Purines, mercapto-, tautomerism

Purine, 6-iodo-alkylation, 5, 530 synthesis, 5, 563, 597 Purine, 6-iodo-9- -D-(2,3,5-tri-0-acetyl)ribofuranosyl-synthesis, 5, 598 Purine, 9-isopropyl-deuterium-hydrogen exchange, 5, 527 Purine, 9-(2,3-0-isopropylidene-/3-D-ribofuranosyl)-6-methoxy-synthesis, 5, 584 Purine, 6-mercapto-biological activity, 5, 604 metabolism, 1, 237 as pharmaceutical, 1, 159 tautomerism, 5, 509 Purine, 2-methoxy-synthesis, 5, 596 Purine, 6-methoxy-irradiation, 5, 543 riboside... 

Lactam-lactim interconversion and the tautomerism between the thione and thiol forms, which could occur in the pyrimidine portion of hypoxanthine and 6-mercapto-purine, respectively, have been investigated by using the chemical shift of the C-6 carbon. The relative position of the C-6 resonance made it possible to calculate the amount of N -H tautomer by using Eq. (3)... 

Method D is illustrated in Scheme 28 The sodium salt of 8-mercapto-xanthine reacted with chloroacetone and the resulting tautomeric intermediates were dehydrated with ethanolic hydrogen chloride to a tricyclic 6-methyl-thiazolo[2,3-/]-purine-2,4(1/7,3//)-dione 104. 

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