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.