7-[N2,N3-Bis(benzyloxycarbonyl)guanidino]-8-methylquinoline. To a pale yellow solution of 500 mg of 7-amino-8-methylquinoline in 20 mL of tetrahydrofuran are added 1.18 g of ethyl N,N-bis(benzyloxy-carbonyl)pseudothiourea and 1.01 g of mercuric acetate and the mixture is stirred at room temperature for 1 hour. The suspension is diluted with ethyl acetate and the organic layer is washed with water followed by brine. The aqueous layers are extracted with ethyl acetate; the combined organic layers are dried over magnesium sulfate, filtered and rotary evaporated. The residue is purified by flash column chromatography on silica gel, eluting with 50% ethyl acetate/hexanes and recrystallization from hexanes/methylene chloride to provide 1.257 g of 7-[N2,N3-bis(benzyloxycarbonyl)guanidino]-8-ethylquinoline as a white solid.
