The Synthesis Of Ethyl 5-methyl-3-quinoxalinyl-isoxazole-4-carboxylate And Their Derivatives

Some heterocyclic compounds from glucose,fructose and arabinose possess many physiological activities.Such as: 2-phenyl-l, 2,3-triazol-4-carboxaldehyde derivatives have activities against cancer and virous. Tests with derivatives of quinoxalines show them to be highly active against mites, inflammations rhenmatism and allergies.In order to realize reinforcement of many physiological activities,we combine quinoxalinyl withisoxazole,l,3,4,-oxadiazoline,l,2,4-triazol-5-thione.The synthesis of quinoxaline-2-carboxaldehyde from o-phenylenediamine and fructose was too expensive because of its low yield.We improve its yield greatly on the base of previous methods.It has not been reported about 3-quinoxalinyl-isoxazole derivatives. With quinoxaline-2-carboxaldehyde, ethyl 5-methyl-3-quinoxalinylisoxazole-4-carboxylate was synthesized which involved 1,3-dipolar cycloaddition reactions. The present paper deals with:1. Starting with o-phenylenediamine and fructose, quinoxaline-2-carboxaldehyde was synthesized in high yield.2. Ethyl 5-methyl-3-quinoxalinylisoxazole-4-carboxylate, its 1,3,4- oxadiazoline, l,2,4-triazol-5-thione derivatives were synthesized. The Mannich bases of l,2,4-triazol-5-thione derivatives were alse synthesized.Their structures were established by elemental analysis, IR/H NMR and MS spectra.