When 6-(2-hydroxyethyl)amino-(I), 6-(3-hydroxypropyl)amino-(2), or 6-[2-(l-hydroxybutyl)]aminophenanthridines (3), dissolved in concentrated sulfuric acid, were treated with nitrosylsulfuric acid at 0-25", then diluted with water and basified with aqueous sodium hydroxide at 65-86", 2,3-dihydroimidazo-(4a-i), 1,2,3,4-tetrahydropyrimido-(5), or 2,3-dihydro-2-ethyl-H.-L. Pan and 'r. L. Fletcher Vol. 9