Double Anion Capture Reactions of Anthranilic Esters with Oxaldiimidoyl Dichlorides − Efficient Synthesis of 2,2′-Biquinazoline-4,4′(3H,3′H)-diones

Abstract

The reaction of anthranilic acids with oxaldiimidoyl dichlorides offers a new and convenient synthesis of quinazolin-4-ones. Condensation of anthranilic esters with diimidoyl dichlorides affords 2,2′-biquinazoline-4,4′(3H,3′H)-diones, which constitute a new class of dimeric heterocyclic compounds. In contrast, condensation of the dianion of N-methyl ortho-tolylamide with di(imidoyl) dichlorides affords seven- rather than six-membered ring products. Starting with 2-aminopyridine, 2,3-diimino-2,3-dihydroimidazo[1,2-a]pyridines could be efficiently prepared.