Zur Synthese und Struktur von 8-Nitro-imidazo [1,2-a]pyridinen

Summary The title compounds were synthesized by reaction of nitroketene aminals with -chlorovinylcarbonyl compounds. The chloromethylene malononitriles1 react with nitromethylenimidazolin (2 a) and -benzimidazoles2 b to yield the 8-nitro-2,3-dihydroimidazo1,2-a]pyridines3 and the 4-nitropyrido1,2-a]-benzimidazoles6, both containing an amino group. Analogously, from the special 3-chloro-2-propeniminium salt7 and2 a the imidazopyridine derivative9 was formed. The 3-aryl-3-chloro-2-propeniminium salts10 were converted into the nitro-dihydroimidazo1,2-a]pyridines11 and the pyrido1,2-a]benzimidazole12 containing the aryl group by reaction with2 a and2 b, respectively. The structures were investigated by 2-dimensional¹H/¹³C-NMR-spectroscopy.