1: 85 percent / Et3N / butan-1-ol / 40 h / 120 °C 2: 2.) HCl / 1.) a) RT, 1 h, b) 80 to 90 deg C, 40 h, 2.) MeOH, RT, 30 min 3: 65 percent / NH3 / methanol / 48 h / 140 °C View Scheme

1: ethanol / 20 °C / Reflux; Resolution of racemate 2: potassium carbonate / water; isobutyl methylketone 3: potassium tert-butylate 4: hydrogen / palladium on activated charcoal / ethanol View Scheme

1: ethanol / 20 °C / Reflux; Resolution of racemate 2: potassium carbonate / water; isobutyl methylketone View Scheme