing with water gives 179.2 g of the title compound of melting point: >330° C. HPLC analysis shows a content of 94.6% of the title compound, in addition to 3-4% of isomeric 2-methylamino-benzothiazole-5-carboxylic acid.