反应详情

N,N-Dimethyl acetoacetamide (46.8 g; 0.363 mole) was converted to its dianion by treatment with 80% sodium hydride (11.8 g; 0.393 mole) in dry tetrahydrofuran (350 ml) under nitrogen, at 20° C. The resulting suspension was diluted with dry ether (1 L) and stirred mechanically for 15 minutes at 0° C. before a solution of n-butyl lithium in hexane (227 ml; 1.6 M; 0.363 mole) was added dropwise. To the now clear mixture was then added 3-chloromethyl thiophene (38 g; 0.287 mole) in dry tetrahydrofuran (50 ml), again dropwise, and the reaction allowed to warm up to room temperature. After the solution had stood at room temperature overnight the solvents were removed on a rotary evaporator and the residue acidified with dilute HCl in the presence of ethyl acetate (200 ml). The organic layer was separated off and the aqueous layer extracted once again with ethyl acetate (200 ml). The combined organic layers were dried (anhydrous MgSO4), and evaporated to give an oil which was purified on a short silica gel column using chloroform as eluant affording the product as a red-brown oil (48.5 g; 75%).

1. additionwas added dropwise
2. customthe solvents were removed on a rotary evaporator
3. customThe organic layer was separated off
4. extractionthe aqueous layer extracted once again with ethyl acetate (200 ml)
5. dry with materialThe combined organic layers were dried (anhydrous MgSO4)
6. customevaporated
7. customto give an oil which
8. customwas purified on a short silica gel column