Preparation of indolylpropenylideneheterocycles for treatment of osteoporosis

Title compds. [I; R2-R4 = H, alkyl, (substituted) aryl; R5 = H, alkyl, (substituted) aryl; R6, R7 = H, OH, amino, alkoxy, (substituted) aryloxy, benzyloxy, alkylamino, dialkylamino, halo, CF3, OCF3, NO2, alkyl, carboxy, carbalkoxy, carbamoyl, alkylcarbamoyl; R6R7 = methylenedioxy, carbonyldioxy, carbonyldiamino; R8 = = H, OH, alkanoyl, alkyl, aminoalkyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, carbamoyl, aminosulfonyl; Z1Z2C = heterocyclic group], were prepd. Thus, Et [(2-ethenecarbonyloxy)ethoxy]diethoxyphosphorylacetate (prepn. given), tetramethylguanidine, and (E)-3-(5,6-dichloro-1H-indol-2-yl)prop-2-enal (prepn. given) in PhMe were heated at 100° overnight to give 6.9% (2Z,4E)-3-[3-(5,6-dichloro-1H-indol-2-yl)-2-propenylidene]-1,4-dioxan-2-one. The latter inhibited bafilomycin-sensitive chicken osteoclast ATPase with IC50 = 8.5 μM.