1.1: morpholine; sulfur / 12 h / 110 °C 1.2: 8 h / Reflux 2.1: sulfuric acid / 2 h / 50 °C 3.1: sodium t-butanolate / tert-butyl methyl ether / 2 h / 5 - 20 °C 4.1: (S)-pyrophosphoric acid / water / 2 h / 0 - 60 °C 5.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / 20 - 35 °C 6.1: hydrogen / Ni-Raney / tetrahydrofuran / 48 h / 20 °C / 2585.81 - 3102.97 Torr 7.1: ethyl acetate / 96 h / 25 °C 8.1: boron trifluoride diethyl etherate; triethylsilane / 24 h / 105 °C 9.1: sodium hydroxide / dichloromethane; water / pH > 10 9.2: 2 h / 60 °C View Scheme

1: With morpholine; sulfur T=110°C; 12 h; 2: With hydrogenchloride; acetic acid in water 8 h; Reflux;

1.1: morpholine; sulfur / 12 h / 110 °C 1.2: 8 h / Reflux 2.1: sulfuric acid / 2 h / 50 °C 3.1: sodium t-butanolate / tert-butyl methyl ether / 2 h / 5 - 20 °C 4.1: (S)-pyrophosphoric acid / water / 2 h / 0 - 60 °C 5.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / 20 - 35 °C 6.1: hydrogen / Ni-Raney / tetrahydrofuran / 48 h / 20 °C / 2585.81 - 3102.97 Torr 7.1: ethyl acetate / 96 h / 25 °C 8.1: lithium aluminium tetrahydride; AlCl3, aluminium chloride / tetrahydrofuran / 0 - 20 °C 8.2: 0.33 h / 2 °C View Scheme

copper; potassium carbonate 10 h; Heating;

potassium hydroxide; sodium hydroxide in ethanol

copper; phenol T=120 - 125°C; 24 h;

hydrogenchloride; sodium hydroxide in benzene

sulfur 24 h; Heating;

sulfur 12 h; Heating; Title compound not separated from byproducts;

1: 1.) morpholine, sulfur, 2.) glacial acetic acid, conc. aq. HCl / 1.) reflux, 12 h, 2.) reflux, 8 h 2: 61 percent / polyphosphoric acid / 100 - 105 °C View Scheme