5-Deshydroxy-5-formyl N,N'-Trityl Losartan Impurity B; 2-[1-[[2-Butyl-4-chloro-1-[[2α-[2-(triphenylmethyl)-2H-tetrazol-5-yl][1,1α-biphenyl]-4-yl]methyl]-1H-imidazol-5-yl]hydroxymethyl]butyl]-4-chloro-1-[[2α-[2-(triphenylmethyl)-2H-tetrazol-5-yl][1,1α-biphenyl]-4-yl]methyl]-1H-imidazole-5-carboxaldehyde