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Stage #1: With pyridine; dmap In ethanol for 48 h; Inert atmosphere; Schlenk technique; Reflux Stage #2: With pyrrolidine In ethanol at 20℃; for 16 h; Inert atmosphere; Schlenk technique; Reflux
A mixture of 2-aminobenzaldehyde (6.0 g, 49.58 mmol), 1-(2-oxopropyl)pyridinium chloride (8.98 g, 52.06 mmol), pyridine (2.6 ml, 32.72 mmol) and 4-dimethylaminopyridine (60 mg, 0.49 mmol) in ethanol (75 ml) were refluxed for 48 h. The reaction mixture was cooled to room temperature and pyrrolidine (10.3 ml, 123.96 mmol) was added, and mixture was then refluxed for 16 h. The volatiles were removed under reduced pressure and the resultant mixture was diluted with aqueous sodium bicarbonate solution (200 ml). The mixture was extracted with dichloromethane (2 x 200 ml). The combined organic layers were washed with brine (200 ml) and dried over anhydrous sodium sulphate. The organic layer was filtered and concentrated under reduced pressure. The residue obtained was purified by flash silica gel column chromatography to yield 4.8 g of product as a yellow solid.
Reference:
[1] Bioorganic and Medicinal Chemistry Letters, 2014, vol. 24, # 9, p. 2073 - 2078
With ammonium acetate In methanol for 12h; Reflux;
With ammonium acetate In methanol for 12h; Reflux;
1.1 Synthesis of Compound A2:
Compound A1, pyridine salt, ammonium acetate and mixing dry methanol, the reflux 12h, filtration, drying after solid was washed with methanol and water, to give a white product, dried to obtain the compound A2, where A1 is a compound (1E, 5E) -1.6- bis (2-furyl) -1,5-hexadiene-3,4-dione
A mixture of 2-aminobenzaldehyde (6.0 g, 49.58 mmol), 1-(2-oxopropyl)pyridinium chloride (8.98 g, 52.06 mmol), pyridine (2.6 ml, 32.72 mmol) and 4-dimethylaminopyridine (60 mg, 0.49 mmol) in ethanol (75 ml) were refluxed for 48 h. The reaction mixture was cooled to room temperature and pyrrolidine (10.3 ml, 123.96 mmol) was added, and mixture was then refluxed for 16 h. The volatiles were removed under reduced pressure and the resultant mixture was diluted with aqueous sodium bicarbonate solution (200 ml). The mixture was extracted with dichloromethane (2 x 200 ml). The combined organic layers were washed with brine (200 ml) and dried over anhydrous sodium sulphate. The organic layer was filtered and concentrated under reduced pressure. The residue obtained was purified by flash silica gel column chromatography to yield 4.8 g of product as a yellow solid.