1.1: sulfuric acid / acetic acid / 0.5 h / 20 °C 2.1: methanol; sodium tetrahydroborate / 0.5 h 3.1: sulfuric acid / 3 h / |Reflux 4.1: ethanethiol; n-butyllithium / N,N,N',N',N'',N''-hexamethylphosphoric triamide / 2 h / 0 - 70 °C / |Inert atmosphere 5.1: sodium hydride / N,N-dimethyl-formamide / 0.17 h / 0 °C 5.2: 2 h / 0 - 20 °C 6.1: ethanethiol; n-butyllithium / N,N,N',N',N'',N''-hexamethylphosphoric triamide / 2 h / 0 - 70 °C / |Inert atmosphere View Scheme