合成路线1

The reaction of L-phenylalanine (I) with benzyl bromide and K2CO3 in hot ethanol/water gives N,N,O-tribenzyl derivative (II), which is condensed with acetonitrile (III) by means of NaNH2 in THF yielding the pentanenitrile (IV). The reaction of nitrile (IV) with benzylmagnesium chloride (V) in THF affords the diphenylhexenone (VI), which is reduced with NaBH4 in THF to give the diphenylhexanol (VII). The protection of the amino group of (VII) with Boc2O and K2CO3 in methyl tert-butyl ether yields the carbamate (VIII), which is debenzylated with ammonium formate over Pd/C in methanol affording the amino compound (IX). The condensation of (IX) with 2-(2,6-dimethylphenoxy)acetic acid (X) by means of EDAC in DMF provides the corresponding amide (XI), which is deprotected at the carbamate group with TFA in dichloromethane to give (XII) with a free amino group. Finally, this compound is condensed with 3-methyl 2(S)-(2-oxoperhydropyrimidin-1-yl)butyric acid (XIII) by means of EDAC in DMF or SOCl2 and imidazole to furnish the target compound. The intermediate 2-(2,6-dimethylphenoxy)acetic acid (X) has been obtained by condensation of 2,6-dimethylphenol (XIV) with ethyl 2-bromoacetate (XV) by means of Cs2CO3 in refluxing dioxane to give the acetate ester (XVI), which is hydrolyzed with LiOH ethanol/water to afford the target intermediate (X).