Enantioselective Construction of Tertiary α-Alkyl Fluoride via BTM-Catalyzed Fluorination of α-Alkynyl-Substituted Acetic Acids

2021 ◽  
Author(s):  
Shiru Yuan ◽  
Wen-Hua Zheng
Keyword(s):  
Acetic Acids

Junction of the Epithelium and Lamina Propria of the Bovine Rumen Mucosa

1967 ◽  
Vol 25 ◽  
pp. 68-69
Author(s):  
Al W. Stinson
Keyword(s):  
Osmium Tetroxide ◽  
Squamous Epithelium ◽  
Short Chain Fatty Acids ◽  
Chloride Ions ◽  
Fermentation Products ◽  
Ruminant Species ◽  
Protective Shield ◽  
Stratified Squamous Epithelium ◽  
Lead Hydroxide ◽  
Acetic Acids

The stratified squamous epithelium which lines the ruminal compartment of the bovine stomach performs at least three important functions. (1) The upper keratinized layer forms a protective shield against the rough, fibrous, constantly moving ingesta. (2) It is an organ of absorption since a number of substances are absorbed directly through the epithelium. These include short chain fatty acids, potassium, sodium and chloride ions, water, and many others. (3) The cells of the deeper layers metabolize butyric acid and to a lesser extent propionic and acetic acids which are the fermentation products of rumen digestion. Because of the functional characteristics, this epithelium is important in the digestive process of ruminant species which convert large quantities of rough, fibrous feed into energy.Tissue used in this study was obtained by biopsy through a rumen fistula from clinically healthy, yearling holstein steers. The animals had been fed a typical diet of hay and grain and the ruminal papillae were fully developed. The tissue was immediately immersed in 1% osmium tetroxide buffered to a pH of 7.4 and fixed for 2 hrs. The tissue blocks were embedded in Vestapol-W, sectioned with a Porter-Blum microtome with glass knives and stained with lead hydroxide. The sections were studied with an RCA EMU 3F electron microscope.

Catalytic Enantioselective Benzylation Directly from Aryl Acetic Acids

2018 ◽  
Author(s):  
Patrick Moon ◽  
Zhongyu Wie ◽  
Rylan Lundgren
Keyword(s):  
Functional Group ◽  
Terminal Event ◽  
Radical Intermediates ◽  
Carbon Carbon Bond ◽  
Or Groups ◽  
Reaction Proceeds ◽  
Wide Availability ◽  
Metal Catalyzed ◽  
The Stability ◽  
Acetic Acids

The stability and wide availability of carboxylic acids make them valuable reagents in chemical synthesis. Most transition metal catalyzed processes using carboxylic acid substrates are initiated by a decarboxylation event that generates reactive carbanion or radical intermediates. Developing enantioselective methodologies relying on these principles can be challenging, as highly reactive species tend to react indiscriminately without selectivity. Furthermore, anionic or radical intermediates generated from decarboxylation can be incompatible with protic and electrophilic functionality, or groups that undergo trapping with radicals. We demonstrate that metal-catalyzed enantioselective benzylation reactions of allylic electrophiles can occur directly from aryl acetic acids. The reaction proceeds via a pathway in which decarboxylation is the terminal event, occurring after stereoselective carbon–carbon bond formation. The mechanistic features of the process enable enantioselective benzylation without the generation of a highly basic nucleophile. Thus, the process has broad functional group compatibility that would not be possible employing established protocols.<br>

Production of lactic and acetic acids by Bacillus sp. ZM20 and Bacillus cereus following exposure to zinc oxide: A possible mechanism for Zn solubilization

Rhizosphere ◽  
2019 ◽  
Vol 12 ◽  
pp. 100170 ◽  
Author(s):  
Muhammad Zahid Mumtaz ◽  
Karen M. Barry ◽  
Anthony L. Baker ◽  
David S. Nichols ◽  
Maqshoof Ahmad ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Bacillus Cereus ◽  
Bacillus Sp ◽  
Acetic Acids

scholarly journals Production and Characterization of a Novel Gluten-Free Fermented Beverage Based on Sprouted Oat Flour

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 139
Author(s):  
Natalia Aparicio-García ◽  
Cristina Martínez-Villaluenga ◽  
Juana Frias ◽  
Elena Peñas
Keyword(s):  
Starter Culture ◽  
Microbial Quality ◽  
Pathogenic Microorganisms ◽  
Gluten Free ◽  
Good Source ◽  
Fermented Beverage ◽  
Oat Flour ◽  
Hedonic Scale ◽  
Acetic Acids

This study investigates the use of sprouted oat flour as a substrate to develop a novel gluten-free beverage by fermentation with a probiotic (Lactobacillus plantarum WCFS1) starter culture. Physicochemical, microbiological, nutritional and sensory properties of sprouted oat fermented beverage (SOFB) were characterized. After fermentation for 4 h, SOFB exhibited an acidity of 0.42 g lactic acid/100 mL, contents of lactic and acetic acids of 1.6 and 0.09 g/L, respectively, and high viable counts of probiotic starter culture (8.9 Log CFU/mL). Furthermore, SOFB was a good source of protein (1.7 g/100 mL), β-glucan (79 mg/100 mL), thiamine (676 μg/100 mL), riboflavin (28.1 μg/100 mL) and phenolic compounds (61.4 mg GAE/100 mL), and had a high antioxidant potential (164.3 mg TE/100 mL). Spoilage and pathogenic microorganisms were not detected in SOFB. The sensory attributes evaluated received scores higher than 6 in a 9-point hedonic scale, indicating that SOFB was well accepted by panelists. Storage of SOFB at 4 °C for 20 days maintained L. plantarum viability and a good microbial quality and did not substantially affect β-glucan content. SOFB fulfils current consumer demands regarding natural and wholesome plant-based foods.

2,2-Dialkylacetic Acids -A New Class of Naturally Occurring Lipid Constituents

1995 ◽  
Vol 50 (1-2) ◽  
pp. 123-126 ◽  
Author(s):  
Gottfried Raab ◽  
Jürgen Jacob
Keyword(s):  
Retention Time ◽  
Relative Retention Time ◽  
Methyl Esters ◽  
South American ◽  
Time Data ◽  
New Class ◽  
The Past ◽  
Relative Retention ◽  
Naturally Occurring ◽  
Acetic Acids

Abstract The uropygial gland waxes of the South American red-legged Seriema (Cariama cristata (L., 1766)) were found to be composed of unbranched alcohols and 2,2′-dialkyl-substituted acetic acids which so far have not been found in skin lipids. When used as a chemosystematic character, the occurrence of this lipid class separates the order Cariamiformes (Seriemas) from all other avian orders hitherto investigated, especially from the Gruiformes (cranes and rails) to which they have been tentatively attributed in the past. From the GC retention time data now available for a series of 2-alkyl-substituted fatty acid methyl esters relative retention time indices for other compounds may be predicted.

scholarly journals Characterization of Aerosol Composition, Aerosol Acidity and Organic Acid Partitioning at an Agriculture-Intensive Rural Southeastern U.S. Site

2018 ◽  
Author(s):  
Theodora Nah ◽  
Hongyu Guo ◽  
Amy P. Sullivan ◽  
Yunle Chen ◽  
David J. Tanner ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Organic Acids ◽  
Organic Acid ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Molar Concentration ◽  
Particle Phase ◽  
Aerosol Composition ◽  
Phase Water ◽  
Acetic Acids

Abstract. The implementation of stringent emission regulations has resulted in the decline of anthropogenic pollutants including sulfur dioxide (SO2), nitrogen oxides (NOx) and carbon monoxide (CO). In contrast, ammonia (NH3) emissions are largely unregulated, with emissions projected to increase in the future. We present real-time aerosol and gas measurements from a field study conducted in an agricultural-intensive region in the southeastern U.S. during the fall of 2016 to investigate how NH3 affects particle acidity and SOA formation via the gas-particle partitioning of semi-volatile organic acids. Particle water and pH were determined using the ISORROPIA-II thermodynamic model and validated by comparing predicted inorganic HNO3-NO3− and NH3-NH4+ gas-particle partitioning ratios with measured values. Our results showed that despite the high NH3 concentrations (study average 8.1 ± 5.2 ppb), PM1 were highly acidic with pH values ranging from 0.9 to 3.8, and a study-averaged pH of 2.2 ± 0.6. PM1 pH varied by approximately 1.4 units diurnally. Formic and acetic acids were the most abundant gas-phase organic acids, and oxalate was the most abundant particle-phase water-soluble organic acid anion. Measured particle-phase water-soluble organic acids were on average 6 % of the total non-refractory PM1 organic aerosol mass. The measured molar fraction of oxalic acid in the particle phase (i.e., particle-phase oxalic acid molar concentration divided by the total oxalic acid molar concentration) ranged between 47 and 90 % for PM1 pH 1.2 to 3.4. The measured oxalic acid gas-particle partitioning ratios were in good agreement with their corresponding thermodynamic predictions, calculated based on oxalic acid’s physicochemical properties, ambient temperature, particle water and pH. In contrast, gas-particle partitioning of formic and acetic acids were not well predicted for reasons currently unknown. For this study, higher NH3 concentrations relative to what has been measured in the region in previous studies had minor effects on PM1 organic acids and their influence on the overall organic aerosol and PM1 mass concentrations.

A QM/MM study combined with the theory of energy representation: Solvation free energies for anti/syn acetic acids in aqueous solution

2006 ◽  
Vol 419 (1-3) ◽  
pp. 240-244 ◽  
Author(s):  
Takumi Hori ◽  
Hideaki Takahashi ◽  
Masayoshi Nakano ◽  
Tomoshige Nitta ◽  
Weitao Yang
Keyword(s):  
Aqueous Solution ◽  
Free Energies ◽  
Solvation Free Energies ◽  
Acetic Acids
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