74102-37-7Relevant articles and documents
New binding modes of 1-acetyl- and 1-benzoyl-5-hydroxypyrazolines - Synthesis and characterization of O,O′-pyrazoline- and N,O-pyrazoline-zinc complexes
Someya, Chika I.,Inoue, Shigeyoshi,Irran, Elisabeth,Krackl, Sebastian,Enthaler, Stephan
experimental part, p. 2691 - 2697 (2011/08/02)
The 1-acetyl- and 1-benzoyl-5-hydroxypyrazolines 1a [3,5-CF3, 1-C(=O)CH3], 1b [3,5-CH3, 1-C(=O)CH3] and 1c [3,5-CF3, 1-C(=O)C6H5] have been synthesized in good yields and characterized by X-ray crystallography. The 1-acetyl- and 1-benzoyl-5-hydroxypyrazoline ligands were treated with dimethylzinc in a 1:1 molar ratio to form complexes 8 with a RO-Zn-Me motif. These complexes are accessible by simple Bronsted acid-base reactions generating methane as a side product. Characterization of complexes 8a and 8c by X-ray crystallography revealed a dimeric structure in the solid state. The two subunits generate a Zn2O2 square. The acetyl and benzoyl functionality of the ligands coordinate to the metal to span a six-membered ring. Moreover, the coordination mode of the ligand can be easily influenced by the addition of base. Here, N,N,N′,N′-tetramethylethylenediamine (tmeda) was applied to remove the acidic proton in the 4-position of the ligand and to cleave the hemiaminal functional group. The tmeda-H+ transfers the proton to the methyl group connected to the zinc and facilitates the removal of methane; the free tmeda coordinates to the zinc in a bidentate fashion. The positive charge at the zinc and the negative charge in the ligand recombine to form complex 9. Surprisingly, the characterization of complex 9c by X-ray crystallography showed the formation of the first zinc-based seven-membered system with covalent bonding (N1,O6-coordination) in the solid state, whereas for other metals O6,N2,O7-coordination has been reported. The versatility of 5-hydroxypyrazoline ligands has been demonstrated. Various zinc complexes have been synthesized and characterized resulting in new coordination modes of pyrazoline ligands depending on the reaction conditions; zinc dimers havebeen observed with a O,O′-coordination mode, whereas addition of tmeda to the reaction mixture led to the formation of a zinc-containing seven-membered ring system with an O,N-mode. Copyright
REACTIONS OF β-DIKETONES WITH ACYLHYDRAZINES
Yusupov, V. G.,Yakimovich, S. I.,Nasirdinov, S. D.,Parpiev, N. A.
, p. 371 - 374 (2007/10/02)
The reaction of acetylacetone with the hydrazides of aliphatic and aromatic acids was investigated.By IR and PMR spectroscopy it was shown that the products from condensation of acetylacetone with acylhydrazines exist at 1-acyl-3,5-dimethyl-5-hydroxypyraz
