phosphoric acid; sodium nitrite in water T=0°C; 1 h;

1: 2.) HCl, sodium ethylate / 1.) acetonitrile, 90 deg C, 1 h; 2.) ethanol, 20 deg C, 5 h 2: 98 percent / 50percent H3PO4, NaNO2 / H2O / 1 h / 0 °C View Scheme

sodium hydride 1.) DMF, RT, 2.) DMF, RT, 0.5 h; Yield given. Multistep reaction. Yields of byproduct given;