反应详情

A mixture of 5-amino-1,2,4-thiadiazole (1.00 g, 9.89 mmol) and 2,4-dimethoxybenzaldehyde (1.81 g, 10.9 mmol) in toluene (30 mL) was refluxed under Dean-Stark conditions for 2 hours. The reaction mixture was concentrated in vacuo, and the resulting residue taken up in methanol (25 mL). Sodium borohydride (600 mg, 15.9 mmol) was added carefully in small portions (vigorous effervescence after each addition) and the reaction was left to stir overnight at ambient temperature. An 2M aqueous solution of hydrogen chloride (1 mL) was added followed by a 2M aqueous solution of sodium hydroxide (10 mL). The mixture was concentrated in vacuo, water (20 mL) added and the mixture extracted with ethyl acetate (2×30 mL). The combined organics were washed with brine (20 mL), dried, and concentrated in vacuo. The residue was purified by silica gel column chromatography (ISCO™ column, 25% to 60% ethyl acetate in heptane gradient elution) to furnish a semi-solid residue. tert-Butylmethyl ether (2-3 mL) was added, followed by heptane (2-3 mL). The resulting solid was collected by filtration, washed with heptane and dried to afford the title compound (1.22 g).

1. temperaturewas refluxed under Dean-Stark conditions for 2 hours
2. concentrationThe reaction mixture was concentrated in vacuo
3. additionafter each addition) and the reaction
4. waitwas left
5. concentrationThe mixture was concentrated in vacuo, water (20 mL)
6. additionadded
7. extractionthe mixture extracted with ethyl acetate (2×30 mL)
8. washThe combined organics were washed with brine (20 mL)
9. customdried
10. concentrationconcentrated in vacuo
11. customThe residue was purified by silica gel column chromatography (ISCO™ column, 25% to 60% ethyl acetate in heptane gradient elution)
12. customto furnish a semi-solid residue
13. filtrationThe resulting solid was collected by filtration
14. washwashed with heptane
15. customdried