R3 is hydrogen, lower alkyl, {HEAD ~ lower alkyl} substituted with a halogen, alkoxy, amino, carboxylic acid, ester or amide group, benzyl, {TAIL ~ phenyl}, nitro, trifluoromethyl, a cycloalkyl group containing 3 to 6 carbons, halogen, or part of an alkylene bridge to form a quaternary salt with the double bonded imidazole nitrogen, substituted phenyl or substituted benzyl, for which the substituents are the same as those set forth for R1 and R2 substituted benzyl or phenyl 
R3 is hydrogen , lower alkyl , { HEAD ~ lower alkyl } substituted with a halogen , alkoxy , amino , carboxylic acid , ester or amide group , benzyl , { TAIL ~ phenyl } , nitro , trifluoromethyl , a cycloalkyl group containing 3 to 6 carbons , halogen , or part of an alkylene bridge to form a quaternary salt with the double bonded imidazole nitrogen , substituted phenyl or substituted benzyl , for which the substituents are the same as those set forth for R1 and R2 substituted benzyl or phenyl
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