Synthese von Imidazo- und Diimidazo[1,2,4,5]tetrazinen; zur Tautomerie von Dihydro-1,2,4,5-tetrazinen
作者:Heinrich Wamhoff、Harald W. Strobl、Martin Jansen、Martina Ralle
DOI:10.1055/s-1992-26251
日期:——
Synthesis of Imidazo- and Diimidazo[1,2,4,5]tetrazines; For Tautomerism of Dihydro-1,2,4,5-tetrazines Dimethyl 1,4-dihydro-1,2,4,5-tetrazine-3,6-dicarboxylate (1) reacts with isocyanates to afford the 2,7-disubstituted 1H6H -diimidazo[1,5-b: 1′,5′-e] [1,2,4,5]tetrazine-1,3,6,8(2H,7H)-tetrones 2a-m, a hitherto unknown ring system. The linear annulation of 2m was established by X-ray analysis, and as a consequence the 1,4-dihydro tautomer found to be the main constituent of all other potential isomers. Compound 1 reacts with isothiocyanates to give the corresponding 1,6-dithioxo derivatives 5a,b as well as the 7-substituted methyl 2,6,7,8-tetrahydro-8-oxo-6-thioxoimidazo[1,5-b] [1,2,4,5]tetrazine-3-carboxylates 6b,c respectively, while the unsymmetrically substituted 2-tert-butyl-7-(4-chlorophenyl)-6-thioxo-1H, 6H-diimidazo[1,5-b: 1′,5′-e] [1,2,4,5]tetrazine-1,2,8-(2H,7H)-trione (8) is obtained from 6c and the corresponding isocyanate.
咪唑并二咪唑[1,2,4,5]四嗪的合成;对于二氢-1,2,4,5-四嗪的互变异构 1,4-二氢-1,2,4,5-四嗪-3,6-二甲酸二甲酯 (1) 与异氰酸酯反应,得到 2,7-二取代的1H6H -二咪唑并[1,5-b: 1′,5′-e] [1,2,4,5]四嗪-1,3,6,8(2H,7H)-四酮2a-m,一种迄今为止未知的化合物环系统。通过 X 射线分析确定了 2m 的线性成环,因此发现 1,4-二氢互变异构体是所有其他潜在异构体的主要成分。化合物1与异硫氰酸酯反应得到相应的1,6-二硫代衍生物5a,b以及7-取代的甲基2,6,7,8-四氢-8-氧代-6-硫代咪唑[1,5-b] [1,2,4,5]四嗪-3-羧酸酯分别为6b,c,而不对称取代的2-叔丁基-7-(4-氯苯基)-6-硫代-1H,6H-二咪唑[1,5 -b:1',5'-e][1,2,4,5]四嗪-1,2,8-(2H,7H)-三酮(8)由6c和相应的异氰酸酯得到。