Synthesis of 2-amino-6-chloro- and 2,6-diammopunne 3-oxides
作者:Israel Scheinfeld、James C. Parham、George Bosworth Brown
DOI:10.1002/jhet.5570190551
日期:1982.9
N-Oxidation of 2-amino-6-chloropurine to the 3-oxide provided a convenient intermediate for the synthesis of 2-amino-6-substituted purine 3-oxides, including the previously unavailable 2,6-diaminopurine 3-oxide. Thiation of the 6-halogen was accompanied by reduction of the N-oxide. The properties of the 1- and 3-oxides of 2,6-diaminopurine are compared.
3-Amino-1-methyl-5H-pyrido [4, 3-b] indole (Trp-P-2) is a mutagen/carcinogen isolated from a pyrolysate of L-tryptophan. The active metabolite of Trp-P-2, 3-hydroxyamino-1-methyl-5H-pyrido [4, 3-b] indole (N-OH-Trp-P-2), was synthesized and the chemical reactions of N-OH-Trp-P-2 with deoxyribonucleic acid were investigated. The structure of the nucleic acid base covalently bound with Trp-P-2 was elucidated as 3-(C8-guanyl) amino-1-methyl-5H-pyrido [4, 3-b] indole (Gua-Trp-P-2) by comparison with a synthetic sample. The initial chemical events in carcinogenesis caused by Trp-P-2 were established.
Synthesis, Tautomerism and Calculations of Mesomeric Betaines of Guanine
作者:Andreas Schmidt、Nikoloz Kobakhidze
DOI:10.3987/com-02-9634
日期:——
Reaction of purine-N-oxide (4) with 4-(dimethylamino)pyridine and acetyl chloride, followed by the treatment with hydrochloric acid gave the purine-pyridinium salt (6) which was deprotonated to the mesomeric betaine (7). Depending on the reaction conditions, 4-methylpyridine and pyridine, respectively, converted the nucleoside (8) into the pyridinium salts (9) and (10), or into the mesomeric betaines (11) and (12). According to calculations, the conjugated tautomers (A-D) of betaine (7) are more stable than the cross-conjugated tautomer (7E).
SCHEINFELD, I.;PARHAM, J. C.;BROWN, G. B., J. HETEROCYCL. CHEM., 1982, 19, N 5, 1231-1233
作者:SCHEINFELD, I.、PARHAM, J. C.、BROWN, G. B.
DOI:——
日期:——
Synthesis and Base-Pairing of Self-Complementary Mesomeric Betaines of Guanine
作者:Andreas Schmidt、Nikoloz Kobakhidze
DOI:10.1246/cl.2002.222
日期:2002.2
Substitution of 8-H of guanine-N-oxide was accomplished by pyridine, 4-dimethylaminopyridine and acetylchloride, respectively, to give a cationic purine base after hydrolysis. Deprotonation formed mesomeric betaines of guanine. ESI mass spectrometry and 1H NMR revealed their self-complementarity. Base-pairing to cytosine was observed with a fully protected DNA model compound.
分别用吡啶、4-二甲氨基吡啶和乙酰氯取代鸟嘌呤-N-氧化物的8-H,水解后得到阳离子嘌呤碱。去质子化形成鸟嘌呤的中间体甜菜碱。ESI 质谱和 1 H NMR 揭示了它们的自互补性。使用完全保护的 DNA 模型化合物观察到与胞嘧啶的碱基配对。