Synthesis of new tetrahydropyridopyrazine derivatives via continuous flow chemistry approach and their spectroscopic characterizations

Abstract

We report here the synthesis of different substituted tetrahydropyridopyrazine derivatives. This approach of synthesis has been designed in a way that in first simple chloro-amine coupling as an alternative of Buchwald coupling followed by heterogeneous hydrogenation of nitro to give amine and further cyclization of this amine with carboxylic acid was accomplished in a single process with the help of continuous flow hydrogenation reactor. This processing was a generation of hydrogen (in situ) by electrolysis of water molecule and using a prepacked cartridge of a palladium catalyst. In a further step, LAH was used to reduce lactam to a yielding product as tetrahydropyridopyrazine (TPP) scaffold. Final adducts were obtained using substituted benzoyl and sulfonyl derivatives.