Abstract
Acetylation of the product obtained from successive reaction of dehydro-
L
-ascorbic acid with
o
-phenylenediamine and phenylhydrazine gave 3-[
L
-
threo
-2,3,4-triacetoxy-1-(phenylhydrazono)butyl]quinoxalin-2(1
H
)-one (
3
) rather than the cyclic structure (
4
) previously assigned for the reaction product. The structure of compound (
3
) was confirmed based on
1
H NMR,
13
C NMR, and X-ray analysis. Reinvestigation of the reaction of 5-phenylfuran-2,3,4(5
H
)-trione (
6
) with
o
-phenylenediamine and an arylhydrazine led to the isolation of two components (
7
) and (
10
). The former was found to exist in dimethyl sulphoxide solution as a tautomerie mixture of hydrazone imine and diazenyl enamine. Attempted acetylation of compound (
7
) afforded the furo[2,3-
b
]quinoxaline ring system (
8
).