A simple and efficient protocol for epoxidation of olefins using dimethyldioxirane

Ferraz, Helena M. C.; Muzzi, Rozanna Marques; Vieira, Tiago de O.; Viertler, Hans

doi:10.1016/s0040-4039(00)00769-3

Cited by 31 publications

(18 citation statements)

References 9 publications

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“…39 (salen)], were prepared as described in the cited references. Dimethyldioxirane 42 and iodoxybenzoic acid 43 were prepared according to published procedures.…”

Section: Methodsmentioning

confidence: 99%

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Uliana¹,

Vieira²,

Donatoni³

et al. 2008

J. Braz. Chem. Soc.

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A oxidação de mono-fenóis à para-benzoquinonas é assunto de interesse contínuo devido à existência de inúmeros produtos naturais contendo esta unidade estrutural. As para-benzoquinonas possuem reatividade química importante como agentes oxidantes e como dienófilos na reação de Diels-Alder. Usualmente nós preparamos as para-benzoquinonas pela reação de oxidação dos respectivos mono-fenóis com oxigênio molecular e catalisada por [Co II (salen)]. Porém, foi necessário estudar estas oxidações utilizando-se outros oxidantes. Nós apresentamos aqui nossos resultados sobre esta importante reação de oxidação com uma variedade de oxidantes, utilizando onze mono-fenóis como substratos. Os oxidantes utilizados foram cobalto, níquel, cobre e vanádio derivados com alguns ligantes do tipo salen. Também foram estudados peróxido de hidrogênio, OXONE®, dimetil dioxirano e ácido iodoxibenzóico.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 [Co II (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. Keywords: oxidation, alkyl-substituted phenols, para-benzoquinones IntroductionNatural products frequently occur containing the parabenzoquinone sub-structural unit within the global structure, as can be exemplified by vitamins K 1 and K 2 , co-enzyme Q (ubiquinone), 1 and in many terpenes and alkaloids. 2 These natural products 3-13 are associated with important biological properties, such as cardiovascular, anti-tumour, antibacterial, anti-germination and anti-protozoan among others. There is no doubt that the para-benzoquinone nucleus is an important charge transfer receptor and easily undergoes nucleophilic addition reactions. 1 The redox relation with para-hydroquinones (para-quinols) is of importance in biological activity, and also makes many simple para-benzoquinones excellent oxidizing agents. 1 Synthetically, the para-benzoquinone structural unit is an excellent dienophile for the Diels-Alder reaction, among other relevant reactions. 1 The usual and obvious manner to prepare parabenzoquinones 1,14,15 is from the corresponding parahydroquinones, which is however rather limited due to the lack of a wide range of commercially or synthetically available substrates. As a second choice, the simple monophenol is an ideal substrate due to the ready availability of an extremely wide range of...

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“…39 (salen)], were prepared as described in the cited references. Dimethyldioxirane 42 and iodoxybenzoic acid 43 were prepared according to published procedures.…”

Section: Methodsmentioning

confidence: 99%

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Uliana¹,

Vieira²,

Donatoni³

et al. 2008

J. Braz. Chem. Soc.

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“…[7,9,10] Then, the thiopropionamides were oxidized to the corresponding sulfoxides using 0.6 equivalent of oxone [potassium peroxymonosulfate (2 KHSO 5 ·KHSO 4 ·K 2 SO 4 )] in acetone solution and five equivalents of sodium bicarbonate. [11] These compounds were obtained in ca 80% yield. The pure sulfinyl-amides 1-4 are viscous liquids (a pair of diastereomers) that could not be resolved by chromatography on silica gel.…”

Section: Experimental Compoundsmentioning

confidence: 99%

Complete assignment of ¹H and ¹³C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

Domingues

Olivato

Reis

et al. 2008

Magnetic Reson in Chemistry

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“…1 (dd, J 1 = 6.87 Hz, J 2 = 11.08 Hz, 2H), 5.26 (m, 2H), and 5.83 (m, 1H). 11,14 The allyl phosphonate 3 (15.83 g, 0.0832 mol) and sodium bicarbonate (23.75 g, 0.286 mol) were dissolved/suspended in 150 mL of acetone at 0-5°C. Separately, Oxone (49.60 g, 0.0807 mol) was dissolved in 120 mL of distilled water and added in portions to the reaction mixture to minimize foaming.…”

Section: 23mentioning

confidence: 99%

New polyether diols as flame retardants for polyurethane: Derivatives of epoxy‐functionalized phosphonates and phosphates

et al. 2017

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SummaryPhosphorus-containing epoxides were used to generate several oligomeric polyether diols, which were in turn utilized in the preparation of model polyurethane (PU) samples, either as comonomers in the polymerization (Prep samples) or solvent blended into a priori prepared PU (Blend samples). The resultant samples were evaluated for heat release reduction potential using microcombustion calorimetry. Several variables were investigated in the oligomerization of the original epoxides, such as presence of initiator, epoxide comonomer, and solvent. The oligomer mixtures were thoroughly characterized, using NMR, mass spectrometry (MS), elemental analysis, and viscosity measurements. The final PU Prep samples were carefully analyzed to demonstrate and evaluate the degree of chemical incorporation of the polyether diols into the PU main chain.Results from the heat release studies demonstrated that incorporation of the phosphoruscontaining diol did lower flammability, but the structure of the original epoxide, as well as the oligoimerization conditions, had an effect on heat release reduction. The results are complex and require further study, but the phosphonate-based materials showed greater heat release reduction potential, both in the form of Prep and Blend samples, especially in one case of a Blend sample, where a notable amount of intumescent char was formed. KEYWORDS epoxides, flame retardancy, flammability testing, oligomers, phosphorus, polyurethanes 1 | INTRODUCTION Polyurethane (PU) foams, especially flexible foams, remain one of the largest fuel loads in the modern home. 1 These foams, should they ignite, can and will lead to catastrophic fire losses because of room flashover events. 2 While flame retardants are available for use today to lower the fire risk of PU foams, some of these flame retardants of small molecular size have been found to have environmental persistence issues, as well as negative bioaccumulation and toxicity profiles. 3 Further, the use of additives presents its own problem in that a small molecule flame retardant not chemically bound (through covalent bonds) to the PU matrix can slowly leach out over time, resulting in a loss of fire safety performance during the lifetime of the PU foam.There have been some attempts to address the additive issue by going to higher molecular weight/size molecules, such as oligomeric and polymeric flame retardants, which, should they migrate out of a polymer, present less of a bioaccumulation hazard. Still, what is mostly available for PUs today are small molecule flame retardant additives. The list of drawbacks of small molecule flame retardant additives leaves 3 other solutions (other than the use of sprinklers) that a fire protection engineer can use: barrier fabrics, conformal coatings, and reactive flame retardants.Barrier fabrics are currently being studied as a solution/replacement for flame retardant additives, but, these fabrics have their own drawbacks including fabrication issues, costs, and inability to protect against fire when the b...

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A simple and efficient protocol for epoxidation of olefins using dimethyldioxirane

Cited by 31 publications

References 9 publications

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Complete assignment of ¹H and ¹³C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

New polyether diols as flame retardants for polyurethane: Derivatives of epoxy‐functionalized phosphonates and phosphates

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A simple and efficient protocol for epoxidation of olefins using dimethyldioxirane

Cited by 31 publications

References 9 publications

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Oxidation of mono-phenols to para-benzoquinones: a comparative study

Complete assignment of 1H and 13C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives

New polyether diols as flame retardants for polyurethane: Derivatives of epoxy‐functionalized phosphonates and phosphates

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Complete assignment of ¹H and ¹³C NMR spectra of α‐phenylsulfinyl‐N‐methoxy‐ N‐methylpropionamide and some p‐substituted derivatives