合成路线1

Catalytic hydrogenation of 2-bromo-4-nitrotoluene (I) over Raney-Ni provided aniline (II). Reaction of (II) with chloral hydrate and hydroxylamine gave rise to the isonitrosoacetanilide (III), which was subsequently cyclized to the isatin (IV) by heating in concentrated H2SO4. Oxidative cleavage of isatin (IV) produced the anthranilic acid (V). This was converted to the benzoxazinone (VI) upon refluxing with acetic anhydride. Ring opening of benzoxazinone (VI) with MeOH, followed by acidic hydrolysis of the acetamide function, yielded the anthranilate ester (VII). The quinazoline derivative (VIII) was then obtained by treatment of anthranilate (VII) with chloroformamidine hydrochloride in refluxing diglyme. Finally, displacement of the bromide group of (VIII) with the sodium thiolate of 4-mercaptopyridine (IX) under Ullmann conditions afforded the title pyridyl sulfide.

合成路线2

Condensation of 2,6-diamino-4-hydroxypyrimidine (I) with chloroacetone (II) produced a mixture of pyrrolopyrimidine (III) and furopyrimidine (IV). After treatment of this mixture with pivalic anhydride, the insoluble pivaloyl amide of pyrrolopyrimidine (V) was separated from the soluble dipivaloyl furopyrimidine with boiling EtOAc. Subsequent Mannich reaction of (V) with dimethylamine and formaldehyde afforded the (dimethylamino)methyl derivative (VI). The dimethylamino group of (VI) was then displaced with 4-mercaptopyridine (VII) to give thioether (VIII). Finally, the pivaloyl amide group of (VIII) was hydrolyzed with NaOH to yield the target compound.

合成路线3