1.1: ammonia / methanol; acetone / -10 °C / |Inert atmosphere 2.1: Na2WO4·2H2O / methanol; water / 47 h / 10 - 50 °C / |Inert atmosphere 3.1: sodium tetrahydroborate / water; tetrahydrofuran / 2 h / 15 °C / |Inert atmosphere 3.2: 2 h / 40 °C 4.1: methanesulfonic acid / water; acetonitrile / 19 h / 10 - 87 °C / |Inert atmosphere; |Reflux 4.2: 4 h / 7 - 40 °C / pH 7.3 View Scheme