Bruno Baehler

Étude de la bromation d'hydrazones d'aldéhydo-sucres

Abstract p -Nitrophenylhydrazones of aldehydo sugars have been treated with one equivalent of bromine. The presence of gem -bromoazo intermediates, which have been suggested for this type of reaction with an S E 2′ mechanism, have been demonstrated, and one of these compounds, 3- O -benzyl-5( R )-bromo-5-deoxy- 1,2- O -isopropylidene- 5( R )- p -nitrophenylazo-α- D -xylofuranose, was isolated in crystalline form. Two gem -bromoazo diastereoisomers were obtained from the same hydrazone. These rather unstable derivatives underwent a prototropic reaction, which led to the formation of the corresponding hydrazonoyl bromide.