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Tautomeric equilibria at room temperature were studied for three aromatic imine polyol compounds, previously reported 2‐((2‐hydroxybenzylidene)amino)‐2‐(hydroxymethyl)propane‐1,3‐diol 1 and two new compounds 2‐(((1,3‐dihydroxy‐2‐(hydroxymethyl)propan‐2‐yl)imino)methyl)benzene‐1,4‐diol 2 and 3‐(((1,3‐dihydroxy‐2‐(hydroxymethyl)propan‐2 yl)imino)methyl)benzene‐1,2‐diol 3. The dynamic behavior of these equilibria is described by a combination of IR, UV‐Vis and NMR spectroscopic measurements with DFT and TDDFT calculations in condensed phase. Among the different approaches, the combination of UV‐Vis experimental spectra with the oscillator strengths values estimated from TDDFT calculations allowed for the assessment of the tautomeric populations in DMSO and methanol. These results were consistent with different functionals employed GGA, Hybrid and MetaGGA. [ABSTRACT FROM AUTHOR]

In this work, the results of a study comparing the use of irradiation from different regions of the infrared spectrum for the promotion of several organic reactions, are presented and discussed. This use of eco-conditions provides a green approach to chemical synthesis. A set of ten different organic reactions were evaluated, including the Knoevenagel, Hantzsch, Biginelli and Meldrum reactions. It is important to highlight the use of a commercial device that produces infrared irradiation in the near infrared region and its distribution by convection providing heating uniformity, significantly reducing reaction times, achieving good yields and proceeding in the absence of solvent. It is also worth noting that a variety of different reactions may be performed at the same time. Finally, the products obtained were identified using TLC, together with corresponding MS-data, complementarily in comparison of NMR ¹H and 13C data with literature information. [ABSTRACT FROM AUTHOR]

The photodegradation of the proton pump inhibitor omeprazole (OME) in aqueous media with the system UV/O2 is presented. The photodegradation rate was assessed by HPLC and UV‐vis spectroscopy, while the mineralization rate was obtained by TOC measurements. Degradation products were investigated by IR spectroscopy and GC‐MS analysis. UV‐vis absorbance and HPLC results indicated that OME is completely degraded within 3 minutes of irradiation. TOC analysis indicated that intermediates compounds are relatively easy to mineralize since 80% mineralization is achieved within 2 hours. IR studies demonstrated a rapid oxidation of OME leading to the formation of amines and both sulfonic and carboxylic acids. GC‐MS data indicated that the initial photoproducts are derivatives of both benzimidazole and pyridine produced after the photochemical cleavage of the C–S bond. Plausible mechanisms for the direct and indirect degradation of OME are given. In the photochemical degradation of OME, many intermediate compounds are actually generated. Several of them were generated from hydroxyl radical reactions, but some of them resulted from rearrangements, reductive reactions, and through the formation of highly reactive intermediates such as pseudo carbene, thiooxirane, and sulfenamide. [ABSTRACT FROM AUTHOR]

The photodegradation of the proton pump inhibitor omeprazole (OME) in aqueous media with the system UV/O2 is presented. The photodegradation rate was assessed by HPLC and UV‐vis spectroscopy, while the mineralization rate was obtained by TOC measurements. Degradation products were investigated by IR spectroscopy and GC‐MS analysis. UV‐vis absorbance and HPLC results indicated that OME is completely degraded within 3 minutes of irradiation. TOC analysis indicated that intermediates compounds are relatively easy to mineralize since 80% mineralization is achieved within 2 hours. IR studies demonstrated a rapid oxidation of OME leading to the formation of amines and both sulfonic and carboxylic acids. GC‐MS data indicated that the initial photoproducts are derivatives of both benzimidazole and pyridine produced after the photochemical cleavage of the C–S bond. Plausible mechanisms for the direct and indirect degradation of OME are given. In the photochemical degradation of OME, many intermediate compounds are actually generated. Several of them were generated from hydroxyl radical reactions, but some of them resulted from rearrangements, reductive reactions, and through the formation of highly reactive intermediates such as pseudo carbene, thiooxirane, and sulfenamide. [ABSTRACT FROM AUTHOR]

In this work, the results of a study comparing the use of irradiation from different regions of the infrared spectrum for the promotion of several organic reactions, are presented and discussed. This use of eco-conditions provides a green approach to chemical synthesis. A set of ten different organic reactions were evaluated, including the Knoevenagel, Hantzsch, Biginelli and Meldrum reactions. It is important to highlight the use of a commercial device that produces infrared irradiation in the near infrared region and its distribution by convection providing heating uniformity, significantly reducing reaction times, achieving good yields and proceeding in the absence of solvent. It is also worth noting that a variety of different reactions may be performed at the same time. Finally, the products obtained were identified using TLC, together with corresponding MS-data, complementarily in comparison of NMR (1)H and (13)C data with literature information.

The title compound, C(27)H(39)N(3)O(2)·H(2)O, is a chiral pyridine-2,6-dicarboxamide derivative including cis-myrtanyl groups as amine substituents. The pyridine-2,6-dicarboxamide core approximates C(2) point symmetry and a solvent water mol-ecule lies on the pseudo-twofold axis. The water mol-ecule serves both as acceptor and donor for efficient hydrogen bonds involving N-H and C=O functional groups as donor and acceptor groups, respectively. As a result, each water mol-ecule in the crystal structure is tetra-hedrally bonded to three symmetry-related mol-ecules, forming a three-dimensional supra-molecular network. Such an arrangement is a common feature found in the majority of X-ray-characterized sym-metrically substituted pyridine-2,6-dicarboxamide derivatives.