Pyridopyrimidinone (I) was condensed with triazole (II) in the presence of 4-chlorophenyl dichlorophosphate and pyridine to afford (III). Further reaction of (III) with ammonia in dioxan gave amino compound (IV), which was submitted to a Heck reaction with 4-iodobenzoyl-L-glutamic acid diethyl ester (V) in the presence of palladium catalyst and CuI to provide the disubstituted acetylene (VI). Hydrogenation of both acetylene group and pyridine ring of (VI) over Pd/C gave intermediate (VII). The amide and ester groups of (VII) were finally hydrolyzed with 1 N NaOH to furnish the title compound.

Pyridopyrimidinone (I) was condensed with triazole (II) in the presence of 4-chlorophenyl dichlorophosphate and pyridine to afford (III). Further reaction of (III) with ammonia in dioxan gave amino compound (IV), which was submitted to a Heck reaction with N-(2-bromothien-5-yl)-L-glutamic acid diethyl ester (V) in the presence of palladium catalyst and CuI to provide the disubstituted acetylene (VI). Hydrogenation of both acetylene group and pyridine ring of (VI) over Pd/C gave intermediate (VII). The amide and ester groups of (VII) were finally hydrolyzed with 1 N NaOH to furnish the title compound.

Pyridopyrimidinone (I) was condensed with triazole (II) in the presence of 4-chlorophenyl dichlorophosphate and pyridine to afford (III). Further reaction of (III) with ammonia in dioxan gave amino compound (IV), which was submitted to a Heck reaction with N-(2-bromofuran-5-yl)-L-glutamic acid diethyl ester (V) in the presence of palladium catalyst and CuI to provide the disubstituted acetylene (VI). Hydrogenation of both acetylene group and pyridine ring of (VI) over Pd/C gave intermediate (VII). The amide and ester groups of (VII) were finally hydrolyzed with 1 N NaOH to furnish the title compound.