triethylamine in methanol 12 h; Ambient temperature;

1: 70 percent / pyridine / 5 h / Ambient temperature 2: 59 percent / 2.5N NH3 / methanol / 6 h 3: 1) Et3N, chloroformic acid isobutylester / 1) THF, -15 deg C, 8 min, 2) DMF, RT, 15 min View Scheme

1: 59 percent / 2.5N NH3 / methanol / 6 h 2: 1) Et3N, chloroformic acid isobutylester / 1) THF, -15 deg C, 8 min, 2) DMF, RT, 15 min View Scheme

triethylamine; isobutyl chloroformate 1) THF, -15 deg C, 8 min, 2) DMF, RT, 15 min; Yield given. Multistep reaction;