Analysis of the IR., UV., and polarographic data of a variety of 2‐arylhydrazono‐3‐ketimino‐nitriles indicated that these derivatives exist mainly in the intramolecularly chelated hydrazone structure 1.
Compounds 1 reacted with hydrazine hydrate to yield the corresponding 5‐amino‐4‐arylazopyrazoles (3).
Compounds 3a reacted with acetylacetone, ethyl acetoacetate, and diethyl malonate to yield the pyrazolo[1, 5‐a]pyrimidine derivatives 4, 5, and 7 respectively. Compound 3a also reacted with benzoylisothiocyanate to yield the pyrazolyl thiourea derivative 8.
A series of twelve monosubstituted benzoylacetanilides have been prepared by condensation of acetoacetanilide with substituted benzoylchlorides. IR and UV spectral data are presented and discussed. The benzoyl CO stretching frequencies were correlated with σ+ (\barv=34.97σ++1705; r=0.983). The effect of substituents in the benzoyl moiety on the keto-enol equilibrium, has also been investigated. The data were correlated by the equation: logK=0.865σ+−0.615; r=0.988.
Von den Hydrazonen (I), die hauptsächlich als intramolekulare Chelate vorliegen (IR, UV, polarographische Daten), reagieren die Methylderi‐ vate (Ia,b) mit Hydrazinhydrat in siedendem Äthanol zu den Pyrazolen (IIa,b).
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