like hydroxylamines and acyl or sulfonyl hydrazides led to the corresponding imine derivatives of the aldehyde. Hydrazine, alkyl and aryl hydrazines react with madurahydroxylactone under cyclization to give compounds of the new heterocyclic basic structure naphthaceno[1,2-g]phthalazine. Some new compounds strongly inhibit gram-positive bacteria, in part stronger than the parent compound.