scholarly journals Esterifications with 2-(Trimethylsilyl)ethyl 2,2,2-Trichloroacetimidate

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 17-25
Author(s):  
Wenhong Lin ◽  
Shea T. Meyer ◽  
Shawn Dormann ◽  
John D. Chisholm
Keyword(s):  
Carboxylic Acid ◽  
High Yield ◽  
Deuterium Labeling ◽  
Ester Formation ◽  
Acid Substrate

2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate is an effective reagent for the formation of 2-trimethylsilylethyl esters without the need for an exogenous promoter or catalyst, as the carboxylic acid substrate is acidic enough to promote ester formation without an additive. A deuterium labeling study indicated that a β-silyl carbocation intermediate is involved in the transformation.

scholarly journals Esterifications with 2-(Trimethylsilyl)ethyl 2,2,2- Trichloroacetimidate

2020 ◽  
Author(s):  
Wenhong Lin ◽  
Shea T. Meyer ◽  
Shawn Dormann ◽  
John D. Chisholm
Keyword(s):  
Carboxylic Acid ◽  
High Yield ◽  
Deuterium Labeling ◽  
Ester Formation ◽  
Acid Substrate

<p>2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate is an effective reagent for the formation of 2-trimethylsilylethyl esters without the need for an exogenous promoter or catalyst, as the carboxylic acid substrate is acidic enough to promote ester formation without an additive. Deuterium labeling studies indicate that a β-silyl carbocation intermediate is involved in the transformation.</p>

scholarly journals Esterifications with 2-(Trimethylsilyl)ethyl 2,2,2- Trichloroacetimidate

2020 ◽  
Author(s):  
Wenhong Lin ◽  
Shea T. Meyer ◽  
Shawn Dormann ◽  
John D. Chisholm
Keyword(s):  
Carboxylic Acid ◽  
High Yield ◽  
Deuterium Labeling ◽  
Ester Formation ◽  
Acid Substrate

<p>2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate is an effective reagent for the formation of 2-trimethylsilylethyl esters without the need for an exogenous promoter or catalyst, as the carboxylic acid substrate is acidic enough to promote ester formation without an additive. Deuterium labeling studies indicate that a β-silyl carbocation intermediate is involved in the transformation.</p>

Functional Group Interconversion

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Carboxylic Acid ◽  
High Yield ◽  
Staudinger Ligation ◽  
University Of Alberta ◽  
University Of Tennessee ◽  
University Of British Columbia ◽  
National University ◽  
Seoul National University ◽  
Oxidative Amidation ◽  
The University

Glenn M. Samm is at the University of British Columbia reported (Angew. Chem. Int. Ed. 2012, 51, 10804) the photofluorodecarboxylation of aryloxyacids such as 1 using Selectfluor 2. Jean-François Paquin at the Université Laval found (Org. Lett. 2012, 14, 5428) that the halogenation of alcohols (e.g., 4 to 5) could be achieved with [Et2NSF2]BF4 (XtalFluor-E) in the presence of the appropriate tetraethylammonium halide. A method for the reductive bromination of carboxylic acid 6 to bromide 7 was developed (Org. Lett. 2012, 14, 4842) by Norio Sakai at the Tokyo University of Science. Professor Sakai also reported (Org. Lett. 2012, 14, 4366) a related method for the reductive coupling of acid 8 with octanethiol to produce thioether 9. The esterification of primary alcohols in water-containing solvent was achieved (Org. Lett. 2012, 14, 4910) by Michio Kurosu at the University of Tennessee Health Science Center using the reagent 11, such as in the conversion of alcohol 10 to produce 12 in high yield. Hosahudya N. Gopi discovered (Chem. Commun. 2012, 48, 7085) that the conversion of thioacid 13 to amide 14 was rapidly promoted by CuSO4. A ruthenium-catalyzed dehydrative amidation procedure using azides and alcohols, such as the reaction of 15 with phenylethanol to produce 16, was reported (Org. Lett. 2012, 14, 6028) by Soon Hyeok Hong at Seoul National University. An alternative oxidative amidation was developed (Tetrahedron Lett. 2012, 53, 6479) by Chengjian Zhu at Nanjing University and the Shanghai Institute of Organic Chemistry who utilized catalytic tetrabutylammonium iodide and disubstituted formamides to convert alcohols such as 17 to amides 18. A redox catalysis strategy was developed (Angew. Chem. Int. Ed. 2012, 51, 12036) by Brandon L. Ashfeld at Notre Dame for the triphenylphosphine-catalyzed Staudinger ligation of carboxylic acid 19 to furnish amide 20. For direct catalytic amidation of carboxylic acids and amines such as in the conversion of 21 to 23, Dennis G. Hall at the University of Alberta reported (J. Org. Chem. 2012, 77, 8386) that the boronic acid 22 was a highly effective catalyst that operated at room temperature.

scholarly journals Steryl Ester Formation and Accumulation in Steroid-Degrading Bacteria

2019 ◽  
Vol 86 (2) ◽  
Author(s):  
Johannes Holert ◽  
Kirstin Brown ◽  
Ameena Hashimi ◽  
Lindsay D. Eltis ◽  
William W. Mohn
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lipid Droplets ◽  
Steryl Ester ◽  
Biotechnological Production ◽  
Fatty Acid Substrate ◽  
Content Type ◽  
Adverse Conditions ◽  
Steryl Esters ◽  
Ester Formation ◽  
Acid Substrate

ABSTRACT Steryl esters (SEs) are important storage compounds in many eukaryotes and are often prominent components of intracellular lipid droplets. Here, we demonstrate that selected Actino- and Proteobacteria growing on sterols are also able to synthesize SEs and to sequester them in cytoplasmic lipid droplets. We found cholesteryl ester (CE) formation in members of the actinobacterial genera Rhodococcus, Mycobacterium, and Amycolatopsis, as well as several members of the proteobacterial Cellvibrionales order. CEs maximally accumulated under nitrogen-limiting conditions, suggesting that steryl ester formation plays a crucial role for storing excess energy and carbon under adverse conditions. Rhodococcus jostii RHA1 was able to synthesize phytosteryl and cholesteryl esters, the latter reaching up to 7% of its cellular dry weight and 69% of its lipid droplets. Purified lipid droplets from RHA1 contained CEs, free cholesterol, and triacylglycerols. In addition, we found formation of CEs in Mycobacterium tuberculosis when it was grown with cholesterol plus an additional fatty acid substrate. This study provides a basis for the application of bacterial whole-cell systems in the biotechnological production of SEs for use in functional foods and cosmetics. IMPORTANCE Oleaginous bacteria exhibit great potential for the production of high-value neutral lipids, such as triacylglycerols and wax esters. This study describes the formation of steryl esters (SEs) as neutral lipid storage compounds in sterol-degrading oleaginous bacteria, providing a basis for biotechnological production of SEs using bacterial systems with potential applications in the functional food, nutraceutical, and cosmetic industries. We found cholesteryl ester (CE) formation in several sterol-degrading Actino- and Proteobacteria under nitrogen-limiting conditions, suggesting an important role of this process in storing energy and carbon under adverse conditions. In addition, Mycobacterium tuberculosis grown on cholesterol accumulated CEs in the presence of an additional fatty acid substrate.

β-Carboline-3-carboxylic Acid (9H-Pyrido[3,4-b]indole-3-carboxylic Acid) and Related Compounds

1989 ◽  
Vol 42 (6) ◽  
pp. 813 ◽  
Author(s):  
JA Maclaren
Keyword(s):  
Carboxylic Acid ◽  
Rat Brain ◽  
High Yield ◽  
Brain Membranes ◽  
Novel Synthesis ◽  
Rat Brain Membranes ◽  
Related Compounds ◽  
Relative Inhibition

The synthesis of β-carboline-3-carboxylic acid and its esters (4) by oxidation of the corresponding 1,2,3,4-tetrahydro derivatives (2) or of the 3,4-dihydro derivatives (3) has been studied. A novel synthesis of the esters (3) [and hence of (4)] has been achieved in high yield by cyclization and elimination from the enamine (5). The relative inhibition of binding of a benzodiazepine to rat brain membranes by the esters (2)-(4) has been determined.

Domino transformation of isoxazoles to 2,4-dicarbonylpyrroles under Fe/Ni relay catalysis

RSC Advances ◽  
2015 ◽  
Vol 5 (24) ◽  
pp. 18172-18176 ◽  
Author(s):  
Ekaterina E. Galenko ◽  
Alexey V. Galenko ◽  
Alexander F. Khlebnikov ◽  
Mikhail S. Novikov
Keyword(s):  
Carboxylic Acid ◽  
Domino Reaction ◽  
High Yield

The domino reaction of 5-alkoxy- or 5-aminoisoxazoles, under metal relay catalysis, with symmetric 1,3-diketones gives 4-acylpyrrole-2-carboxylic acid derivatives in high yield.

Approach to the synthesis of 8-nitroquinoline-2-carboxylic acid in high yield

2016 ◽  
Vol 65 (3) ◽  
pp. 816-818
Author(s):  
S. Ya. Gadomsky ◽  
I. K. Yakuschenko
Keyword(s):  
Carboxylic Acid ◽  
High Yield

Oxygen Delignification of High-Yield Kraft Pulp. Part I: Structural Properties of Residual Lignins

Holzforschung ◽  
1999 ◽  
Vol 53 (4) ◽  
pp. 416-422 ◽  
Author(s):  
Størker T. Moe ◽  
Arthur J. Ragauskas
Keyword(s):  
Carboxylic Acid ◽  
Acid Hydrolysis ◽  
Extraction Method ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
High Yield ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Oxygen Delignification ◽  
Carboxylic Acid Groups

Summary The chemistry of oxygen delignification of high-yield kraft pulp was studied by analysis of residual lignin extracted from kraft and kraft-oxygen pulps using the acid hydrolysis/dioxane extraction method. For reference pulps cooked to kappa numbers between 20 and 25, the content of free phenolic groups decreased to about 50% the original value upon oxygen delignification, while the content of carboxylic acid groups increased by 50–100%. For lignins isolated from high-yield kraft pulp and oxygen delignified high-yield kraft pulp, it was shown that high-yield kraft pulping with polysulfide (PS) and anthraquinone (AQ) gives a residual lignin which is chemically different from that of kraft pulps cooked to lower kappa numbers. Lignin extracted from oxygen delignified high-yield PS/AQ kraft pulp was more similar to lignins extracted from kraft pulps cooked to lower kappa numbers.

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