合成路线1

Condensation of 2-amino-6-bromopyridine (I) with ethoxycarbonyl isothiocyanate (II) in CH2Cl2 gives 1-(6-bromopyridin-2-yl)-3-(ethoxycarbonyl) thiourea (III), which by cyclization with hydroxylamine hydrochloride (IV) in the presence of DIEA in EtOH/MeOH yields 2-amino-5-bromo[1,2,4]triazolo[1,5-a]pyridine (V). N-Acylation of amine (V) with cyclopropanecarbonyl chloride (VI) using Et3N in acetonitrile, and subsequent treatment with methanolic ammonia, results in the carboxamide (VII) . Suzuki coupling of compound (VII) with 4-(hydroxymethyl)phenylboronic acid (VIII) in the presence of PdCl2(dppf) and K2CO3 in dioxane/H2O at 90 °C, followed by bromination with PBr3 in CHCl3, affords the benzyl bromide intermediate (IX), which is finally condensed with thiomorpholine-1,1-dioxide (X) using DIEA in CH2Cl2/MeOH .
Alternatively, condensation of (4-bromomethylphenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (XI) with thiomorpholine 1,1-dioxide (X) by means of DIEA in CH2Cl2/MeOH gives intermediate (XII), which finally undergoes Suzuki coupling with aryl bromide (VII) in the presence of PdCl2(dppf) and K2CO3 in dioxane/H2O at 90 °C .