Compounds of Formula I in which R1 includes a urea moiety can be synthesized from primary amines in a variety of ways using phosgene, triphosgene, carbonyldiimidazole, and others as coupling reagents. One preferred way includes the use of the reagent phenyl carbamate (Young, R. J. et al, Bioorg. Med. Chem. Lett. 2006, 16, 5953-7). Starting material 1-(2-aminoethyl)-3-methyl-7-(3-(trifluoromethyl)benzyl-amino)quinoxalin-2(1H)-one (50 mg) was heated to reflux in THF for 2 h in the presence of N-methyl morpholine (0.16 mmol) and phenyl carbamate (0.16 mmol). The reaction mixture was concentrated and purified by chromatography using 6% MeOH in dichloromethane as eluent. Product 1-(2-(3-methyl-2-oxo-7-(3-(trifluoromethyl)benzyl-amino)quinoxalin-1(2H)-yl)ethyl)urea was isolated as off-white solid.
