Allopurinol Related Compound F (25 mg) (ethyl-(E/Z)-3-(2-carbethoxy-2-cyanoethenyl)amino-1H-pyrazole-4-carboxylate);Allopurinol EP IMpurity F;Allopurinol IMpurity F;Allopurinol Related CoMpound F;ethyl-(E/Z)-5-(2-carbethoxy-2-cyanoethenyl)aMino-1H-pyrazole-4-carboxylate;(E/Z)-3-[(2-Cyano-3-ethoxy-3-oxo-1-propenyl)amino]-1H-Pyrazole-4-carboxylic Acid Ethyl Ester;Allopurinol IMpurity F (Mixture of Z and E IsoMers);(Ethyl-(E/Z)-3-(2-carbethoxy-2-cyanoethenyl)amino-1H-pyrazole-4-carboxylate)