Sugar-derived building blocks. Part 26. Hydrophilic pyrroles, pyridazines and diazepinones from D-fructose and isomaltulose

Efficient, large scale-adaptable protocols are described for the straightforward conversion of D-fructose-derived 5-hydroxymethylfurfural (HMF) and of 5-glucosyloxymethylfurfural (alpha GMF, from isomaltulose) into hydrophilically substituted N-heterocycles of the pyrrole, pyridazine, thiophene and benzodiazepine type. Key intermediates are 1,6-dihydroxy-2,5-hexenediones, readily generated by oxidative furan ring-opening.