2845-90-1Relevant academic research and scientific papers
Benzenepentamine - Its Easy Accessibility and Use in Syntheses of Pyrazinoquinoxalines
Praefcke, Klaus,Kohne, Bernd,Korinth, Frank,Psaras, Panicos,Nasielski, Jaques,et al.
, p. 617 - 622 (2007/10/02)
Benzenepentamine (6) has been rediscovered after about 60 years.A simple and very efficient synthetic route is described which yields the very sensitive, colourless 6 in methanolic solution in nearly quantitative yield.Condensations of 6 with two masked forms A and B of glyoxal conveniently lead to two types of amino-substituted pyrazinoquinoxalines, one with an angular phenanthrene-type topology (7a), or one with the linear anthracene-type structure (8a), respectively, with acceptable yields.The α-diketone benzil also reacts with 6, but less selectively, forming the corresponding tetraphenyl derivatives 7b and 8b of both these heterotricyclic ring systems.The heretofore unknown nitrobenzenepentamine (9), formed in addition to benzenehexamine in reduction reactions of 1,3,5-trinitrobenzenetriamine, has also been obtained.Based on spectroscopic data, the structures of these two multiamines have been deduced from their condensation products with α-diketones, in the case of the new pentamine 9 from its first derivatives 7c-e of pyrazinoquinoxaline.
