Reaction of 2,5-dibromopyridine (I) with morpholine (II) yields 5-bromo-2-(4-morpholinyl)pyridine (III). Palladium-catalyzed coupling of (III) with trimethylsilyl acetylene (IV) leads to the ethynylpyridine (V)

Iodination of 5-amino-4,6-dichloropyrimidine (VI) by means of NaI in concentrated HI affords the diiodopyridine (VII). Sequential alkylation of aminopyrimidine (VII) with 2-chlorobenzyl bromide (VIII) to produce (IX), and further N-methylation with iodomethane and NaH, lead to the tertiary amine (X). Ammonolysis of the diiodopyrimidine (X) with ethanolic ammonia in a sealed tube at 80 C yields amine (XI). Finally, Sonogashira coupling between acetylene (V) and iodopyrimidine (XI) in the presence of Pd(PPh3)2Cl2 and CuI furnishes the target diaryl acetylene