4-氮杂环丁烷。2 †。于吡嗪并[2,3- e ]-作为-三嗪环系统共价添加方式的光谱,色谱和X射线晶体学研究
摘要:
未知吡嗪并[2,3- e ]-为-三嗪环系统的第一个例子,即6,7-二羟基-5,6,7,8-四氢吡嗪并[2,3 - e ]-为-通过将选定的5,6-二氨基-作为-三嗪与40%的乙二醛水溶液闭环来制备三嗪。这些4-氮杂环丁烷在C(7)位置经历与醇的新型交换过程。当溶于醇中并在室温下搅拌时,形成并分离出7-烷氧基,6-羟基类似物。实际上,在闭环过程中,如果将醇用作溶剂,则仅获得后者的化合物。最初,邻位-二氨基-环化为带有乙二醛的β-三嗪以立体选择性方式进行,同时产生顺式和反式加合物。单晶X射线衍射研究已确定主要和最稳定的加合物是反式(R,R或S,S)异构体。光谱法(nmr)证实了顺式加合物的中间体,但是由于上述交换过程,仅反式异构体被分离出来。这些σ加合物的交换位点已严格确定为C(7)。提出了发生这种交换过程的可能的反应机理。
6-Azapurines. Part 1. Determination of the tautomeric populations in 3-methylthioimidazo[4,5-e]-as-triazine by 13C and 15N nuclear magnetic resonance spectroscopy
作者:Jacques Riand、Marie-Th�r�se Chenon、Cherng-Chyi Tzeng、Raymond P. Panzica
DOI:10.1039/p29860000931
日期:——
3-Methylthioimidazo[4,5-e]-as-triazine (1) was synthesized via ring closure of 5,6-diamino-3-methylthio-as-triazine. By using carbon-13 and nitrogen-15 chemical shifts and three-bond 13C–1H spin–spin coupling constants, the prototropic tautomerism in the imidazole moiety of this 6-azapurine was investigated. The data from these spectral techniques indicated that the 5H-tautomeric form predominates
3-甲硫基咪唑并[4,5- ë ] -如三嗪(1)合成通过5,6-二氨基-3-甲硫基的环闭合作为三嗪。通过使用碳13和氮15的化学位移和三键13 C - 1 H自旋-自旋偶合常数,研究了该6-氮杂嘌呤咪唑部分的质子互变异构。来自这些光谱技术的数据表明5H-互变异构形式占主导(69%)。提供了对这三种方法的关键评估。
Tzeng, Cherng Chyi; Paznica, Raymond P., Journal of Heterocyclic Chemistry, 1983, vol. 20, p. 1123 - 1125
作者:Tzeng, Cherng Chyi、Paznica, Raymond P.
DOI:——
日期:——
Condensed 1,2,4-Triazines: Synthetic and Molecular Modeling Studies of 5,8-Dihydro-7-methylpyrazino[2,3-e]-1,2,4-triazines
作者:Cherng-Chyi Tzeng、Kuan-Han Lee、Yeh-Long Chen、Tai-Chi Wang
DOI:10.3987/com-96-7387
日期:——
5,8-Dihydro-7-methylpyrazino[2,3-e]-1,2,4-triazines (dihydroazapteridines) were prepared by Hinsberg reaction of 5,6-diamino-1,2,4-triazines with bromoacetone via a regiospecific fashion. The initial Z-form Schiff base intermediates cyclized to give 5,6-dihydro-7-methylpyrazino[2,3-e]-1,2,4-triazines which underwent pi redistribution to afford 5,8-dihydro-7-methylpyrazino[2,3-e]-1,2,4-triazines as final products.
TZENG, CHERNG-CHYI;MOTOLA, N. C.;PANZICA, R. P., J. ORG. CHEM., 1983, 48, N 8, 1271-1275
作者:TZENG, CHERNG-CHYI、MOTOLA, N. C.、PANZICA, R. P.