J. Bellanato

Structural and conformational study of diazabicyclanones and diazabicyclanols

Abstract 3-Methyl-7-alkyl-3,7-diazabicyclo [3.3.1] nonan-9-ones and 9-ols have been studied by 1 H, 13 C 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 CDCl 3 and (CD 3 ) 2 SO 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.

Infrared and Raman spectroscopy of urinary calculi: A review

The application of infrared and Raman spectroscopic techniques to the analysis of urinary calculi is reviewed and their relative efficiency and adaptability to routine analysis are discussed. Using the classification of urinary calculi based on their main constituents, infrared and Raman spectra of calcium oxalates, phosphates, uric acid, urates, and cystine are reported. Some characteristic bands are suggested as useful for analytical purposes. References to other constituents such as drugs are included. Although this review is aimed principally at human stones, it also extends to literature references dealing with urinary calculi from canine, feline, and equine animal species.

Structural and conformational study of 3-phenethyl-3-azabicyclo[3.2.1] octan-8-β-ol

Abstract The infrared and 1 H and 13 C NMR spectra of 3-aza-bicyclo[3.2.1]octane-8-β-ol have been examined in several media. To assist in interpretation of the spectroscopic data, the crystal structure has been determined by X-ray diffraction. The bicyclic system adopts a chair—envelope conformation with OH and phenethyl groups, respectively, in axial and equatorial positions with respect to the piperidine ring. The crystal structure is stabilized by means of OH…N intermolecular hydrogen bonding. In CCl 4 solution the initial chair—envelope conformation changes to a boat—envelope conformation which is stabilized by an intramolecular hydrogen bond. The unambiguous assignment of all protons of the bicyclic system, not previously described, has also been carried out.

Spectroscopic study of some condensed piperidine bicyclanols

Abstract The infrared and 1 H and 13 C NMR spectra of 3—phenethyl—3— azabicyclo [3.3.1] nonan—9—α(β)—ol ( I α and I β) and 8—phenethyl—8—azabicyclo [4.3.1] decan—10α—ol ( II ) have been examined in several media. The NMR data for I show that this compound has crystallized as an epimeric mixture of I α and I β. Both structures adopt in CDCl 3 and (CD 3 ) 2 SO solution a flattened chair—chair conformation with the phenethyl group in equatorial positions with respect to the flattened piperidine ring. The IR spectra show the existence of intermolecular hydrogen bonding (presumably OH⋯N) in solid state. The NMR data for II indicate that both OH and phenethyl groups are in equatorial positions. The IR and Raman data for this compound in solid state indicate OH⋯N intermolecular hydrogen bonding.

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

Abstract The IR and 1 H and 13 C 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 OH⋯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.

Vibrational and structural study of 2-amino-4H-pyran derivatives

Abstract Seven 2-amino-4 H -pyran derivatives have been studied by IR and Raman spectroscopy and the crystal structure of one (2-amino-3,5-dicyano-4-isopropyl-6-methyl-4 H -pyran) has been determined by X-ray diffraction. For the purposes of comparison 3,5-dicyano-2,6-dimethyl-4-phenyl-4 H -pyran has also been studied. The seven 2-amino-4 H -pyran derivatives considered contain an enaminonitrile system in their structure and present similar spectroscopic characteristics. However, the electronic properties of the substituents at the C(5) and C(6) atoms induce frequency and intensity changes in the corresponding ν(CC) IR and Raman band (“γ-pyran” band) and consequently in the degree of coupling with the ν(CC) of the C(2)C(3) bond (enamine band). The spectra reveal differences in the strength of hydrogen bonding and in the “planarity” of the ring. X-ray data for 2-amino-3,5-dicyano-4-isopropyl-6-methyl-4 H -pyran show that the conformation of the pyran ring is a distorted boat. The N⋯NC intermolecular distances also indicate weak intermolecular hydrogen bonds in the crystal between the amino group of each molecule and two cyano groups of two neighbouring molecules.

Spectral and structural study of the 4H-pyran ring containing an enaminoester moiety

Abstract The structural and spectral properties of a pyran ring containing an enaminoester moiety are described. Structural parametes and IR and Raman data are given. The results obtained indicate an almost planar heterocyclic ring and a complex hydrogen bonding situation. The vibrations of the mesomeric enaminoester system are discussed. For the purpose of comparison, spectral data of a more simple 4 H -pyran are also given.

Synthesis, spectroscopic and crystallographic study of some carbamates from an azabicyclic chloroformate and primary heterocyclic amines

A series of benzimidazole, thiazole and benzothiazole carbamates derived from 9-methyl-9-azabicyclo[3.3.1]nonan-3β-ol was synthesized and studied by 1H, 13C, 2D NMR and IR spectroscopy. The crystal structure of N-(benzimidazol-2-yl)-9-methyl-9-azabicyclo[3.3.1]nonan-3β-yl-carbamate (8) was determined by X-ray diffraction. It has been found that two different carbamates can be obtained in the case of the benzimidazole derivatives. The structure of the studied compounds corresponds to the amino form of the molecules and show different types of hydrogen bonds. In CDCl3 solution all the carbamates displayed a preferred flattened chair-chair conformation similar to that observed for compound 8 in the solid state.

Infrared and atomic spectrometry analysis of the mineral composition of a series of equine sabulous material samples and urinary calculi

Atomic spectrometry has been used in 20 samples of equine urinary sabulous deposits in order to detect minor elements accompanying the predominant element, calcium, which is present in the form of calcium carbonate (calcite and/or vaterite). The elements measured have been (besides calcium) magnesium, sodium, potassium, iron, copper and manganese. Phosphates, sulphates and silica are frequently present as minor constituents of equine urinary sabulous deposits and uroliths, but their detection can be difficult by infrared (IR) spectroscopy in the original samples due to overlapping with the bands of calcium carbonate. For that reason, the calcination residues of six urinary calculi and 33 samples of sabulous material have been studied by IR spectroscopy and energy dispersive X-ray (EDX) analysis. The results confirm the presence of the above mentioned minor constituents in most samples studied.

Structural study on propenylphosphonates

Abstract The 1 H and 13 C NMR, IR and Raman spectra of several cis and trans propenylphosphonic acid derivatives have been measured and discussed. In some compounds NMR chemical shifts and IR data suggest that the PO and CC groups are in a planar s- trans disposition.