Pyrazoles. XXXIV. Ultraviolet spectra of pyrazole systems was written by Grandberg, I. I.. And the article was included in Zhurnal Obshchei Khimii in 1963.Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole This article mentions the following:
Ultraviolet spectra are reported for 117 substituted pyrazoles. Halogen atoms, alkyl, or NH2 groups produce a small bathochromic effect on the K band of pyrazole; in the presence of only these auxochromes the band is below 235 mμ; chromophores such as aryl groups, NO2, or NO groups, caused a shift of the K band to 242-80 mμ. The largest bathochromic shift occurs with auxochromes in 1- and 4-positions. If the group interaction between these substituents and the ring occurs through p-electrons, the bathochromic shift is small. Estimation of electron mobilities of heterocyclic rings on the basis of bathochromic band shifts resulted in the following series of ascending magnitude of the shift: 2-selenophene-yl, 2-thienyl, 2-furyl, Ph. The ferrocenyl radical as a substituent on the pyrazole ring acts as a typical auxochrome and does not conjugate with the pyrazole ring. Cf. CA 58,3290f. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole).
4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. The pyrazole ring is resistant to oxidation and reduction but the groups, such as alkyl and formyl attached to the ring, are oxidized to respective acids. Only electrolytic oxidation, ozonolysis, and a strong base cause ring opening.Application In Synthesis of 4-Chloro-3,5-dimethyl-1H-pyrazole
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics