“ When heated with pyridine to 140° C., it is converted into allomucic acid. When digested with fuming hydrochloric acid for some time it is converted into αα′ furfurane dicarboxylic acid (see Furfurane) ; while on heating with barium sulphide it is transformed into α—thiophene carboxylic acid (see Thiophene) . The ammonium salt yields on dry distillation carbon dioxide, ammonia, pyrrol and other substances. The acid when fused with caustic alkalies yields oxalic acid. ”