Cyclization of 1-(4-nitrophenyl)acetone (I) with ethyl 2-cyanoacetate (II) by means of NH4OAc, HOAc, S and diethylamine gives 2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylic acid ethyl ester (III), which is cyclized with phenyl isocyanate (IV) in pyridine to yield the thieno[2,3-d]pyrimidinedione derivative (V). Alkylation of compound (V) with 2,6-difluorobenzyl chloride (VI) by means of K2CO3 and KI in DMF affords the adduct (VII), which is brominated with NBS and AIBN in chlorobenzene to provide the bromomethyl derivative (VIII). Reaction of compound (VIII) with N-benzyl-N-methylamine (IX) by means of DIEA in DMF gives the tertiary amine (X), which by reduction of the nitro group with H2 over Pd/C in ethyl ether/formic acid yields the primary amine (XI). Finally, this compound is treated with CDI, O-methylhydroxylamine (XII) and TEA in dichloromethane.