Treatment of 3-methoxy-2-nitrobenzoic acid (I) with oxalyl chloride gave the corresponding acid chloride (II), which was then coupled with 2-amino-5-chloropyridine (III) to yield amide (IV). The reduction of the nitro group of (IV) using sodium hydrosulfite afforded aniline (V). Further chlorination of (V) with N-chlorosuccinimide furnished the 5-chloro derivative (VI).
Benzylic bromination of 2-(methoxycarbonyl)-3-chloro-4-methylthiophene (VII) gave rise to dibromide (VIII), which was further hydrolyzed to aldehyde (IX) using sodium acetate and acetic acid. Reduction of aldehyde (IX) with NaBH4 afforded alcohol (X). After basic hydrolysis of the methyl ester group of (X), the resulting hydroxy acid was treated with thionyl chloride to furnish (XI). Condensation of aniline (VI) with acid chloride (XI) gave amide (XII). Subsequent chloride displacement with methylamine yielded amine (XIII). This was then condensed with 2-bromoethyl isocyanate, producing the N-(2-bromoethyl)urea (XIV). Cyclization of bromo urea (XIV) upon treatment with triethylamine (1,2) or with other amines generated the title oxazoline derivative.