. Cellular toxins; or, The chemical factors in the causation of disease. Poisons; Pathology; Bacteria. 338 CHEMISTRY OF THE LEUCOMAINS. that the xanthin bases possessed essentially the same structure as uric acid. This fact was rendered still more evident when hydroxy-caf- fein not only was recognized to be a tri-methyl uric acid, but on treatment with methyl iodid was shown to form the tetra-methyl uric acid. Fischer therefore abandoned the formulae of caffein and xanthin which he proposed in 1883 and accepted those which Medi- cus had previously suggested. The formula which Medicus suggested
. Cellular toxins; or, The chemical factors in the causation of disease. Poisons; Pathology; Bacteria. 338 CHEMISTRY OF THE LEUCOMAINS. that the xanthin bases possessed essentially the same structure as uric acid. This fact was rendered still more evident when hydroxy-caf- fein not only was recognized to be a tri-methyl uric acid, but on treatment with methyl iodid was shown to form the tetra-methyl uric acid. Fischer therefore abandoned the formulae of caffein and xanthin which he proposed in 1883 and accepted those which Medi- cus had previously suggested. The formula which Medicus suggested and which shows best the various decompositions of uric acid is that given below (1). The tauto- meric form (2) has a great deal in its favor, but is not used. Similar tautomeric formulae can be deduced for purin, trichlor purin, adenin and other bases. (1) HN—CO OC HN—C—NH —NH O HO. (2) = C. N—C—N •NH OH Ukic Acid. The group C^N^ in the above formulae is designated as the purin nucleus and from it purin itself, CgH^N^, is easily derived. The nomenclature of purin bodies is based upon the order of substitution in the purin nucleus, C^N^. Nine positions are possible as shown in the second formula below : :h N=CI HC C—NH CH II N—C—N N3-C,- Uric acid becomes 2-6-8 tri-oxypurin. By the introduction of a single methyl group into uric acid a methyl uric acid results. On examining the formula of uric acid it will be seen that theoretically four methyl uric acids are possible. Strange to say there are present six known mono-methyl uric acids; in other words there are two more than are theoretically possible. OC C—NH HN—CO OC C— o NH !0 HN—CO C—N- OC CH3 HN—CO OC C—NH HN—C—NH CH3N—G-NH HN—C—NH HN—C— 1-Methyl Uric Acid. 3-Methyl Uric Acid. 7-Methtl Uric Acid. 9-Methyl Uric Acid. By substituting two methyl groups into uric acid a di-methyl uric acid results. Six di-methyl uric acids are possible and all are known,
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectpoisons, bookyear1902
