1012-12-0Relevant articles and documents
Substituent Effects on the Enantioselective Hydrocyanation of Aryl Aldehydes
Kim, Hyun J.,Jackson, W. Roy
, p. 1541 - 1548 (1994)
A detailed study of the dipeptide catalysed enantioselective hydrocyanation of a series of O-substituted 4-hydroxybenzaldehydes has shown that adverse steric effects can occur leading to low enantiomeric excess (e.e.) values when the substituent is long and flexible.Similar hydrocyanation of several derivatives of 3,4-dihydroxybenzaldehydes have been shown to give very variable values of e.e.Hydrocyanation of 3,5-dimethoxy and 3,4,5-trimethoxybenzaldehyde consistently gave low values of e.e.
PhIO-Mediated oxidative dethioacetalization/dethioketalization under water-free conditions
Du, Yunfei,Ouyang, Yaxin,Wang, Xi,Wang, Xiaofan,Yu, Zhenyang,Zhao, Bingyue,Zhao, Kang
, p. 48 - 65 (2021/06/16)
Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.
Syntheses of polyfunctionalized resveratrol derivatives using Wittig and Heck protocols
Chalal, Malik,Vervandier-Fasseur, Dominique,Meunier, Philippe,Cattey, Hélène,Hierso, Jean-Cyrille
experimental part, p. 3899 - 3907 (2012/07/14)
Improved protocols for Wittig reaction and palladium-catalyzed Heck coupling give expedient access to a series of unprecedented polyfunctionalized artificial-resveratrol derivatives. In the modified Wittig protocol, trimethylsilyl was used as a highly valuable protective group of the phenolic functions of starting aromatic materials. A clean O-alkylation of hydroxylated stilbenes with ethylene carbonate was also conducted. Thus, Wittig reaction followed by hydroxyethylation take place one-pot with only carbon dioxide as waste. Additionally, a palladium-catalyzed Heck coupling strategy was developed by using ferrocenyl phosphane ligands, and multi-functionalized hydroxylated stilbenes were obtained without the need of any protection/deprotection sequence. Up to six functional groups are introduced by these procedures, which limit the number of reactions steps, the waste toxicity, and the use of costly reagents.
Photolytic decarboxylation of α-arylcarboxylic acids mediated by HgF2 under a dioxygen atmosphere
Farhadi, Saeid,Zaringhadam, Parisa,Sahamieh, Reza Zarei
, p. 1965 - 1968 (2007/10/03)
Mercuric fluoride (HgF2), as a light-sensitive inorganic compound, in the presence of dioxygen is able to convert various α-aryl- and α,α-diarylcarboxylic acids into the corresponding aldehydes and ketones selectively under photoirradiation via trapping of the benzylic radical by O2.
Chromophoric photocrosslinking compound
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, (2008/06/13)
A photoactive compound that is the reaction product of an alkenyl azlactone compound and a nucleophilic aromatic ketone is described. Mer units derived from this compound can be used, for example, to crosslink via a hydrogen abstracting mechanism acrylic polymers in which they are incorporated.
4-ARYL- AND 4-ARYLTHIO-5-HYDROXY-2(5H)-FURANONES AS INHIBITORS OF PHOSPHOLIPASE A2
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, (2008/06/13)
The invention provides novel 5-hydroxy-4-aryl- and 5-hy-droxy-4-(arylthio)-2(5H)-furanones of the following structure: wherein R contains from about five to about twenty carbon atoms and is defined herein; X is oxygen, sulfur, S02, NH, N(lower alkyl), N(lower acyl), aminocarbonyl, carbonyl, carbonylamino, CH2 or a carbon-carbon bond; Y is hydrogen, halogen, lower alkyl, nitro, alkylthio, perfluoroalkyl, hydroxy, or lower alkoxy(C1-C8); Z is sulfur or a carbon-carbon bond; and Q is H, an alkyl of from 1-20 carbon atoms, COR', COOR', CONHR', PO(OR')2, PO(OR')R" wherein R' and R" are independently selected from the group consisting of H, an alkyl of from 1-20 carbon atoms, phenyl, and substituted phenyl and prodrugs thereof and pharmaceutically acceptable salts thereof. Pharmaceutical compositions comprising these compounds, methods of using these compounds as inhibitors of inflammation and for treating other diseases characterized by the overproduction of arachidonic acid metabolites, intermediates and methods of preparing these compounds are also provided.
PHENOLIC COMPOUNDS FROM ROOTS OF URTICA DIOICA
Kraus, Rupert,Spiteller, Gerhard
, p. 1653 - 1659 (2007/10/02)
Root extracts from Urtica dioica were separated into several classes of compounds by extraction with organic solvents at different pH values.The phenolic fraction was analysed by GC-MS after trimethylsilylation.This procedure allowed the identification of 18 phenolic compounds as well as the detection of eight lignans.The occurrence of some of these substances in this plant was previously unknown.
Fragmentation of Trimethylsilyl Derivatives of 2-Alkoxyphenols: a Further Violation of the 'Even-electron Rule'
Krauss, Dietlinde,Mainx, Hans Georg,Tauscher, Bernhard,Bischof, Peter
, p. 614 - 618 (2007/10/02)
The mass spectra of trimethylsilyl (TMS) ethers of 2-methoxyphenols show abundant +* ions originating from consecutive loss of two methyl radicals.This is illustrated by comparison of the accurate mass-measured and linked-scan spectra of the TMS derivatives of 2-methoxyphenol (guaiacol), 4-hydroxy-3-methoxybenzaldehyde (vanillin) and 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid methyl ester (ferulic acid methyl ester) with those of the TMS derivatives of phenol, 4-hydroxybenzaldehyde, 3-(4-hydroxyphenyl)-2-propenoic acid methyl ester (p-coumaric acid methyl ester), 3-methoxyphenol and 4-methoxyphenol.This distinctive ortho effect is valuable in the identification of isomeric phenolic compounds.In the spectra of the TMS derivatives of 2-ethoxyphenol and 2-propoxyphenol the sequential loss of two radicals is less pronounced, because elimination of the side-chain and methyl group with rearrengement and hydrogen migration is competitive.
