1: diethyl ether / 2 h / 0 °C 2: 4 M NaOH / dioxane; H2O / Ambient temperature; overnight 3: CF3COOH / dioxane; H2O / 8 h / 100 °C 4: 36.7 g / 4-dimethylaminopyridine / pyridine / 1. 0 deg C, 4 h, 2. room temperature, 20 h 5: pyridine / 1. 0 deg C, 2 h; 2. room temperature, overnight 6: 1. NaH / 1. DMF, 80 deg C, 1 h, 2. 100 deg C, 24 h View Scheme

1: 36.7 g / 4-dimethylaminopyridine / pyridine / 1. 0 deg C, 4 h, 2. room temperature, 20 h 2: pyridine / 1. 0 deg C, 2 h; 2. room temperature, overnight 3: 1. NaH / 1. DMF, 80 deg C, 1 h, 2. 100 deg C, 24 h View Scheme

sodium hydride 1. DMF, 80 deg C, 1 h, 2. 100 deg C, 24 h; Yield given. Multistep reaction;