The initial decomposition temperatures are for poly(VBOPE) 337[degrees]C, for oxime polymer 235[degrees]C, for phenylhydrazone
polymer 222[degrees]C, for thiosemicarbazide polymer 204[degrees]C and for sulfonic acid hydrazone polymer 222[degrees]C.
The 1,4-dianions of hydrazones, such as 4'-mehoxyacetophenone phenylhydrazone
or 4'-bromoacetophenonre carbomethoxyhydrazone, were prepared in excess lithium diisopropylamide and condensed with phthalic or 1,2-cyclohexanedicarboxylic anhydride, to give C-acylated intermediate that could be isolated or cyclized to the expected pyrazole-carboxylic acid.
Dilithiated oximes, phenylhydrazones
or carboalkoxyhydrazones were prepared in excess lithium diisopropylamide [LDA] and condensed with polylithiated methyl (2-amino-sulfonyl)benzoate to give C-acylated intermediates that can be isolated or cyclized to the 5-(2-amino-sulfonyl)phenyl-3-aryl-1H-pyrazoles and 5-(2-aminosulfonyl)pheny 1-3-arylisoxazoles.
The extension of the condensation-cyclization of acetophenones with other 1,4-dianion-type systems, such as dilihiated acetophenone phenylhydrazones
or carboalkoxyhydrazones, will also be presented.