ZrOCl(2 center dot)8H(2)O catalyzed solvent-free Friedlander synthesis of 1,8-naphthyridines

摘要

ZrOCl2 center dot 8H(2)O catalyzed Friedlander condensation of 2-aminonicotinaldehyde 1 with carbonyl compounds containing a-methylene group 2 has been achieved in solvent-free grinding conditions to give 1,8-naphthyridines 3. The yields are very good and purity is excellent. The method is preparatively convenient and useful.