Structural study of tropane-3-spiro-4'-imidazol-5'-one

Tropane-3-spiro-4'-imidazol-5'-one has been synthesized and its crystal and molecular structures determined by X-ray diffraction, IR, Raman, 1H-NMR and 13C-NMR methods. The tautomeric equilibrium between this structure and the corresponding conjugated form in different solvents is also studied from IR and UV data. The imidazoline ring, the spiranic C(3, 4'), the N(8) and the methyl C(9) atoms are situated in a plane. The piperidine ring adopts a distorted chair conformation in the crystalline form and in solution. The flattening of the C(1), C(2), C(3, 4'), C(4), C(5) part of the chair and the opposite puckering are noticeably large. In order to complete the results, some spectroscopic measurements have also been made for the tropane-3-spiro-4'-imidazol-5'-one hydrochloride. © 1981.The authors thank the Centro por Proceso de Datos del Ministerio de Educación, Madrid, Spain, for providing facilities for the use of the 1108 Univac computer.Peer Reviewe

Structural and spectroscopic study of condensed piperidine bicyclanols. 3-Phenethyl-3-azabicyclo[3.2.1]octan-8-α-ol

The IR and 1H and 13C NMR spectra of 3-phenethyl-3-azabicyclo[3.2.1]octan-8-α-ol have been studied in several media, and its crystal structure has been determined by X-ray diffraction. The bicyclic system adopts a chair-envelope conformation with both OH and phenethyl groups in equatorial positions with respect to the piperidine ring. The existence of OH⋯N intermolecular hydrogen bonding in the solid state has been revealed by X-ray and IR data. The results obtained are compared with those previously found for the corresponding β-epimer. © 1989.We thank A. Gómez Morillas, Instituto de Estructura de la Materia, CSIC, Madrid for recording ‘H NMR spectra.Peer Reviewe

Structural Study of Benzidamine Salicylate in the Solid State and in Solution

The vibrational (IR and Raman) and H and C NMR spectra of the analgesic and anti‐inflammatory benzidamine salicylate (Benzasal) have been examined, and the results are described. The crystal structure of this compound has been determined by X‐ray diffraction. To assist in interpretation of the spectroscopic data, some measurements of benzidamine, benzidamine hydrochloride, and salicylic acid have also been made. The most important intermolecular interactions of benzidamine salicylate in the solid state are NH…C hydrogen bonds involving both salicylate oxygen atoms (d = 2.658 Å and 3.228 Å). At least the stronger hydrogen bond remains in CDCl solution. Moreover, the strong intramolecular hydrogen bond O‐H……C within the salicylate anion has also been observed in the solid state and in solution

Structural and conformational study of diazabicyclanones and diazabicyclanols

3-Methyl-7-alkyl-3,7-diazabicyclo [3.3.1] nonan-9-ones and 9-ols have been studied by 1H, 13C NMF_IR and Raman spectroscopy and the crystal structure of 3,7-dimethyl-3,7-diazabicyclo[8.3.1] nonan-9-ol has been determined by X-ray diffraction. The ketones studied adopt in CDCl3 and (CD3)2SO solution a flattened chair-chair conformation; however, in the crystalline N-methyl N-benzyl derivative, the bicyclic system adopts a chair-boat conformation. X-ray data for 3,7-dimethyl-3,7-diazabicyclo [3.3.1] nonan-9-ol have revealed that the compound has crystallized in a chair-chair conformation stabilized by water and ethanol molecules. Frc.a IR data the existence of another chair anhydrous crystalline form stabilized by intramolecular hydrogen bonding has been deduced. The preferred conformation in solution of the diazabycyclanols mainly depends on the polarity of the solvent. © 1985.We thank Dr. M. Martínez, Department of Organic and Pharmaceutic Chemistry, University of Madrid for alcohol sample Dr. M. Rico-Sarompa Institute de Estructura de la Materk C.S.I.C., Madrid, for recordi~ 360 MHz NMR Specka, and the Comisión Asesora de Investigación Cien tífica y Técnica (Grant 1750) for partial support of this research.Peer Reviewe

Synthesis and structural study on α-substituted-1-styrylpyridinium salts. Reinvestigation of krohnke condensation

Kröhnke condensation of several cycloimmonium salts with p-dimethylaminobenzaldhyde has been studied. X-Ray diffraction, IR and Raman spectra, 1H-and 13C-NMR and UV spectra of the products are discussed, being compared, when necessary, with the starting pyridinium salts. All compounds showed the Z configuration, corresponding to the more stable structure, except one, in which steric factors were predominant

Synthesis and structural study on α-substituted-1-styrylpyridinium salts. Reinvestigation of krohnke condensation

Kröhnke condensation of several cycloimmonium salts with p-dimethylaminobenzaldhyde has been studied. X-Ray diffraction, IR and Raman spectra, 1H-and 13C-NMR and UV spectra of the products are discussed, being compared, when necessary, with the starting pyridinium salts. All compounds showed the Z configuration, corresponding to the more stable structure, except one, in which steric factors were predominant