Ring Contraction
Mostrando 1-12 de 55 artigos, teses e dissertações.
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1. Synthesis of Spiro-Pyrrolidinyloxindoles by Oxidative Rearrangement of N-Acyltetrahydro-β-carbolines Using an Oxone/Aqueous Acetone Mixture
Spiro-pyrrolidinyl-2-oxindoles were prepared by the oxidative rearrangement of Na-acetyl-1,2,3,4-tetrahydro-β-carbolines (THBC) using dimethyldioxirane generated in situ. The Na-acetyl THBC substrates were obtained by Pictet-Spengler and acyl-Pictet-Spengler reactions of L-tryptophan methyl ester, followed by Na-acetylation. The stereoselectivity of the oxi
J. Braz. Chem. Soc.. Publicado em: 2019-01
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2. Vasoactive Thiomethyl-Pyrimidines: Promising Drug Candidates with Vascular Activity
Pyrimidines and their derivatives are present in various biologically active molecules. Most of the synthetic methods employed to achieve the pyrimidinone ring consist of two stages: the synthesis of a Michael intermediate from an aldehyde and an "active methylene" containing compound; and the condensation of this intermediate with a molecule containing an u
J. Braz. Chem. Soc.. Publicado em: 2017-07
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3. Iodine(III)-Mediated Ring Contraction Reactions: Synthesis of Oxygen- and Nitrogen-Substituted Indanes
The synthesis of oxygen- and nitrogen-substituted indanes was successfully performed by iodine(III)-mediated ring contraction of 1,2-dihydronaphthalenes. Acetoxy and benzoyloxy alkenes afforded indanes in 60-71% yield, irrespective of their position on aromatic ring. Similarly, the nitrogen containing substrates protected with 9-fluorenylmethyloxycarbonyl (F
J. Braz. Chem. Soc.. Publicado em: 2016-10
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4. Metal-free synthesis of indanes by iodine(III)-mediated ring contraction of 1, 2-dihydronaphthalenes
Um protocolo livre de metais foi desenvolvido para sintetizar indanos através da contração de anel de 1, 2-di-hidronaftalenos promovida por PhI(OH)OTs (HTIB ou reagente de Koser). Este rearranjo oxidativo pode ser realizado em diversos solventes (MeOH, CH3CN, 2 , 2, 2-trifluoroetanol (TFE), 1 , 1, 1, 3, 3, 3-hexafluoroisopropanol (HFIP), e uma mistura 1:4
Journal of the Brazilian Chemical Society. Publicado em: 2011-09
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5. Photoelastic analysis of stress generated by a silorane-based restoration system
Silorane-based composite, an epoxy material, was marketed as promising less polymerization contraction than conventional restorative materials. The aim of this study was to evaluate, by means of photoelasticity, the polymerization stress generated by a silorane-based composite. Thirty photoelastic rings with orifices measuring 5 mm (d) × 3 mm (h) were prepa
Brazilian Oral Research. Publicado em: 2011-08
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6. Renal and vascular effects of Crotalus durissus cumanensis venom and its crotoxin fraction
In this study, we evaluated the actions of Crotalus durissus cumanensis venom (CDCmV), and its crotoxin (Crtx) fraction, on renal and vascular functions in Wistar rats. In isolated perfused kidneys, CDCmV (10 µg/mL) significantly increased the perfusion pressure (PP) from 110.7 ± 2.4 to 125.3 ± 2.8 mmHg after 30 minutes. This effect was accompanied by an
Journal of Venomous Animals and Toxins including Tropical Diseases. Publicado em: 2011
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7. Desenvolvimento, caracterizacao e aplicacao da matriz FTO/POLI(3-aminofenol) na deteccao de marcador de lesao cardiaca por fotoluminescencia de quantum dots
The heart is a vital organ propelling blood, that carries oxygen and nutrients throughout the body, but whenever these components do not reach it due to arterial obstruction, there is an electrical instability in the process of contraction of the muscle, causing arrhythmias that often, in less than an hour, causes acute myocardial infarction. The problem and
Publicado em: 2011
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8. ESTUDO DOS EFEITOS RENAIS E VASCULARES DO VENENO DA SERPENTE Crotalus durissus cumanensis E CROTOXINA / RENAL AND VASCULAR EFFECTS FROM Crotalus durissus cumanensis VENOM AND CROTOXIN
Ophidian accidents involving species of the genus Crotalus, are usually serious and frequently fatal due to the frequency of acute renal failure. Unfortunately, there have been few studies of the toxinologic effects of Crotalus durissus cumanensis venom. The renal effects of the venom used in this study were observed by perfusion of isolated kidneys. Infusio
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/07/2009
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9. Diastereoselective total synthesis of (±)-trans-trikentrin A / Síntese total diastereosseletiva da (±)-trans-triquentrina A
Esta tese descreve uma nova abordagem para a síntese de ciclopenta[g]indóis baseada na reação de contração de anel mediada por trinitrato de tálio (TTN) de uma olefina tricíclica, que contém uma unidade indólica. Foi possível encontrar condições reacionais em que o sal de tálio(III) mostrou-se quimiosseletivo, reagindo com a ligação dupla do
Publicado em: 2009
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10. Ring Contraction of 1,2-Di-hydronaphthalenes with Iodine(III) and its Application in Total Synthesis of (±)-Indatraline / Reação de contração de anel de 1,2-di-hidronaftalenos com iodo(III) e sua aplicação na síntese total da (±)-indatralina
Esta tese mostra a síntese total da (±)-indatralina, representando uma aplicação sintética das reações de contração de anel de 1,2-di-hidronaftalenos mediadas por iodo(III). A molécula alvo é uma trans-3-fenil-1-indanamina, que é uma candidata para o tratamento de viciados em cocaína. Na rota proposta para a síntese da (±)-indatralina, o mater
Publicado em: 2008
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11. Síntese assimétrica do (+)- e do (-)-mutisiantol e obtenção de 1-tetralóis opticamente ativos / Asymmetric synthesis of (+)- and (-)-mutisianthol and preparation of optically active 1-tetralols
Esta tese descreve a primeira síntese assimétrica do sesquiterpeno fenólico (+)-(1S, 3R)-mutisiantol, assim como de seu enantiômero não-natural. O (+)-mutisiantol foi obtido em 11 etapas a partir do 2-metil-anisol, em rendimento global de 14% e excesso enantiomérico de 90%. Estas sínteses permitiram determinar a configuração absoluta deste produto n
Publicado em: 2008
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12. Studies toward the synthesis of jungianol and construction of benzofurans by TTN-mediated ring contraction / Estudos visando à síntese do jungianol e a construção de anéis benzofurânicos utilizando TTN
This thesis describes the studies aiming at the synthesis of jungianol and the construction of benzofuranic rings. In both cases, the key-step is the reaction of thallium(III)-mediated ring contraction. Jungianol is a phenolic sesquiterpene isolated by Bohlmann et al., in 1977, from the species Jungia malvaefolia. The key-step of the synthesis could be the r
Publicado em: 2007