Penicillin V Impurity 13

2- (carboxy (2-phenoxyacetamido) methyl) -3- (2- (4-carboxy-3- (2- (4-carboxy-5,5-dimethylthiazolidin-2-yl) -2- (2-phenoxyacetamido) acetyl) -5,5-dimethylthiazolidin-2-yl) -2- (2-phenoxyacetamido) acetyl) -5,5-dimethylthiazolidine-4-carboxylic acid