[CH:1]([NH:4][C:5]1[N:10]=[C:9]([C:11]([OH:13])=[O:12])[CH:8]=[C:7]([CH3:14])[N:6]=1)([CH3:3])[CH3:2].[CH2:15](O)[CH3:16]>OS(O)(=O)=O>[CH2:15]([O:12][C:11]([C:9]1[CH:8]=[C:7]([CH3:14])[N:6]=[C:5]([NH:4][CH:1]([CH3:3])[CH3:2])[N:10]=1)=[O:13])[CH3:16]To a solution of 2-isopropylamino-6-methyl-pyrimidine-4-carboxylic acid (1.27 g, 6.53 mmol) in ethanol (20 mL), concentrated H2SO4 (4 mL) is added. The reaction mixture is stirred at 80° C. for 18 h and is then evaporated. The residue is dissolved in EtOAc, washed with sat. aq. NaHCO3 and water, dried over MgSO4, filtered and evaporated. The crude compound is purified by CC on silica gel (eluting with Heptane/EtOAc 4:1) to give 2-isopropylamino-6-methyl-pyrimidine-4-carboxylic acid ethyl ester as a yellow oil (1.46 g); LC-MS: tR=0.97; [M+H]+=224.49.
Wird geladen…