反应详情

Under argon, 200 g (0.72 mol) of 3-(benzyloxy)-5-bromopyridine-2-amine Example 84A, 590 g (3.58 mol) of ethyl 2-chloroacetoacetate and 436 g 3 A molecular sieve were suspended in 6 l of ethanol and boiled at reflux for 72 h. The reaction mixture was filtered off through kieselguhr and concentrated. The residue was purified by silica gel chromatography (petroleum ether:ethyl acetate 9:1, then 6:4) and the product fractions were concentrated. This gave 221 g (79% of theory) of the target compound.

1. temperatureat reflux for 72 h
2. filtrationThe reaction mixture was filtered off through kieselguhr
3. concentrationconcentrated
4. customThe residue was purified by silica gel chromatography (petroleum ether:ethyl acetate 9:1
5. concentration6:4) and the product fractions were concentrated