1: N-benzenesulfonyl-2,4-dibromopyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: dimethyl amine in tetrahydrofuran; hexane T=-78 - 0°C; 1.5 h; Inert atmosphere; 3: With methyl chloroformate in tetrahydrofuran; hexane T=-78°C; 1 h; Inert atmosphere;

1: N-benzenesulfonyl-2,4-dibromopyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: formic acid ethyl ester in tetrahydrofuran; hexane T=-78°C; 1 h; Inert atmosphere; regioselective reaction;

1: N-benzenesulfonyl-2,4-dibromopyrrole With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: diethylamine in tetrahydrofuran; hexane T=-78 - 0°C; 1.5 h; Inert atmosphere; 3: With methyl chloroformate in tetrahydrofuran; hexane T=-78°C; 1 h; Inert atmosphere;