Pesquisa

04/01/17 15:33

Publicações científicas dos membros do CERSusChem:

 

Angiotensin converting enzyme immobilized on magnetic beads as a tool for ligand fishing

de Almeida, F. G.; Vanzolini, K. L.; Cass, Q. B. J. Pharmac. Biomed. Anal. 2017, 132, 159–164. DOI: 10.1016/j.jpba.2016.10.006

Angiotensin converting enzyme (ACE) presents an important role in blood pressure regulation, since that converts angiotensin I to the vasoconstrictor angiotensin II.  In order to endorse this research field we have developed a new tool for ACE ligand screening. To this end, ACE was extracted from bovine lung, purified and chemically immobilized in modified ferrite magnetic beads (ACE-MBs). At the fishing assay, ACE-MBs were able not only to fish out the reference inhibitor, but also one peptide from a pool of tryptic digested BSA.

 

Sonochemistry in organocatalytic enamine-azide [3 2] cycloadditions: A rapid alternative for the synthesis of 1,2,3-triazoyl carboxamides

Xavier, D. M.; Goldani, B. S.; Seus, N.; Jacob, R. G.; Barcellos, T.; Paixao, M. W.; Luque, R.; Alves, D. Ultrasonics Sonochem. 201734, 107-114. http://dx.doi.org/10.1016/j.ultsonch.2016.05.007

The authors described the use of sonochemistry in the organocatalytic enamine-azide [3 2] cycloadditions of β-oxo-amides with a range of substituted aryl azides. These sonochemical promoted reactions were found to be amenable to a range of β-oxo amides or aryl azides, providing an efficient access to new N-aryl-1,2,3-triazoyl carboxamides in good to excellent yields and short times of reaction.

 

Magnetic ZSM-5 zeolite: a selective catalyst for the valorization of furfuryl alcohol to γ-valerolactone, alkyl levulinates or levulinic acid

Lima,T. M.; Lima, C. G. S.; Rathi, A. K.; Gawande, M. B.;Tucek, J.; Urquieta-González, E. A.; Zbořil, R.; Paixão, M. W.; Varma, R. S. Green Chem., 2016, 18, 5586-5593. DOI: 10.1039/C6GC01296E

A magnetic ZSM-5 zeolite with a core–shell type structure was synthesized, fully characterized and had its catalytic activity evaluated on the valorization of bio-derived furfuryl alcohol. The catalytic system displayed a tuneable selectivity to γ-valerolactone, alkyl levulinates and even levulinic acid by simply changing the reaction conditions. Furthermore, the catalyst could be easily recovered and reused for several reaction cycles without significant losses in its catalytic activity.

 

Continuous synthesis of hydantoins: intensifying the Bucherer–Bergs reaction

Monteiro, J.L.; Pieber, B.; Corrêa, A.G.; Kappe, C.O. Synlett 2016, 27, 83-87. DOI: 10.1055/s-0035-1560317

A continuous Bucherer-Bergs hydantoin synthesis utilizing intensified conditions is reported. The methodology is characterized by a two-feed flow approach to independently feed the organic substrate and the aqueous reagent solution. The increased interfacial area of the biphasic reaction mixture and the lack of headspace enabled almost quantitative conversions within ca. 30 minutes at 120 degrees C and 20 bar even for unpolar starting materials. In addition, a selective N(3)-monoalkylation of the resulting heterocycles under batch microwave conditions is reported yielding potential acetylcholinesterase inhibitors.

 

Multicomponent Synthesis of Cyclic Depsipeptide Mimics by Ugi Reaction Including Cyclic Hemiacetals Derived from Asymmetric Organocatalysis

de la Torre,A. F.; Rivera, D. G.; Concepción, O.; Echemendia, R.; Correa, A. G. ; Paixão, M. W. J. Org. Chem., 2016, 81, 803–809. DOI: 10.1021/acs.joc.5b02158

The synthesis of novel cyclic depsipeptide mimics by means of an organocatalytic conjugate addition, leading to chiral cyclic hemiacetals, followed by a multicomponent reaction with α-amino acids and isocyanides, is described. The initial organocatalytic step is employed for the asymmetric derivatization of α,β-unsaturated aldehydes to 4,5-disubstituted 2-hydroxytetrahydropyrans, which are next used as chiral bifunctional substrates on the Ugi five-center three-component reaction, giving rise to nine-membered-ring lactones.

 

Comparison of the regiospecific distribution from triacylglycerols after chemical and enzymatic interesterification of high oleic sunflower oil and fully hydrogenated high oleic sunflower oil blend by carbon-13 nuclear magnetic resonance

Lopes, T.I.B.; Ribeiro, M.D.M.M. ; Ming, C.C.; Grimaldi, R.; Goncalves, L.A.G.; Marsaioli, A.J. Food Chem. 2016, 212, 641-647. DOI:10.1016/j.foodchem.2016.06.024

The nutritional and organoleptic attributes of oils can proceed via interesterification of oils blends catalyzed by enzymes or chemicals. Enzymatic interesterification processes are preferred due the regiospecific outcome. Traditionally, monitoring of distribution of fatty acids  in glycerol backbone is performed by enzymatic and chromatographic methods that are time-consuming, involving a series of chemical manipulations employing large volumes of organic solvents. Alternatively, C-13 NMR is a fast and reliable technique that could be applied to determine the saturated and unsaturated FA distribution of the triacylglycerols present in high oleic sunflower oil  and fully hydrogenated high oleic sunflower oil blends and their interesterification products. The enzymatic interesterification was conducted employing the immobilized lipase from Thermomyces lanuginosus, the results show that the process was not completely regiospecific at sn-1,3 positions, due to the spontaneous acyl migration from position sn-2 to sn-1,3.