2016-atual
EM ATUALIZAÇÃO
Publicação 63
Chemistry of the Sesquiterpene Alkaloids
Brocksom, T. J.; de Oliveira, K. T.; Desiderá, A. L., J. Braz. Chem. Soc., 2017, 28, 933-942.
DOI: http://dx.doi.org/10.21577/0103-5053.20170049
Publicação 62
Combining Batch and Continuous Flow Setups in the End-to-end Synthesis of Naturally Occurring Curcuminoids.
Carmona-Vargas, C. C.; Alves, L. de C.; Brocksom, T. J.; de Oliveira, K. T. Reaction Chemistry & Engineering, 2017, 2, 366-374.
Abstract
A successful end-to-end continuous flow synthesis of pure curcumin (1) and two other natural derivatives present in turmeric is described. Batch and continuous flow conditions were combined in order to develop the end-to-end process. Three operations were telescoped yielding the three different natural curcuminoids in a safe, gram-scale and reproducible manner.
Publicação 61
Soluble and Non-aggregated Phthalocyanines: Synthesis, Mechanistic Aspects and Their Main Building Blocks.
Gobo, N. R. S.; Brocksom, T.J.; de Oliveira, K. T, Current Organic Synthesis, 2017, 14, 1-1.
DOI: 10.2174/1570179414666170403115907
Abstract
An overview on phthalocyanine chemistry and the principal synthetic precursors is presented. Strategies developed for obtaining soluble and non-aggregated phthalocyanine dyes are also covered, with insights on the reaction mechanisms. The main synthetic methods are presented, and different approaches to symmetric and non-symmetric systems discussed.
Publicação 60
E.Microbial Diversification of Diels-Alder Cycloadducts by Whole Cells of Penicilliumbrasilianum
Ud Din, Z.; Fill, T. P.; Donatoni, M. C.; dos Santos, C. A. A.; Brocksom, T. J.; Rodrigues-Filho, Mol. Divers, 2016.
DOI: 10.1007/s11030-016-9680-0
Abstract
Functionalizations of cycloadducts are important steps for the use of Diels–Alder reactions in the construction of complex cyclic or polycyclic molecules from relatively simple starting materials. In the present work, we studied the ability of Penicillium brasilianum to perform microbial transformations of racemic Diels–Alder endo-cycloadducts. Thus, Diels–Alder products, obtained from reacting cyclopentadiene or 2,3-dimethylbutadiene with alkylated para-benzoquinones, were transformed by the resting cells of P. brasilianum producing new functionalized polycyclic compounds. These biotransformations yielded novel products of oxidation and ring closure, reduction of the C=C or C=O in α,βα,β -unsaturated system, and allylic hydroxylations. The reduction products (conjugated double bond and carbonyl group) were also synthesized, and the enantioselectivity of both in vitro and in vivo processes was evaluated. In all cases, the microbiological transformations were enantioselective. In silico docking studies of the Diels–Alder cycloadducts with P. brasilianum oxidoreductase “old yellow enzymes” shed more light on these transformations.
Publicação 59
“Química Orgânica Experimental, Uma Abordagem de Química Verde”, Correa, A. G.; de Oliveira, K. T.; Paixão, M. W.; Brocksom, T. J., Elsevier, Rio de Janeiro, ISBN 978-85-352-8435-5, 2016.
Publicação 58
NIR Bacteriochlorin Chromophores Accessed by Heck and Sonogashira Cross-Coupling Reactions on a Tetrabromobacteriochlorin Derivative
De Assis, F. F.; Ferreira, M. A. B.; Brocksom, T. J.; de Oliveira. K. T., Org. Biomol. Chem., 2016, 14, 1402-1412.
Abstract
The synthesis of a new tetrabromobacteriochlorin BCBr4 is reported having the 3,4-dibromo-1H-pyrrole-2-carbaldehyde (10) as the major precursor. The BCBr4 was successfully employed in Pd cross-coupling reactions with methyl acrylate, phenyl acetylene and 4-ethynylanisole. In all three cases, the desired tetra-coupled products were obtained in good to excellent yields, and present a significant red shift in the UV-Vis bands above 800 nm. DFT and TD-DFT theoretical analyses of the NIR bacteriochlorin chromophores were performed in order to evaluate the effect of β substitution on their electronic structures.
Publicação 57
Porphyrins as Catalysts in Scalable Organic Reactions
Barona-Castãno, J; Carmona-Vargas, C; Brocksom, T. J; de Oliveira, K. T.. Molecules, v. 21, p. 310, 2016.
Abstract
Catalysis is a topic of continuous interest since it was discovered in chemistry centuries ago. Aiming at the advance of reactions for efficient processes, a number of approaches have been developed over the last 180 years, and more recently, porphyrins occupy an important role in this field. Porphyrins and metalloporphyrins are fascinating compounds which are involved in a number of synthetic transformations of great interest for industry and academy. The aim of this review is to cover the most recent progress in reactions catalysed by porphyrins in scalable procedures, thus presenting the state of the art in reactions of epoxidation, sulfoxidation, oxidation of alcohols to carbonyl compounds and C–H functionalization. In addition, the use of porphyrins as photocatalysts in continuous flow processes is covered.
Publicação 56
One-pot Sequential Functionalizations of meso-Tetrathienylporphyrins via Heck-Mizoroki Cross-coupling Reactions.
Donatoni, M. C; Vieira, Y. W. ; Brocksom, T. J. ; Rabelo, A. C; Leite, E. R.; de Oliveira, K.T. Tetrahedron Lett, v. 57, p. 3016-3020, 2016.
DOI:10.1016/j.tetlet.2016.05.106
Abstract
Synthesis and sequential functionalizations of a new meso-tetraiodo(thien-2-yl)porphyrin and its Ni(II) derivative are described. The reactions for the preparation of these new porphyrins were optimized. Subsequently, four successive one-pot Heck–Mizoroki cross-coupling reactions were studied using two acrylates and varied reaction conditions. We describe an optimized protocol for the preparation of highly conjugated thienylporphyrins with the potential to be used as dyes in solar cell devices as demonstrated in our preliminary studies.