SOLID-PHASE SYNTHESIS OF ED-7-CARBAMOYL-1,2,3,4-TETRAHYDROQUINOXALIN-2-ONES

The solid phase synthesis of ed-7-carbamoyl-1,2,3,4-tetrahydroquinoxal in-2-ones 8 is described. 4-Fluoro-3-nitrobenzoic acid is tethered to a solid support via the acid group. Aromatic substitution of the resin -bound aryl fluoride with an cl-amino ester is carried out in the pres ence of DIEA in DMF. The reduction of the aryl nitro group with SnCl2 . H2O and subsequent intramolecular cyclization result in the formatio n of the core quinoxalinone. Selective alkylation at the N-4 position of the quinoxalinone is accomplished with alkyl halides in the presenc e of K2CO3. The desired products are cleaved from solid supports and o btained in from 32 to 93% isolated yields.