Borohydride reduction of substituted isopropylidene methylenemalonates

Wright, Allen D.; Haslego, Mark L.; Smith, F.

doi:10.1016/s0040-4039(01)93963-2

Cited by 25 publications

(9 citation statements)

References 18 publications

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“…Compounds 1 a‐d , 1 e , 1 f , 1 g,h , 1 i , 1 k , 1 l , 1 m , 1 o , 1 p , 1 q,r , 1 s , 1 t , 2 , 3 , 4 , and 14 are known and their 1 H NMR spectra correspond to literature.…”

Section: Methodsmentioning

confidence: 76%

Novel type of carbon‐centered antioxidants arylmethyl Meldrum's acids − inhibit free radicals

Mieriņa

Jure

Zēberga

et al. 2017

Euro J Lipid Sci & Tech

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Monosubstituted Meldrum's acids are found out as a new class of powerful antioxidants. These compounds act as carbon radical scavengers due to the presence of acidic hydrogen in the moiety of cyclic 1,3‐dicarbonyl compound. The presence of phenol and benzylic moiety is favored, but these structural elements are not crucial for the antiradical activity in polar media. The antiradical and antioxidant activity of the substituted Meldrum's acids is not significantly affected by the substituents in the aromatic ring. The 5‐substituted 1,3‐dioxan‐4,6‐diones demonstrate high scavenging capacity of free radicals. The inhibition of DPPH and GO achieved even ∼100 and 80%, respectively. All substituted Meldrum's acids are better antioxidants than BHT, and activity of some of them even exceed vitamin C. It is found out that in polar media the compounds act via SPLET mechanism. Substituted Meldrum's acids turned out as powerful antioxidants for inhibition of oxidation processes of fatty acid alkyl esters, too. The oxidative stability of the last with the title compound additive was significantly higher than with BHT additive. It seems, that the antioxidant activity of the substituted Meldrum's acids in fatty acid esters is both due to benzylic position and 1,3‐dicarbonyl moiety. Practical applications: Arylmethyl Meldrum's acids should be highlighted as potential antioxidants for increasing oxidative stability of various products containing, for example, esters of poly‐unsaturated fatty acids. It should be admitted that the structure of the title compounds can be widely modified by substituents in the aromatic ring without remarkable loss of antioxidant and antiradical activity, but other properties (like solubility) may be improved. In order to apply the title antioxidants into products like cosmetics additional tests regarding toxicity are required. However, these antioxidants can be recommended for increasing oxidative stability for products used in technique. Monosubstituted Meldrum's acids act as carbon radical scavengers due to the presence of acidic hydrogen in the moiety of cyclic 1,3‐dicarbonyl compound. The substituted Meldrum's acids demonstrate high scavenging capacity of free radicals DPPH and GO. These compounds turned out as powerful antioxidants for inhibition of oxidation processes of fatty acid alkyl esters. The antioxidant activity of the substituted Meldrum's acids in fatty acid esters is both due to benzylic position and 1,3‐dicarbonyl moiety. Few of the monosubstituted Meldrum's acids were better antioxidants than BHT, TBHQ, α‐tocopherol, or vitamin C.

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“…Compounds 1 a‐d , 1 e , 1 f , 1 g,h , 1 i , 1 k , 1 l , 1 m , 1 o , 1 p , 1 q,r , 1 s , 1 t , 2 , 3 , 4 , and 14 are known and their 1 H NMR spectra correspond to literature.…”

Section: Methodsmentioning

confidence: 76%

Novel type of carbon‐centered antioxidants arylmethyl Meldrum's acids − inhibit free radicals

Mieriņa

Jure

Zēberga

et al. 2017

Euro J Lipid Sci & Tech

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“…In conjunction with an ongoing program [1], we needed a convenient supply of 5-ethyl Meldrum's acid (1) [2]. Because the selective monoalkylation of Meldrum's acid 2 is difficult and that the dialkylated product 3 generally predominates [3], we choose to use a reductive alkylation between acetaldehyde and Meldrum's acid and to reduce the alkylidene derivative 4, following the general method of Smith [4] (Figure 1).…”

mentioning

confidence: 99%

“…Thus we carried out a Knoevenagel reaction between acetaldehyde hemiacetal and the sodium salt of Meldrum's acid formed in-situ in methanol. After acidification, the resulting product was reduced with sodium borohydride [4,10]. Surprisingly, a new dimer 6 was isolated in 40% yield (Scheme 1).…”

mentioning

confidence: 99%

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On the synthesis of 5-ethyl meldrum's acid

Akué‐Gédu

El‐Hafidi

Rigo

et al. 2006

Journal of Heterocyclic Chemistry

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Reductive alkylation of Meldrum's acid with acetaldehyde can give, depending on the experimental conditions, either a new dimer (5‐[3‐(2,2‐dimethyl‐4,6‐dioxo‐1,3‐dioxan‐5‐yl)butyl]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione) or ethyl Meldrum's acid (2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione). A best way to obtain this latter product is synthesis of 1‐ethoxyethylidene Meldrum's acid from reaction of Meldrum's acid with triethyl orthoacetate, followed by a sodium borohydride reduction.

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“…Certain representatives of adducts 2 were reported to be obtained by following a synthetic route utilizing the condensation of aqueous formaldehyde, substituted indoles, and MeldrumÕs acid, 2 although other strategies have also been described in the literature for their preparation. 3,4 First, we attempted to apply the former method 2 to obtain several derivatives of compounds 2 . During our work, however, we encountered severe problems concerning the reproducibility of this procedure.…”

mentioning

confidence: 99%

Trimolecular Condensation of Substituted Indoles with Paraformaldehyde and Meldrum's Acid. Convective Heating versus Microwave Irradiation. A Comparative Study

Nemes¹,

Laronze²

1999

Synthesis

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Results obtained in a comparative study on the trimolecular condensation of substituted indoles 1 with paraformaldehyde and MeldrumÕs acid using convective heating vs. microwave irradiation are described. Both methods afforded adducts 2 together with their hydroxymethylated derivatives 3 in good yields. Although in both cases the yields are about the same, the microwave irradiation was found to be more advantageous, as this procedure makes possible to considerably reduce the reaction times and to obtain cleaner reaction mixtures.

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Borohydride reduction of substituted isopropylidene methylenemalonates

Cited by 25 publications

References 18 publications

Novel type of carbon‐centered antioxidants arylmethyl Meldrum's acids − inhibit free radicals

Novel type of carbon‐centered antioxidants arylmethyl Meldrum's acids − inhibit free radicals

On the synthesis of 5-ethyl meldrum's acid

Trimolecular Condensation of Substituted Indoles with Paraformaldehyde and Meldrum's Acid. Convective Heating versus Microwave Irradiation. A Comparative Study

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