Pyrazolylquinoxaline derivatives from 3- [1- [phenyl-hydrazono] -l-threo-2,3,4-trihydroxyboutyl] -1H quinoxalin-2-one

Attempted benzylation of 3-[1-[phenylhydrazono]-L- threo-2,3,4-trihydroxybutyl]-1H-quinoxalin-2-one [I] gave 1-benzyl-3 [5-[hydroxymethyl]-1-phenylpyrazol-3-yl] quinoxalin- 2-one [II]. When III was subjected to the Vilsmeier-type reaction condition, no carbaldehyde derivative could be obtained but the product was 2-chloro-3-[5-[chloromethyl]-1-phenylpyrazol-3- yl] quinoxaline [V]. The acetyl derivative VI gave, under the same condition, 3-[5-[acetoxymethyl]-1-phenylpyrazol-3-yl]-2- chloroquinoxaline [VII]