Chloroacetic acid-promoted heterocyclic reactions: Efficient preparation of tetrahydropyridines and 2,3-dihydroquinazolin-4(1H)-ones

Facile and versatile procedures have been explored for the synthesis of tetrahydropyridines and 2,3-dihydroquinazolin-4(1H)-ones. These protocols employ the one-pot multi-component condensation of arylaldehydes and aromatic amines with β-keto esters and isatoic anhydride in chloroacetic acid, respectively. The reactions proceeded smoothly to generate the corresponding products in high yield. We have found that the use of chloroacetic acid as catalyst results in a remarkable beneficial effect on the reaction, allowing it to be performed without the need of any co-catalyst, which is the case in other similar reported methodologies. In addition, the preparation of 2,3-dihydro-4(1H)-quinazolinones derivatives from the reaction of arylaldehydes and anthranilamide in the presence of mentioned catalyst is reported.