Pyrolytic desulfurization ring contraction of condensed thiadiazines as a general route towards pyrazoloazines and pyrazoloazoles with a bridgehead (ring junction) nitrogen atom

被引：15

作者：

Ibrahim, Yehia A. ^{[1
]}

Al-Awadi, Nouria A. ^{[1
]}

John, Elizabeth ^{[1
]}

机构：

[1] Kuwait Univ, Fac Sci, Dept Chem, Safat 13060, Kuwait

来源：

TETRAHEDRON | 2008年 / 64卷 / 45期

关键词：

Pyrolysis; Ionic liquid; 1,2,4-Triazines; 1,2,4]Triazino[3,4-b][1,3,4]thiadiazin-4-ones; 1,3,4]Thiadiazino[2,3-b]quinazolines; 1,2,4]Triazolo[3,4-b][1,3,4]thiadiazines; Pyrazolo[5,1-c][1,2,4]triazin-4-ones; Pyrazolo[4,3-biquinazolin-9-ones; Pyrazolo[5,1-b][1,2,4]triazoles;

D O I：

10.1016/j.tet.2008.08.067

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Pyrolytic conversion of [1,2,4]triazino[3,4-b][1,3,4]thiadiazin-4-ones, [1,3,4]thiadiazino[2,3-b]quinazolin-10-ones and [1,2,4]triazolo[3,4-b][1,3,4]thiadiazines into their corresponding pyrazolo[5,1-c][1,2,4]triazin-4-ones, Pyrazolo[4,3-b]quinazolin-9-ones and pyrazolo[5,1-b][1,2,4]triazoles via desulfurization ring contraction is described. The starting condensed 1,3,4-thiadiazines were prepared from the corresponding readily available 4-amino-3-thioxo-1,2,4-triazin-5(4H)-ones, 3-amino-2,3-dihydro-2-thioxo-quinazolin-4(1H)-one and 4-amino-3(2H)-thioxo-1,2,4-triazoles upon reaction with the appropriate alpha-haloketones in two steps, or directly in one step in ethylpyridinium tetrafluoroborate (ionic liquid, IL). (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：10365 / 10374

页数：10