合成路线1

1) The condensation of 2,4,5,6-tetraaminopyrimidine sulfate (I) with dihydroxyacetone dimer (II) in the presence of cysteine and O2 furnished 2,4-diamino-6-(hydroxymethyl)pteridine (III). Subsequent reaction of (III) with dibromotriphenylphosphorane in dimethylacetamide afforded bromide (IV) which, without isolation, was condensed with 4-aminobenzoic acid (V) in the presence of BaO to give 4-amino-4-deoxypteroic acid (VI). Formylation of (VI) with acetic-formic anhydride yielded formamide (VII), and subsequent activation as the 4-nitrophenyl ester (IX) was carried out upon reaction with bis(4-nitrophenyl)carbonate (VIII). Then Nd-Boc-L-ornithine, after conversion to the corresponding Na,O-bis(trimethylsilyl) derivative (X) by treatment with ClSiMe3 and triethylamine, was condensed with active ester (IX) to furnish amide (XI). Subsequent deprotection of the Boc group of (XI) with cold trifluoroacetic acid provided (XII), which was then condensed with phthalic anhydride (XIII) in the presence of triethylamine in N-methylpyrrolidinone, yielding the hemiphthaloyl amide (XIV). Finally, the formamide function was hydrolyzed with aqueous NaOH at r.t. to provide the target compound, after chromatographic separation of some phthaloyl-hydrolyzed byproduct.