Synthesis and Biological Activity of Heterocyclic Derivatives derived from Ethyl-2-hydroxyquinoxaline-3-carboxylate

Nadkarny-Sacasd Research Laboratories, St. Xavier's College, Mahapalika Marg, Bombay-400 001

Manuscript received 15 July 1985, accepted 17 February 1986

Ethyl-2-chloroquinoxaline-3-carboxylate obtained from ethyl-2-hydroxyquinoxa­line-3-carboxylate upon treatment with morpholine gave ethyl-2-morpholinoquinoxa­line-3-carboxylate (1). This ester upon reaction with hydrazine hydrate (99%) gave respec­tive carboxy hydrazide (2). This hydrazide on reaction with phenyl isothiocyanates gave thiosemicarbazides (3a-c). The thiosemicarbazides on reaction with concentrated sulphuric acid or anhydrous phosphoric acid gave 2-(4-substituted)-anilino-5-((2'-mor­pholino)quinoxalino)-1,3,4-thiadiazoles (4a-c). The thiosemicarbazides on reaction with 4% sodium hydroxide formed 4-(para-substituted-phenyl)-3-mercapto-5-((2'-mor­pholino) quinoxalino)-1,2,4-triazoles (5a-c), and on reaction with I₂ in KI gave 2 -(4 - substituted)anilino- 5-((2' - morpholino)quinoxalino)- 1,3,4 - oxadiazoles (6a-c).respectively.