Reaction #43996

Reaction equation

n-Butyl lithium

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

ethyl chloroformate

→

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

Yield 89.0%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Otherquenched by addition of hydrochloric acid (2N)
2. 2
   Extractionextracted with ethyl acetate
3. 3
   DryingThe extract was dried (Na2SO4)
4. 4
   Otherthe solvent evaporated under vacuum
5. 5
   OtherThe residue was purified by SPE (silica, 10 g)
6. 6
   Washeluting with 10% ethyl acetate in cyclohexane

Procedure

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