715 mg of 1,1-diethyl-3-(2,6-dimethyl-13-hydroxymethyl- 8alpha-ergolinyl)-urea (1.5 mmol) is dissolved in 10 ml of pyridine and mixed with 2 ml of trimethylacetyl chloride. Ice is added after 30 minutes of stirring at room temperature, it is stirred for another 30 minutes, made alkaline with ammonia and the mixture is cooled in an ice bath. The precipitated crystals are suctioned off, yield 785 mg, [α]D =-2° (0.5% in chloroform). The mother liquor is extracted with dichloromethane, dried and concentrated by evaporation. Both fractions are dissolved together in 6 ml of tetrahydrofuran and the solution is instilled in 50 ml of condensed, anhydrous ammonia. Then, it is mixed with 160 mg of lithium and the blue solution is stirred for 30 minutes at -40° C. Solid ammonium chloride, until decolorization, and 5 ml water are added in succession, the ammonia is evaporated and it is diluted with 80 ml of water. After 30 minutes of stirring in an ice bath, the precipitated crystals are suctioned off and dried in a vacuum, yield 643 mg (94% of theory), [α]D =+3° (0.5% in chloroform).
