sodium ethanolate in ethanol T=50°C;

1: sodium methoxide / methanol / Ambient temperature; overnight 2: acetonitrile / 2 h / Heating View Scheme

1: 90 percent / NaOMe / methanol / 24 h / Ambient temperature 2: 71 percent / pyridine / 1.25 h / Ambient temperature 3: 65 percent / tetrabutylammonium hydroxide, pyridine / acetonitrile / 48 h / Heating 4: 1.) NaH / 1.) DMF, -40 deg C, 0.75 h, 2.) DMF, a) from -40 to -30 deg C, 0.75 h, b) RT, 4 h 5: 71 percent / potassium t-butoxide / CH2Cl2 / 1.5 h / Ambient temperature 6: 75 percent / diisopropylethylamine / tetrahydrofuran / 4.5 h View Scheme