1: (pyridin-3-yl)-carbamic acid tert-butyl ester With n-butyllithium; N,N,N',N,-tetramethylethylenediamine in diethyl ether; hexane T=-78 - -10°C; 2: carbon dioxide in tetrahydrofuran; diethyl ether; hexane T=-78°C; 0.5 h; 3: pH=~ 3; Acidic aqueous solution;

1.1: N-ethyl-N,N-diisopropylamine; diphenyl phosphoryl azide / toluene / 0.5 h / 20 °C 1.2: 6 h / 80 °C 2.1: n-butyllithium / hexane; tetrahydrofuran / -60 - 0 °C 2.2: 2 h / 20 °C / Cooling with acetone-dry ice 2.3: pH ~ 3 View Scheme

in tetrahydrofuran T=0 - 20°C;

1: With hydrogenchloride; water in methanol 2.5 h; Heating / reflux; 2: With sodium hydroxide; water T=20°C; pH=~ 14; 3: With hydrogenchloride; water pH=~ 3;