1: 4-[2-(Piperidin-1-yl)ethoxy]benzoic acid hydrochloride With pyridine; thionyl chloride in dichloromethane 1 h; Heating / reflux; 2: 6-acetoxy-2-(4-acetoxyphenyl)benzo[b]thiophene in dichloromethane 3: With hydrogenchloride; sodium hydroxide; water; AlCl3, aluminium chloride more than 3 stages;

1: 6-methoxy-2-(4'-methoxyphenyl)-benzo[b]thiophene With pyridine; hydrogenchloride; tributyl-amine T=170 - 180°C; 2: With water in ethyl acetate 0.25 h; 3: acetic anhydride With triethylamine in ethyl acetate T=25 - 65°C; 1 h;

4-(N,N-dimethlyamino)pyridine; acetic anhydride in pyridine; water

pyridine; 4-(N,N-dimethlyamino)pyridine Ambient temperature;

1: 80.4 percent / KOH / ethanol; H2O; ethyl acetate / Ambient temperature 2: 69 percent / PPA / 1 h / 85 - 90 °C 3: 71 percent / pyridine hydrochloride / 6 h / 220 °C 4: 97 percent / 4-(dimethylamino)pyridine, pyridine / Ambient temperature View Scheme

1: 80.4 percent / KOH / ethanol; H2O; ethyl acetate / Ambient temperature 2: 69 percent / PPA / 1 h / 85 - 90 °C 3: 71 percent / pyridine hydrochloride / 6 h / 220 °C 4: 97 percent / 4-(dimethylamino)pyridine, pyridine / Ambient temperature View Scheme

1: 71 percent / pyridine hydrochloride / 6 h / 220 °C 2: 97 percent / 4-(dimethylamino)pyridine, pyridine / Ambient temperature View Scheme

1: 69 percent / PPA / 1 h / 85 - 90 °C 2: 71 percent / pyridine hydrochloride / 6 h / 220 °C 3: 97 percent / 4-(dimethylamino)pyridine, pyridine / Ambient temperature View Scheme

1: AlCl3 / 1,2-dichloro-ethane / 1 h 2: 5 N NaOH / methanol / 2 h / Ambient temperature View Scheme