691-83-8Relevant articles and documents
Leveraging the n→π* Interaction in Alkene Isomerization by Selective Energy Transfer Catalysis
Brüss, Linda,Daniliuc, Constantin G.,Gilmour, Ryan,McLaughlin, Calum,Molloy, John J.,Nevesely, Tomá?
supporting information, (2021/11/30)
Examples of geometric alkene isomerization in nature are often limited to the net exergonic direction (ΔG°0) comparatively under-represented. Inspired by the expansiveness of the maleate to fumarate (Z→E) isomerization in biochemistry, we investigated the inverse E→Z variant to validate nO→πC=O* interactions as a driving force for contra-thermodynamic isomerization. A general protocol involving selective energy transfer catalysis with inexpensive thioxanthone as a sensitizer (λmax=402 nm) is disclosed. Whilst in the enzymatic process nO→πC=O* interactions commonly manifest themselves in the substrate, these same interactions are shown to underpin directionality in the antipodal reaction by shortening the product alkene chromophore. The process was validated with diverse fumarate derivatives (>30 examples, up to Z:E>99:1), including the first examples of tetrasubstituted alkenes, and the involvement of nO→πC=O* interactions was confirmed by X-ray crystallography.
FRAGRANCE MIXTURE
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Paragraph 0317; 0322-0327, (2020/01/24)
A fragrance mixture and its applications, in particular perfume oils, cosmetic agents, application agents or washing and cleaning agents, containing a sensory effective amount of (i) (E)-2-methyl-but-2-endicarboxylic acid diethyl ester, (ii) (Z)-2-methyl-but-2-endicarboxylic acid diethyl ester or (iii) 2-methylenebutanedicarboxylic acid diethyl ester and mixtures thereof and analogous esters derived from these compounds and mixtures.
Steric effects on the stereochemistry of old yellow enzyme-mediated reductions of unsaturated diesters: Flipping of the substrate within the enzyme active site induced by structural modifications
Brenna, Elisabetta,Gatti, Francesco G.,Manfredi, Alessia,Monti, Daniela,Parmeggiani, Fabio
supporting information, p. 2859 - 2864 (2013/01/15)
The ene-reductase-mediated reduction of the carbon-carbon double bond of some alkyl 2- substituted butenedioates was investigated. The stereochemical outcome of the reaction was found to be influenced by steric effects. Ethyl and butyl citraconates were converted into the corresponding alkyl (R)-2-methylsuccinates with excellent enantioselectivity, whereas ethyl and butyl mesaconates were completely unreactive. Methyl 2-substituted fumarates were reduced to enantiomerically enriched methyl (S)-2-substituted succinates, whereas the (Z)-stereoisomers were left unreacted by enereductases. Labelling experiments were performed to investigate the mechanism of these bioreductions and explain their stereochemical outcome.
Exploration of the molecular origin of the azinomycin epoxide: Timing of the biosynthesis revealed
Sharma, Vasudha,Kelly, Gilbert T.,Watanabe, Coran M. H.
supporting information; experimental part, p. 4815 - 4818 (2009/05/31)
(Equation Presented) Streptomyces sahachiroi whole cell feeding experiments, utilizing putative precursors labeled with stable isotopes, established that the epoxide unit of the DNA cross-linked agents, azinomycin A and B, proceeds via a valine-dependent pathway and that hydroxylation and dehydration precedes formation of the terminal epoxide. Sodium 3-methyl-2-oxobutenoate, formed through a transimination reaction, was shown to be the penultimate precursor incorporated into the azinomycin epoxide.
Acylphosphonates as Substrates for Wittig and Horner-Wittig Reactions. Unusual Stereoselectivity in the Synthesis of β-Phosphinoylacrylates
Harris, Roger L. N.,McFadden, Helen G.
, p. 417 - 424 (2007/10/02)
Phosphorus-stabilized carbanions with additional stabilizing groups react with dialkyl acylphosphonates (alkanoyl- and aroyl-phosphonates) to give fair to good yields of dialkyl vinylphoshponates, with some limitations imposed by competing side reactions
FACILE ESTERIFICATION OF CARBOXYLIC ACIDS WITH ORGANOPHOSPHORUS REAGENTS. NOVEL APPLICATION OF ALKYLPHOSPHORIC ESTERS (APE)
Balasubramaniyan, V.,Bhatia, V. G.,Wagh, S. B.
, p. 1475 - 1485 (2007/10/02)
A mixture of alkyl phosphate esters (APE) obtained from P4O10 and alkanols taken in 1:6 mole ratio is an excellent esterification reagent for several classes of carboxylic acids.This new reagent offers several advantages compared to conventional reagents.
NEW YLIDE ANIONS. A VINYL ANION EQUIVALENT FOR SUBSTITUTED FUMARATE ESTERS
Cooke, Manning P.
, p. 381 - 384 (2007/10/02)
A new type of ylide anion is reported which upon alkylation and elimination of triphenylphosphine serves as a vinyl anion equivalent.
The Reactions of Lignin with Alkaline Hydrogen Peroxide. Part IV. Products from the Oxidation of Quinone Model Compounds
Gellerstedt, Goeran,Hardell, Hanne-Lise,Lindfors, Eva-Lisa
, p. 669 - 674 (2007/10/02)
Simple para- and orhto-quinoid structures related to lignin have been oxidized with hydrogen peroxide under mild alkaline conditions.Most of the reaction products, i.e. carboxylic acids formed by oxidative cleavage of the quinoid ring together with acids formed by more extensive degradation of the starting materials, were identified after conversion into esters.In addition, small amounts of hydroxylated quinones were found.Mechanisms for the formation of these products are suggested and the significance of the results for the bleaching of mechanical pulps with hydrogen peroxide is briefly discussed.
