2006-2010
Publicação 30
“Larvicidal activity of para-Benzoquinones”
De Sousa, D. P.; Vieira, Y. W.; Uliana, M. P.; Melo, M. A.; Brocksom, T, J.; Cavalcanti, S. C. H. Parasitol. Res.107, 741-745 , 2010.
DOI: 10.1007/s00436-010-1942-7
Abstract:
Plant products may be alternative sources of mosquito larval control agents, since they constitute a rich source of bioactive compounds that are biodegradable into nontoxic products. It has been reported that quinones and derivatives present toxic activity against mosquito larvae Aedes aegypti. Therefore, these facts led us to investigate the larvicidal potential of six structurally related para-benzoquinones against A. aegypti L. (Culicidae) larvae, the vector of dengue fever. All the para-benzoquinones were found to have larvicidal effect. The unsubstituted para-benzoquinone was the compound that exhibited the lowest potency, while 2-isopropyl-para-benzoquinone was the most bioactive. In general, the presence of alkyl groups results in more potent compounds. In addition, the number, position, and size of these groups modulate the potency of the compounds. The experimental results showed that by appropriate structural modification of para-benzoquinones, it may be possible to develop novel insecticidal compounds with potential use to control A. aegypti population.
Publicação 29
Synthesis of (R)-(-)-Carvone Derivatives
De Sousa, D. P.; Raphael, E.; Brocksom, T. J. Z. Naturforsch. 2010, 65b, 1381-1383.
DOI:
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Publicação 28
A Reação de Diels-Alder no Início do Século Vinte Um
Brocksom, T.J.; Donatoni, M. C.; Uliana, M. P.; Vieira, Y. W. Quim. Nova, 2010, 33, 2211-2218.
DOI: 10.1590/S0100-40422010001000034.
Abstract:
The Diels-Alder reaction continues to be the premier method for the construction of complex organic molecules. In the last 10 years many developments have been introduced, and have led to increased utility of this reaction. In this review we present some of these novelties, which are of fundamental importance in organic synthesis.
Publicação 27
O Prêmio Nobel de Química em 2010: União direta de carbonos sp2 e sp
Brocksom, T. J.; Alves, L. de C.; Wulf, G. D.; Desiderá, A. L.; de Oliveira, K. T.
Quim. Nova Esc 2010, 32, 233-239.
DOI:
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Publicação 26
Synthesis and Analgesic-like Effect of (6R, 4S)-6-(Methylene-para-Toluenesulfonamide)-para-Mentha-1,8-diene
De Sousa, D. P.; Nóbrega, F. F. de F.; de Almeida, R. N.; Brocksom, T. J. Z. Naturforsch, 2009, 64b, 351-355.
DOI:
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Publicação 25
Oxidation of Mono-Phenols to para-Benzoquinones: A Comparative Study
Uliana, M. P.; Vieira, Y. W.; Donatoni, M. C.; Corrêa, A. G.; Brocksom, U.; Brocksom, T. J.
J. Braz. Chem. Soc. 2008, 19, 1484-1489.
DOI: 10.1590/S0103-50532008000800007
Abstract:
The oxidation of mono-phenols to para-benzoquinones is of continuing interest due to the existence of numerous natural products containing this structural unit. The chemical reactivity of para-benzoquinones is also noteworthy, as oxidants and dienophiles in the Diels-Alder reaction. We have used for quite some time now, molecular oxygen and catalysis with [CoII(salen)] as the oxidation procedure, but felt the need for other oxidants and conditions to be of use with different phenol substrates. We now present our results on this important oxidation with a variety of oxidants, using eleven mono-phenols as substrates. The oxidants tested are cobalt, nickel, copper and vanadyl metals, with a selection of different salen type ligands. Completing this study we also investigated the use of hydrogen peroxide, OXONE®, dimethyl dioxirane and iodoxybenzoic acid.
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Publicação 24
“Regio- and Stereoselective Ring Opening of Epoxides with Sodium Phenylselenide under Phase Transfer Conditions”
Dos Santos, R, B.; Lacerda Jr., V.; Zanotto, P. R.; Brocksom, T. J.; Brocksom, U.
J. Chem. Res. 2008, 22-25.
Publicação 23
“A Síntese dos Sesquiterpenos Baquenolidas”
Brocksom, T. J.; Brocksom, U.; Constantino, M. G. Quim. Nova, 2008, 31, 937-941.
DOI : 10.1590/S0100-40422008000400037
Abstract:
The bakkenolide group of sesquiterpenes has been a focal point of synthetic efforts amongst several research laboratories all linked to our common origins at the Chemistry Institute at the State University in São Paulo. In this review we would like to present a historical perspective of this research, with unpublished background information, and a definitive retrosynthetic analysis of these molecules. This chemistry spans the time period from 1972 to 2006, and traces the initial steps with Prof. Dr. Helena Ferraz to the present day.
Publicação 22
“A Concise Synthesis of the 1,6-Disubstitiuted Eudesmane Sesquiterpene Carbon Skeleton”
Vieira, Y. W.; Nakamura, J.; Finelli, F. G.; Brocksom, U.; Brocksom, T. J. J. Braz. Chem. Soc. 2007, 18, 448-451.
DOI : 10.1590/S0103-50532007000200032
Abstract:
VIEIRA, Ygor Willian et al. A concise synthesis of the 1,6-disubstituted eudesmane sesquiterpene carbon skeleton. J. Braz. Chem. Soc.[online]. 2007, vol.18, n.2, pp. 448-451. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532007000200032.
Descrevemos uma síntese do esqueleto carbônico dos sesquiterpenos do grupo eudesmano substituído nos carbonos 1 e 6, que se baseia na versão multicomponente da reação de Diels-Alder.
Publicação 21
“Sedative Effect of Monoterpene Alcohols in Mice: A Preliminary Screening”
De Sousa, D. P.; Raphael, E.; Brocksom, U.; Brocksom, T. J. Z. Naturforsch. 2007, 62c, 563-566.
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Publicação 20
“O Programa NAS/CNPq: Avaliação de um Participante”
Brocksom, T. J.Quím Nova 2007, 30, 1394-1396.
Publicação 19
“Analysis of a cycloheptenone derivative: An experimental and theoretical approach”
de Oliveira, K. T. ; Lacerda Júnior, V. ; Constantino, M. G. ; Donate, P. M. ; da SILVA, G. V. J. ; Brocksom, T. J. ; Frederico, D.. SPECTROCHIM ACTA,2006, 63, 3, 709-713.
DOI : 10.1016/j.saa.2005.06.023
Abstract
A detailed analysis with total assignment of 1H and 13C NMR spectral data for a cycloheptenone derivative, a key intermediate for the synthesis of perhydroazulene terpenoids, is related. These assignments are based on 1D 1H and 13C NMR and on 2D NMR techniques including gCOSY, gHSQC, gHMBC, J-resolved and NOEDIF experiments. The unequivocal assignments were supported by theoretical chemical shifts and scalar coupling constant calculations at GIAO B3LYP/cc-pVDZ level from optimized structures at the same level of theory.
Publicação 18
“Core Structure of Eremophilanes and Bakkanes through Niobium Catalyzed Diels-Alder Reaction: Synthesis of (±)-Bakkenolide A”
Constantino, M. G. ; de Oliveira, K. T. ; Pollo, E. C. ; da Silva, G. V. J. ; Brocksom, T. J.
J ORG CHEM, 2006, 71, 9880-9883.
Abstract
A suitable intermediate for the synthesis of eremophilanes and bakkanes was prepared by a highly regioselective and stereoselective one-step synthesis through a niobium catalyzed Diels−Alder reaction. As a demonstration of the versatility of this intermediate, a total synthesis of (±)-bakkenolide A is described.
Publicação 17
“Synthesis and Antidepressant Evaluation of Three Para-Benzoquinone Mono-Oximes and Their Oxy Derivatives”
De Sousa, D. P.; Schefer, R. R.; Brocksom, U.; Brocksom, T. J. Molecules 2006, 11, 148-155.
Publicação 16
“The Enantioselective Synthesis of (R)-(+)-6-Isopropenyl-3-Methyl-2-Cycloheptenone”
Brocksom, T. J.; Brocksom, U.; Barbosa, F. P. J. Braz. Chem. Soc. 2006, 17, 792-796.
10.1590/S0103-50532006000400023
Abstract
BROCKSOM, Timothy J.; BROCKSOM, Ursula and BARBOSA, Fernanda P..The enantioselective synthesis of (R)-(+)-6-isopropenyl-3-methyl-2-cycloheptenone. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.4, pp. 792-796. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532006000400023.
(R)-(+)-6-isopropenyl-3-methyl-2-cycloheptenone is synthesized from (R)-(-)-carvone by reduction and trialkylsilyl-enolether formation, cyclopropanation with methylene iodide and diethylzinc, followed by a Saegusa type oxidation with ferric chloride and finally dehydrochlorination with base. The title compound is obtained in five steps and 38% overall yield, being a useful chiron for guaiane sesquiterpene natural products.