dicyclohexyl-carbodiimide in ethyl acetate Ambient temperature;

1: 82 percent / HOBt hydrate, pentachlorophenol, triethylamine / dimethylformamide / 19 h / Ambient temperature 2: 94 percent / 7n HCl / methanol / 0.08 h / Ambient temperature 3: 1) 9.2n HCl, isoamyl nitrite, 2) Et3N / 1) DMF, THF, 30 min, -47 deg C, 2) 48h, -5 deg C 4: 99percent hydrazine hydrate / 1) -20 deg C, Et3N, THF, 2) 48h to -5deg C, DMF 3) 20h to -5deg C 5: 1) 6.1n HCl, isoamyl nitrite, 2) triethylamine / 1) -30deg C, THF, 30 min; 2) -45deg C, DMF, 15h between -5deg C to 0deg C View Scheme

1: 1.) 1 N NaOH, dioxane, 2.) ether 3: 58 percent / 2 N hydrogen chloride / acetic acid View Scheme