The intermediate carbamate (V) has been obtained as follows. The reaction of 4-bromo-3-methoxynitrobenzene (I) with CuCN in NMP at 150 C gives 2-methoxy-4-nitrobenzonitrile (II), which is reduced with H2 over Pd/C in ethyl acetate to yield 4-amino-2-methoxybenzonitrile (III). Finally, this compound is condensed with phenyl carbamate (IV) by means of NaHCO3 in ethyl acetate to afford the desired carbamate intermediate (V).

The reduction of 3-nitroacetophenone (VI) by means of NaBH4 in ethanol gives 1-(3-nitrophenyl)ethanol (VII), which is treated with DPPA and DBU in hot toluene to yield the azido derivative (VIII). The reduction of (VIII) with PPh3 in THF/water affords 1-(3-nitrophenyl)ethylamine (IX) as a racemic mixture that is submitted to optical resolution with L-(+)-tartaric acid to provide the desired (S)-isomer (X). The reduction of the nitro group of (X) by means of H2 over Pd/C in methanol gives 1(S)-(3-aminophenyl)ethylamine (XI), which is condensed with 2(R)-hydroxypentanenitrile (XII) and CDI to yield the carbamate (XIII). Finally, this compound is condensed with intermediate carbamate (V) by means of TEA in hot ethyl acetate to afford the target urea.