Hydrazone

About: Hydrazone is a research topic. Over the lifetime, 4853 publications have been published within this topic receiving 65160 citations. The topic is also known as: hydrazone.

Solid-to-solid Reaction of 2,4-Dinitrophenylhydrazine with Several Aromatic Aldehydes Bearing Electron-donating Groups

Abstract: Aromatic 2,4-dinitrophenylhydrazones are conveniently prepared from 2,4-dinitrophenylhydrazyne and the corresponding aldehydes bearing electron-donating groups [N(Me)2, OMe and OH] in non-solvent reactions. The high-dilution method in the absence of basic or acidic catalysts is also efficient. According to X-ray data, planar conformation of the hydrazone molecules is stabilized by intramolecular NH…O2N hydrogen bond. Formation of 2D networks in the crystal is mediated via intermolecular CH…O2N hydrogen bonds.

Hydrazinolysis of some purines and pyrimidines and their related nucleosides and nucleotides

Abstract: Uracil and thymme and their related nucleosides and nucleotides are degraded quantitatively by treatment with hydrazine hydrate at 90°. The reaction products are, respectively, pyrazol-3-one, and 5-methylpyrazol-3-one together with, in the case of the nucleosides and nucleotides, approximately quantitative yields of urea and a sugar or sugar phosphate hydrazone. Cytosine and its derivative are similarly degraded but two heterocyclic products, 3-aminopyrazole and NN′-di(3-pyrazolyl)hydrazine are obtained. Adenine and guanine, their related nucleosides, and guanine nucleotides are not degraded by hydrazine hydrate at 90° but adenine nucleotides are slowly attacked. In this reaction the only degradation product which has been identified is inorganic phosphate.

Models and molecular orbital semiempirical calculations in the study of the spectroscopic properties of bovine serum amine oxidase quinone cofactor

Abstract: The electronic properties of 2,4,5-trihydroxyphenylalanine quinone (TPQ), the cofactor of bovine serum amine oxidase [Janes, S. M., Mu, D., Wemmer, D., Smith, A. J., Kaur, S., Maltby, D., Burlingame, A. L., & Klinman, J. P. (1990) Science 248, 981-987], and some adducts with hydrazines were investigated by means of low-molecular-weight models and semiempirical molecular orbital calculation methods. The enzyme visible band was assigned to the first pi-->pi* transition of the cofactor in p-quinonic form, with the C-4 hydroxyl ionized and hydrogen bonded either to a water molecule or to a basic protein residue. The spectra of the protein adducts with some substituted hydrazines were well accounted for by assuming the inhibitor bound to the C-5 carbonyl, usually in azo form. The adduct with the unsubstituted hydrazine was instead assigned an o-quinone hydrazone form, stabilized by an internal hydrogen bond between the amino group and the ortho carbonyl oxygen, a larger electron delocalization, and formation of a hydrogen bond at the C-6 ionized hydroxyl. On the basis of these assignments, the reaction of the protein with benzylhydrazine [Morpurgo, L., Agostinelli, E., Muccigrosso, J., Martini, F., Mondovi, B., & Avigliano, L. (1989) Biochem. J. 260, 19-25] was rewritten. All examined electronic transitions, though highly sensitive to cofactor ionization and hydrogen bonding, could be accounted for without introducing perturbations due to copper. This confirms that copper is not within bonding distance of the oxidized cofactor.