{TAIL ~ R1} is a hydrogen or halogen atom, or an aliphatic, carbocyclic, carbamoyl, sulfamoyl, carbonamido, sulfonamido, alkoxycarbonyl, {HEAD ~ alkyl} or arylketo, alkyl or arylsulfo, sulfo, hydroxy, acyl, nitro, cyano, amino, alkoxy, alkoxyalkyl, aryloxy, aryloxyalkyl, thioalkoxy, thioalkoxyalkyl, thioaryloxy, thioaryloxyalkyl or heterocyclic group 
{ TAIL ~ R1 } is a hydrogen or halogen atom , or an aliphatic , carbocyclic , carbamoyl , sulfamoyl , carbonamido , sulfonamido , alkoxycarbonyl , { HEAD ~ alkyl } or arylketo , alkyl or arylsulfo , sulfo , hydroxy , acyl , nitro , cyano , amino , alkoxy , alkoxyalkyl , aryloxy , aryloxyalkyl , thioalkoxy , thioalkoxyalkyl , thioaryloxy , thioaryloxyalkyl or heterocyclic group
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