1: acetonitrile With n-butyllithium in tetrahydrofuran T=-78°C; 0.583333 h; 2: methyl 4-ethoxy-5-methoxy-2-(dimethylaminomethyleneamino)benzoate in tetrahydrofuran T=-78°C; 0.833333 h;

1: acetonitrile With n-butyllithium in tetrahydrofuran; hexane T=-78°C; Metallation; 0.333333 h; 2: methyl 4-ethoxy-5-methoxy-2-(dimethylaminomethyleneamino)benzoate in tetrahydrofuran; hexane T=-78°C; Addition; 1 h; 3: With acetic acid in tetrahydrofuran; hexane T=-78 - 25°C; Cyclization; Further stages.;

1.1: 82 percent / K2CO3 / dimethylformamide / 2 h / 100 °C 2.1: HNO3; glacial AcOH / 1 h / 50 - 60 °C 3.1: Fe; aq. NH4Cl / methanol / 19 h / Heating 4.1: dimethylformamide / 2.3 h / Heating 5.1: n-BuLi / hexane; tetrahydrofuran / 0.33 h / -78 °C 5.2: hexane; tetrahydrofuran / 1 h / -78 °C 5.3: glacial acetic acid / tetrahydrofuran; hexane / -78 - 25 °C View Scheme

1.1: HNO3; glacial AcOH / 1 h / 50 - 60 °C 2.1: Fe; aq. NH4Cl / methanol / 19 h / Heating 3.1: dimethylformamide / 2.3 h / Heating 4.1: n-BuLi / hexane; tetrahydrofuran / 0.33 h / -78 °C 4.2: hexane; tetrahydrofuran / 1 h / -78 °C 4.3: glacial acetic acid / tetrahydrofuran; hexane / -78 - 25 °C View Scheme

1.1: dimethylformamide / 2.3 h / Heating 2.1: n-BuLi / hexane; tetrahydrofuran / 0.33 h / -78 °C 2.2: hexane; tetrahydrofuran / 1 h / -78 °C 2.3: glacial acetic acid / tetrahydrofuran; hexane / -78 - 25 °C View Scheme

1.1: Fe; aq. NH4Cl / methanol / 19 h / Heating 2.1: dimethylformamide / 2.3 h / Heating 3.1: n-BuLi / hexane; tetrahydrofuran / 0.33 h / -78 °C 3.2: hexane; tetrahydrofuran / 1 h / -78 °C 3.3: glacial acetic acid / tetrahydrofuran; hexane / -78 - 25 °C View Scheme

oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane Chlorination; 48 h;

in dichloromethane; sodium hydrogencarbonate; N,N-dimethyl-formamide