[Cl:1][C:2]1[N:7]=[C:6]([C:8]([OH:10])=O)[CH:5]=[N:4][CH:3]=1.C[N:12]1C(=O)CCC1.ClC(OCC(C)C)=O.[NH4+].[OH-]>CN(C=O)C>[Cl:1][C:2]1[N:7]=[C:6]([C:8]([NH2:12])=[O:10])[CH:5]=[N:4][CH:3]=1A solution of 6-chloro-pyrazine carboxylic acid (2.00 g, 12.62 mmol) in DMF (7 mL) was cooled to −40° C. NMP (2.77 mL, 25.23 mmol) and isobutyl chloroformate 3.27 mL, 25.23 mmol) were added. The temperature was allowed to increase to −20° C. during 20 min and then NH4OH was added. A precipitate was rapidly formed and after 15 min it was filtered off and washed with water. Crystallization from EtOH gave the title compound (670 mg, 34%) as light-brown needles.
Wird geladen…