1: T=80°C; 1 h; 2: With toluene-4-sulfonic acid in toluene T=100°C; 3 h;

1.1: 4-(N,N-dimethlyamino)pyridine; copper diacetate / dichloromethane / 12 h / 20 °C 2.1: nitric acid; acetic acid / 10 - 40 °C 3.1: zinc; acetic acid / dichloromethane; ethanol / 0.5 h / 20 °C 4.1: 1 h / 80 °C 4.2: pH 9 - 10 4.3: 3 h / 100 °C View Scheme

1.1: zinc; acetic acid / dichloromethane; ethanol / 0.5 h / 20 °C 2.1: 1 h / 80 °C 2.2: pH 9 - 10 2.3: 3 h / 100 °C View Scheme

1.1: nitric acid; acetic acid / 10 - 40 °C 2.1: zinc; acetic acid / dichloromethane; ethanol / 0.5 h / 20 °C 3.1: 1 h / 80 °C 3.2: pH 9 - 10 3.3: 3 h / 100 °C View Scheme

copper(I) oxide; ammonia in ethylene glycol T=70°C; 3 h;