Réaction #43996

Équation de réaction

n-Butyl lithium

2-bromo-1,4-dimethoxy-3-methylnaphthalene

ethyl chloroformate

→

ethyl 1,4-dimethoxy-2-methylnaphthalene-3-carboxylate

Rendement 89.0%

Solvants

tetrahydrofuran

Conditions de réaction

Traitement

1. 1
   Autrequenched by addition of hydrochloric acid (2N)
2. 2
   Extractionextracted with ethyl acetate
3. 3
   SéchageThe extract was dried (Na2SO4)
4. 4
   Autrethe solvent evaporated under vacuum
5. 5
   AutreThe residue was purified by SPE (silica, 10 g)
6. 6
   Lavageeluting with 10% ethyl acetate in cyclohexane

Mode opératoire

n-Butyl lithium (1.6M in hexanes, 4.1 ml, 6.56 mmol) was added dropwise to 2-bromo-1,4-dimethoxy-3-methylnaphthalene (1.537 g, 5.47 mmol) in tetrahydrofuran (30 ml) at −50° C. The reaction was stirred for 30 min at −50° C. before dropwise addition of ethyl chloroformate (1 ml, 10.46 mmol). The reaction was allowed to warm to 0° C. over 18 h quenched by addition of hydrochloric acid (2N) and extracted with ethyl acetate. The extract was dried (Na2SO4) and the solvent evaporated under vacuum. The residue was purified by SPE (silica, 10 g) eluting with 10% ethyl acetate in cyclohexane to give ethyl 1,4-dimethoxy-2-methylnaphthalene-3-carboxylate (1.33 g, 89%).

Source