A straightforward synthesis of pyridopyrazino[2,3-b]indoles and indolo [2,3-b]quinoxaline

1,2-Diamines (ethylenediamine, o-phenylenediamine, 2,3-diaminopyridine, 3,4 -diaminopyridine) were reacted with 1-acetyl-2-bromo-3-indolinone to afford 5H-pyrazino [2,3-b]indoles, indole [2,3-b]quinoxaline and pyridopyrazino[2 ,3-b] indole in good yields. Alkylation of the indolic nitrogen atom of the se indolic derivatives with 2-chloroethylmorpholine, 2-chloroethyldimethyla mine and allyl bromide was carried out in order to obtain the corresponding N-alkylated derivatives.