a nitrobenzoyl chloride such as m nitrobenzoyl chloride or 3 nitro p toluoyl chloride for 1 5 36 hours after neutralization the solution is diluted with absolute ethanol to provide the corresponding nitro substituted phenylenecarbonyl and sulfonyl imino substituted phenylenesulfonylimino naphthalenetrisulfonic acid trialkali metal salt the novel intermediate amine compounds of the invention are then obtained by hydrogenation of the above nitro compounds using 10 palladium carbon catalyst in water as previously described filtration and evaporation of the filtrate produces a residue which is dissolved in water and precipitated with absolute ethanol to provide the desired product the novel ureylene compounds of the invention which are active complement inhibitors are then provided by treatment of the above intermediate amine compounds with phosgene in aqueous media made alkaline with alkali metal carbonate or pyridine neutralization and precipitation from aqueous solution with alcohol this invention is concerned with a method of inhibiting the complement system in a body fluid such as blood serum which comprises subjecting body fluid complement to the action of an effective complement inhibiting amount of a compound encompassed within the formulae hereinabove the method of use aspect of this invention is also concerned with a method of inhibiting the complement system in a warm blooded animal which comprises administering to said animal an effective complement inhibiting amount of a compound encompassed within the formulae hereinabove body fluid can include blood plasma serum synovial fluid cerebrospinal fluid or pathological accumulations of fluid such as pleural effusion etc compounds of the present invention find.