Electronic Aspects of Purine Tautomerism

摘要: Publisher Summary This chapter focuses on the various tautomeric forms of fundamental purines. The principal types transformation liable to occur in most significant group purines are prototropic tautomerism, amine-imine and lactam-lactim tautomerism. tautomerisms may be coupled with shift “imidazole proton” purine skeleton. In polysubstituted derivatives, such as 8-azaguanine, all different can intermingled. A number some have been studied quantum mechanically help standard, semi empirical Huckel approximation molecular orbital method. These studies enabled determination a electronic differences among tautomers. Although molecule is generally represented form N(9)H which hydrogen atom attached N-9, naturally considered proton other nitrogens molecule, yielding tautomers N(7)H, N(3)H, N(1)H. majority biological exist essentially derivatives tautomer, crystalline itself, consists long chains these molecules linked together by single bonds, involves N(7)H tautomer.