Iodocyclization of N-(2-nitrophenyl)- and N-phenyl-N’-[2-(alk-1-enyl)phenyl]ethanimidamides

The action of iodine on N-(2-nitrophenyl)- or N-phenyl-N’-[2-(alk-1-enyl)phenyl]ethanimidamides obtained by the condensation of 2-(cyclopent-1-enyl)-6-methylaniline with N-(1-chloroethylidene)aniline or N-(1-chloroethylidene)-2-nitroaniline results in corresponding spiro(3,4-dihydroquinazoline)-4,1’-(2’-iodocyclopentane) in good yields, but the analoguous reaction with 4-methyl-2- (1-methylbut-1-enyl)aniline leads to an N-[(2,3-dihydro-1H-indol-1-yl)ethyl]ideneaniline derivative.