Methyl 4-chloroformylbutyrate → 2-(5-methoxycarbonyl-2-oxopentylidene)-3-methyl-3H-benzothiazole
反応式
S(C1C=CC(C)=CC=1)([O-])(=O)=O.[CH3:12][C:13]1[S:14][C:15]2[CH:22]=[C:21](S(O)(=O)=O)[CH:20]=[CH:19][C:16]=2[N+:17]=1[CH3:18].Cl[C:28](=[O:36])[CH2:29][CH2:30][CH2:31][C:32]([O:34][CH3:35])=[O:33]>N1C=CC=CC=1>[CH3:35][O:34][C:32]([CH2:31][CH2:30][CH2:29][C:28](=[O:36])[CH:12]=[C:13]1[N:17]([CH3:18])[C:16]2[CH:19]=[CH:20][CH:21]=[CH:22][C:15]=2[S:14]1)=[O:33]参加物
4
反応条件
- 温度
- 55 °C
実験手順
To 1.7 g of 2,3-dimethyl-6-sulfobenzothiazolium tosylate in 20 mL of pyridine at room temperature is added 1 mL of methyl 5-chloro-5-oxovalerate. The mixture is heated at 50-60° C. for 3 hours. The pyridine solvent is removed under reduced pressure, and the reaction is worked up with chloroform and brine, and purified by silica gel column to yield 0.5 g of 2-(5-methoxycarbonyl-2-oxopentylidene)-3-methyl-3H-benzothiazole. A mixture of 0.45 g of this benzothiazole and 0.45 g of phosphorous oxychloride in 5 mL of dichloroethane is heated at reflux for 2 hours to generate 2-(2-chloro-2-methoxycarbonylpropylvinyl)-3-methylbenzothiazolium chloride. The volatile components are evaporated and the crude chloride is used without further purification. The crude chloride and 0.5 g of Compound 12 is stirred in 5 mL of dichloroethane in the presence of 0.45 mL of triethylamine for 2 hours. The volatile components are removed under reduced pressure, and the residue is dissolved in 5 mL of methanol and added dropwise to a solution of 4.5 g of sodium iodide in 30 mL water. The sticky solid is purified by HPLC to yield Compound 37.