Total synthesis of new indolo[2,3-a]quinolizine alkaloids sempervirine type, potential pharmaceuticals

Seven new pentacyclic alkaloids sempervirine type have been synthesized via the AB-DE synthons obtainable by Fischer indolization of fused pyridines acetyl derivatives, which were formed in Diels-Alder reaction of 1,2,4-triazine precursor with cyclic enamines. New indolopyridocoline methoxy analogue has been obtained in the model synthesis from 2-acetylpyridine.