合成路线1

3-Acetylbenzonitrile (I) was protected as the ethylene ketal (II) employing ethylene glycol and boron trifluoride etherate. Reduction of the cyano group of (II) with LiAlH4 gave amine (III), and further ketal hydrolysis provided 3-acetylbenzylamine (IV). This was acetylated using acetyl chloride and Et3N to yield the intermediate amide (V). Alternatively, intermediate (V) was obtained by addition of methylmagnesium bromide to N-(3-cyanobenzyl)acetamide (VI). Bromination of (V) in dioxan furnished the bromoacetophenone (VII). This was cyclized to the aminothiazole (IX) by treatment with thiourea (VIII) in refluxing ethanol. Condensation of (IX) with benzoyl isothiocyanate (X) provided the benzoyl thiourea (XI). After selective hydrolysis of the benzoyl group of (XI) with NaOH in MeOH-H2O at 60 C, the resulting thiourea (XII) was methylated with iodomethane yielding S-methylisothiourea (XIII). Finally, displacement of the methylthio group with 2-methoxyetylamine (XIV) furnished the title guanidinothiazole.