95975-76-1Relevant academic research and scientific papers
Synthesis of enantioenriched methyl vic-dihydroxystearates
Plate, Mark,Overs, Michael,Sch?fer, Hans J.
, p. 1255 - 1258 (1998)
Several enantioenriched methyl vic-dihydroxystearates 4 have been synthesized from methyl octadecenoates by enantioselective dihydroxylation in good yields (85-97%) and with satisfactory enantiomeric excess (ee 80-97%). The enantioenriched anti-9,10 dihydroxystearates (anti-4c) were prepared by HPLC separation of the corresponding dicamphanyl esters anti-6. Their ee was determined by HPLC of the corresponding diastereoisomeric carbamates 7, and their configuration was assigned by relation to a described compound or by applying the mnemonic device of Sharpless.
A Colorimetric Method for Quantifying Cis and Trans Alkenes Using an Indicator Displacement Assay
Valenzuela, Stephanie A.,Crory, Hannah S. N.,Yao, Chao-Yi,Howard, James R.,Saucedo, Gabriel,de Silva, A. Prasanna,Anslyn, Eric V.
supporting information, p. 13819 - 13823 (2021/05/17)
A colorimetric indicator displacement assay (IDA) amenable to high-throughput experimentation was developed to determine the percentage of cis and trans alkenes. Using 96-well plates two steps are performed: a reaction plate for dihydroxylation of the alkenes followed by an IDA screening plate consisting of an indicator and a boronic acid. The dihydroxylation generates either erythro or threo vicinal diols from cis or trans alkenes, depending upon their syn- or anti-addition mechanisms. Threo diols preferentially associate with the boronic acid due to the creation of more stable boronate esters, thus displacing the indicator to a greater extent. The generality of the protocol was demonstrated using seven sets of cis and trans alkenes. Blind mixtures of cis and trans alkenes were made, resulting in an average error of ±2 % in the percentage of cis or trans alkenes, and implementing E2 and Wittig reactions gave errors of ±3 %. Furthermore, we developed variants of the IDA for which the color may be tuned to optimize the response for the human eye.
Structural and solubility parameter correlations of gelation abilities for dihydroxylated derivatives of long-Chain, naturally occurring fatty acids
Zhang, Mohan,Selvakumar, Sermadurai,Zhang, Xinran,Sibi, Mukund P.,Weiss, Richard G.
supporting information, p. 8530 - 8543 (2015/06/02)
Creating structure-property correlations at different distance scales is one of the important challenges to the rational design of molecular gelators. Here, a series of dihydroxylated derivatives of long-chain fatty acids, derived from three naturally occurring molecules - oleic, erucic and ricinoleic acids - are investigated as gelators of a wide variety of liquids. Conclusions about what constitutes a more (or less!) efficient gelator are based upon analyses of a variety of thermal, structural, molecular modeling, and rheological results. Correlations between the manner of molecular packing in the neat solid or gel states of the gelators and Hansen solubility data from the liquids leads to the conclusion that diol stereochemistry, the number of carbon atoms separating the two hydroxyl groups, and the length of the alkanoic chains are the most important structural parameters controlling efficiency of gel formation for these gelators. Some of the diol gelators are as efficient or even more efficient than the well-known, excellent gelator, (R)-12-hydroxystearic acid; others are much worse. The ability to form extensive intermolecular H-bonding networks along the alkyl chains appears to play a key role in promoting fiber growth and, thus, gelation. In toto, the results demonstrate how the efficiency of gelation can be modulated by very small structural changes and also suggest how other structural modifications may be exploited to create efficient gelators.
Cork suberin molecular structure: Stereochemistry of the C18 epoxy and vic-diol ω-hydroxyacids and α,ω-diacids analyzed by nmr
Santos, Sara,Cabral, Vanessa,Graca, Jose
, p. 7038 - 7047 (2013/08/23)
Suberin is the biopolyester that protects the secondary tissues of plants against environmental variability and aggressions. Cork suberin is composed mostly of C18 ω-hydroxyacids and α,ω-diacids, 9,10-substituted with an unsaturation, an epoxide ring, or a vic-diol group. Although determinant for suberin macromolecular structure, the stereochemistry of these monomers is poorly studied, sometimes with contradictory results. An NMR technique was used here to assign the configuration of the 9,10-epoxy and 9,10-diol groups in C18 suberin acids, comparing the chemical shifts of diagnostic 1H and 13C signals with the ones of model compounds, before and after conversion of the vic-diol group into benzylidene acetal derivatives. The relative configuration was proved to be cis in the C18 9,10-epoxy and threo in the C18 9,10-diol suberin acids. These monomers were present in suberin probably as racemic mixtures, as shown by polarimetry. The revealed stereochemistry allows the suberin macromolecule to be built as an ordered array of midchain kinked C18 acids, reinforced by intramolecular hydrogen bonding.
Hydrolysis of Mono- and Diepoxyoctadecanoates by Alumina
Piazza, George J.,Nunz, Alberto,Foglia, Thomas A.
, p. 901 - 904 (2007/10/03)
In this study it is shown that the epoxide derivative of oleic acid, methyl 9, 10-epoxyoctadecanoate, is readily hydrolyzed to a diol when exposed to a commercial preparation of neutral alumina. Comparison of 1H and 13C NMR spectra of the diol with those of standards showed that the product was the threo isomer. When methyl 9, 10-12, 13-diepoxyoctadecanoate was treated with alumina, a mixture of dihydroxytetrahydrofuran regioisomers, methyl 9, 12-epoxy-10, 13-dihydroxystearate and methyl 10, 13-epoxy-9, 12-dihydroxystearale, was obtained. These results show that alumina is an unsuitable support for epoxidation catalysts. However, alumina-catalyzed hydrolysis of fatty epoxides is an efficient way to synthesize polyhydroxy materials, and these materials are suitable for several industrial applications.
A facile, versatile procedure for the preparation of fatty acid esters suitable for glc or hplc analyses
Grossert, J. Stuart,Ratnayake, W. M. Nimal,Swee, Tiw
, p. 2617 - 2620 (2007/10/02)
The preparation of fatty acid methyl esters for glc analyses and of various aryl esters for hplc analyses has traditionally been carried out in totally unrelated operations.This paper draws attention to the use of fatty acid-trifluoroacetic acid mixed anhydrides which may be directly and efficiently converted into either type of esters.The utility of the method was demonstrated by the preparation of series of methyl, 2-naphthyl, and vanillin fatty acid esters.The spectral characterization of some aryl fatty acid esters is recorded.
Synthesis and biological properties of some novel heterocyclic homoprostanoids
Bender,Berkoff,Groves,Sofranko,Wellman,Liu,Begosh,Horodniak
, p. 1094 - 1098 (2007/10/11)
In the search for prostaglandin like structures capable of exerting specific and desirable biological properties, a variety of simple heterocyclic homoprostanoidal derivatives was synthesized from readily available stearic acid derivatives Compounds 5b and 5e were found to be more than 100 times as potent as PGE1 and PGE2 in a tracheal chain bioassay and, like 6, 9, and 12, inhibited PGE2 induced diarrhea. Derivatives 6 and 7a showed significant PG synthetase inhibitor activity.
