Crystal and molecular structure of acetamidrazone derivatives

N-1-acetylacetamidrazones and N-1-benzoylacetamidrazones (1a-d) were characterized by H-1 and C-13 NMR spectroscopy. The actual tautomeric form present has been shown to be the amide hydrazone. NMR spectra of N-1-acetylacetamidrazones (1a,b) showed the existence of Z and E isomers in solution, while N-1-benzoylacetamidrazones (1c,d) were present as Z isomers. The crystal structures of the amidrazones have been determined at 173 and 293 K, respectively. The amidrazones 1c and 1d crystallize in the monoclinic system: in particular for le space group P2(1)/c, with a = 11.016(5), b = 20.594(14), c = 13.657(7) Angstrom; beta = 98.29(3)degrees; V = 3066(3) Angstrom(3) and D-c = 1.243 g/cm(3) for Z = 4; for Id space group P2(1)/a, with a = 9.410(5), b = 10.449(3), c = 14.295(l 1) Angstrom; beta = 101.04(5)degrees; V = 1380(l) Angstrom(3) and D-c = 1.220 g/cm(3) for Z = 4. The X-ray diffraction analysis carried out on 1c has shown the presence of three molecules in the asymmetric unit which differ for the orientation of the phenyl ring.