合成路线1

The formylation of 3,5-dichloropyridine (I) with methyl formate by means of lithium diisopropylamide (LDA) in THF gives 3,5-dichloropyridine-4-carbaldehyde (II), which is condensed with p-thiocresol (III) by means of K2CO3 in DMF (or t-BuOK in THF) yielding 3-chloro-5-(4-methylphenylsulfanyl)pyridine-4-carbaldehyde (IV). The cyclization of (IV) with methyl thioglycolate (V) by means of K2CO3 in DMF affords 4-(4-methylphenylsulfanyl)thieno[2,3-c]pyridine-2-carboxylic acid methyl ester (VI), which is finally condensed with 2,3-dihydroxypropylamine (VII) by means of NaH in DMF to obtain the target amide. Alternatively, The hydrolysis of the methyl ester (VI) with LiOH in hot isopropanol/water gives the corresponding free acid (VIII), which is treated with N-hydroxysuccinimide (IX) and DCC in dichloromethane to obtain the activated ester (X). Finally, this compound is treated with 2,3-dihydroxypropylamine (VII) in dioxane/methanol to afford the target amide. The activation of the acid (VIII) can also be performed with oxalyl chloride or EDC and HOBT.