反应详情

A mixture of 5-amino-1,2,4-thiadiazole (1 g; 9.89 mmol) and 2,4-dimethoxybenzaldehyde (1.81 g; 10.9 mmol) in toluene (30 ml) was refluxed under Dean and Stark conditions for 2 hours. The reaction mixture was evaporated, the residue taken up in methanol (25 ml), NaBH4 (600 mg; 15.9 mmol) added carefully in small portions (vigorous effervescence after each addition), and the reaction was left stirring overnight at ambient temperature. Aqueous HCl (2M, 1 ml) was added followed by aqueous NaOH (2M, 10 ml). The bulk of the methanol was evaporated, water (20 ml) added and extracted with ethyl acetate (2×30 ml). The combined organic was washed brine (20 ml), dried, and evaporated. The residue was purified by silica gel column chromatography (ISCO™ column 120 g; ethyl acetate:heptane 25:75 to 60:40) to furnish a semi-solid residue that was re-evaporated from heptane. 2-3 ml tBuOMe was added, then 2-3 ml heptane, the solid filtered off, washed with heptane and dried to afford 1.22 g of the title compound.

1. temperaturewas refluxed under Dean and Stark conditions for 2 hours
2. customThe reaction mixture was evaporated
3. additionafter each addition), and the reaction
4. waitwas left
5. customThe bulk of the methanol was evaporated
6. additionwater (20 ml) added
7. extractionextracted with ethyl acetate (2×30 ml)
8. washThe combined organic was washed brine (20 ml)
9. customdried
10. customevaporated
11. customThe residue was purified by silica gel column chromatography (ISCO™ column 120 g; ethyl acetate:heptane 25:75 to 60:40)
12. customto furnish a semi-solid residue that
13. customwas re-evaporated from heptane
14. addition2-3 ml tBuOMe was added
15. filtration2-3 ml heptane, the solid filtered off
16. washwashed with heptane
17. customdried