合成路线1

Esterification of (R)-2-aminobutyric acid (X) with MeOH by means of SOCl2 and trimethyl orthoformate, followed by reductive alkylation of the resulting amino ester (XI) with acetone (XII) and NaBH(OAc)3, and treatment with HCl, gives methyl (R)-2-isopropylamino)butyrate hydrochloride (XIII). Basification of amino ester hydrochloride (XIII) with NaOH in cyclohexane/H2O, and subsequent condensation of the obtained free base with 2,4-dichloro-5-nitropyrimidine (XIV) in the presence of NaHCO3 in refluxing cyclohexane, yields the Npyrimidinyl amino ester (XV). Reductive cyclization of compound (XV) by catalytic hydrogenation in the presence of Pt/C and VO(acac)2 in THF gives pteridinone (XVI), which is finally methylated by heating with Me2CO3 in an autoclave in the presence of K2CO3 .