J. Chezal, E. Moreau, O. Chavignon
Jan 7, 2002
Citations
0
Influential Citations
16
Citations
Journal
Tetrahedron
Abstract
Abstract In order to study the regioselectivity of thermal cyclocondensation, aminoimidazo[1,2-a]pyridines (AIP) 5a–e were prepared, further converted into iminophosphoranes 7a–e , and ultimately converted regioselectively in angular annulated imidazonaphthyridines (IN) 8a , 10a , 11a , 12a or linear annulated dipyridoimidazole (DPI) 17a . From 2-substituted derivative 23 , the peri annulated product 24a was obtained. The starting amines 5a–f reacted with aldehydes to yield regioselectively IN 8a–c , 10a–c , 11a–c , 12a,b , DPI 16a–e , 17a–d and TIBO like structures (±)-13 and 24a–c , as proved by X-ray analysis. The 1,2- or 1,4-addition between amines and α,β-unsaturated aldehydes concerning the pyridine and imidazole moieties is discussed in the light of these results.