反应详情

To a solution of vanillin (2.0 g, 13.2 mmol) in ethanol (15 ml) was added dropwise a solution of cysteamine HCl (0.5 g, 4.4 mmol) in water (5 ml) and the solution stirred at RT for 16.5 h. The bulk of the ethanol was removed by rotary evaporator and the residue was diluted with water (15 ml) and extracted with diethyl ether (3×20 ml) to remove excess aldehyde. The aqueous layer was basified by addition of solid sodium carbonate (0.3 g) causing the product to precipitate out of solution. The precipitate was filtered, washed carefully with water (3×20 ml) and dried in a vacuum desiccator to give 2-(4-hydroxy-3-methoxyphenyl)-1,3-thiazolane (7) as a white solid (0.62 g, 67%), mp 158-161° (lit mp, 182-183°). 1H nmr (d6-dmso, 300 MHz) 2.8-3.0, m, H4,4,5; 3.12, br s, NH; 3.4-3.6, m, H5; 3.76, s, OMe; 5.34, s, H2; 6.70, d (8.0 Hz), H5′; 6.84, dd (1.8, 8.1 Hz), H6′; 7.04, d (1.8 Hz), H2′; 8.91, s, OH. ESI (+ve) MS m/z 212 (M+H, 100%).

1. customThe bulk of the ethanol was removed by rotary evaporator
2. additionthe residue was diluted with water (15 ml)
3. extractionextracted with diethyl ether (3×20 ml)
4. customto remove excess aldehyde
5. additionThe aqueous layer was basified by addition of solid sodium carbonate (0.3 g)
6. customto precipitate out of solution
7. filtrationThe precipitate was filtered
8. washwashed carefully with water (3×20 ml)
9. customdried in a vacuum desiccator