A simple method for the regiocontrolled synthesis of the 4,5‐disubstituted N‐phenylpyrazole regioisomers 2 and 3 from β‐enamino diketones and phenylhydrazine is described. Pyrazole 2 was prepared regioselectively by carrying out the reaction in a protic solvent, whereas pyrazole 3 was obtained as the main product by using an aprotic solvent. Steric factors regarding the β‐enamino diketones also influenced the regiochemistry of 2 and 3. The influence of solvent on the reaction outcome can be rationalized by using Fukui indices. The structures of 2 and 3 were unambiguously elucidated by 1H and 13C NMR spectroscopy, two‐dimensional HMBC experiments, high resolution mass spectrometry, and X‐ray crystallographic analysis.
An enzyme which oxidizes 1 ,2-propanediol in the presence of NAD+ has been purified from lysates of Neisseria gonorrhoeae. The enzyme was activated by monovalent cations, had a pH optimum between 9 and 10, and showed a substrate specificity unlike any known alcohol or glycerol dehydrogenase. The enzyme had an apparent K, of 17 mM for 7,2-propanediol and 0.37 mM for NADf. When chromatographed on a Sephadex G-150 column, the enzyme eluted as a single peak in the molecular weight region of a bovine serum albumin marker. An antibody to the purified enzyme was prepared in goats. When antiserum was reacted with the enzyme in immunodiffusion experiments, a single precipitin band was detected. When the enzyme was mixed with an excess of antibody and then reacted with substrate, enzyme activity was completely inhibited.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.