Category: 3976-69-0

On September 30, 2021, Wang, Ting; Yang, Ke; Tian, Qing; Han, Ruiting; Zhang, Xuanshuo; Li, Aipeng; Zhang, Lianbing published an article.Formula: C5H10O3 The title of the article was Acetoacetyl-CoA reductase PhaB as an excellent anti-Prelog biocatalyst for the synthesis of chiral β-hydroxyl ester and the molecular basis of its catalytic performance. And the article contained the following:

Acetoacetyl-CoA reductase PhaB turned out to be capable of catalyzing the anti-Prelog asym. reduction of various β-ketoesters (1a-12a) and aromatic ketones (13a-29a). Particularly, PhaB showed high specific activity and excellent stereoselectivity (93.0%-99.8% eep) toward β-ketoesters. The specific activity of PhaB toward Et 4-chloroacetoacetate 11a was up to 1302.2 mU/mg. The mol. basis anal. showed the rotatable single bonds in β-ketoesters endow them with a high degree of structural flexibility and adaptability. Thus, β-ketoesters could quickly adjust their conformation and further form a productive conformation in the narrow substrate-binding pocket of the enzyme. In contrast, PhaB exhibited low specific activity and stereoselectivity toward the majority of aromatic ketones. The large steric hindrance and rigid structure resulted from aromatic rings made the aromatic ketones impossible to adjust their conformation as conveniently as β-ketoesters. Furthermore, it was found the halogen bond was the major driven force of the high specific activity of PhaB toward chlorinated β-ketoesters (10a and 11a), while the distribution of enzyme-substrate interactions was an important factor determining the enzyme activity besides the steric hindrance. Moreover, the geometric configuration of the substrate and the enzyme substrate-binding pocket played critical roles in determining the substrate binding mode and the enzyme stereoselectivity. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Formula: C5H10O3

The Article related to synechocystis phab antiprelog biocatalyst chiral beta hydroxyl ester synthesis, Placeholder for records without volume info and other aspects.Formula: C5H10O3

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Ester – an overview | ScienceDirect Topics

On June 12, 2022, Ran, Xiaoku; Dou, Deqiang; Chen, Hongyu; Ren, Guoqing published an article.Formula: C5H10O3 The title of the article was The correlations of adverse effect and tonifying effect of ginseng medicines. And the article contained the following:

Ginseng has been used for thousands of years, it is described as both a tonic for restoration of strength and a panacea. However, the adverse effect is also reported clin. In the theory of Traditional Chinese Medicine, the occurrence of adverse reactions is closely related to warm property of ginseng, which can easily lead to fireness (, in Chinese). Several presumptions indicated that fireness of ginseng may be associated with the pathophysiol. of inflammation, imbalance of metabolism, the disorder of hypothalamus-pituitary-adrenal axis, and hypothalamus-pituitary-thyroid axis. The tonifying effect of ginseng medicines was always focused on with little attention for their adverse effects. We selected red ginseng (RG), ginseng (GS), American ginseng (AG), and ginseng leaves (GL) as typical ginseng medicines to clarify correlations of adverse effect and tonifying effect of ginseng medicines. The RG, GS, AG, and GL decoctions were orally administered to rats for 30 days consecutively. The appearance indicators such as saliva secretion, urinary output, fecal moisture, heart rate were determined, and hair condition, nose color were also observed Furthermore, some biochem. indexes such as IL-6, T3, T4, TSH, ACTH, CORT, Ach, DA, EPI, NE, SP, VIP, cAMP, cGMP, AQP-5, AMPK, and the activity of SOD, GSH-PX, Na+-K+-ATPase were measured by biochem. reagent kits or ELISA (ELISA). The metabolites profile was analyzed by UPLC-QTOF-MS. Finally, the diversity of gut microbiota was also analyzed with the 16S rDNA sequencing. The study revealed the tonifying effects of ginseng medicines mainly on exciting nervous system, promoting immunity and antioxidative ability. While, the adverse effects were mainly associated with the abnormal nervous system, thyroid system, adrenal system, and oxidative stress. The GS group showed fireness symptoms, such as vertical and dirty hair, epistaxis, higher rectal temperature, lower salivary secretion, lower urinary output, lower fecal moisture. While the GL group showed the opposite symptoms. The levels of hormones, activities of the antioxidative enzyme, and Na+-K+-ATP enzyme were changed differently. From the second week to the fourth week, the levels of T3, T4, TSH, ACTH, CORT, and the activity of SOD, GSH-PX, Na+-K+-ATP enzymes were first increased, then decreased, and finally recovered to normal levels. We also found that the ginseng medicines mainly adjust the amino acid and TCA cycle metabolism exhibiting their tonifying and adverse effects. Meanwhile, GS and AG can modulate gut microbiota imbalance by increasing the gut microbial diversity as well as selectively promoting some probiotic populations, including Lactobacillus and Bifidobacterium. This is the first time to report the correlations between tonifying effects and adverse effects of four ginseng medicines. The present study demonstrated that the adverse effects of ginseng medicines mostly depended on their dosages, the higher dosage is, the more serious the adverse effects are. The adverse effects of ginseng and ginseng leaves are much more serious than red ginseng and American ginseng. The tendency of water regulation of ginseng and ginseng leaves was opposite may be related to their nature property. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Formula: C5H10O3

The Article related to ginseng medicines tonifying adverse effect, adverse effect, american ginseng, ginseng, ginseng leaves, red ginseng, tonifying effect, Placeholder for records without volume info and other aspects.Formula: C5H10O3

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Sun, Qi-An; Lu, Ze-Hai; Pu, Xiao-Qiu; Hu, Hui-Lian; Zhang, Jia-heng; Yang, Xian-Jin published an article in 2018, the title of the article was Deoxyalkoxyamination of Alcohols for the Synthesis of N-Alkoxy-N-alkylbenzenesulfonamides.Recommanded Product: 3976-69-0 And the article contains the following content:

A novel protocol for the deoxyalkoxyamination of alcs. was developed, using N-alkoxybenzenesulfonimide (NOSI) as both a sulfonyl transfer reagent and an alkoxyamine source, accessing a diverse range of N-alkoxy-N-alkylbenzenesulfonamides with excellent isolated yields. This method was characterized by metal-free reaction, scalability, and waste-balance. Chiral substrates are converted with excellent levels of stereochem. inversion. NOSI could be generated in situ during the reaction as a stable reagent if a three-component one-pot reaction was designed. Exploiting this approach to run intramol. reactions offered various N-protected isoxazolidines. In addition, valuable O-alkyl hydroxylamines (or isoxazolidines) were obtained through a neutral strategy of desulfonylation of the products. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Recommanded Product: 3976-69-0

The Article related to alkoxyalkylbenzenesulfonamide preparation alc deoxyalkoxyamination, General Organic Chemistry: Synthetic Methods and other aspects.Recommanded Product: 3976-69-0

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Ester – Wikipedia,
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On August 31, 2015, Qureshi, Zafar; Schlundt, Waldemar; Lautens, Mark published an article.Product Details of 3976-69-0 The title of the article was Introduction of Hindered Electrophiles via C-H Functionalization in a Palladium-Catalyzed Multicomponent Domino Reaction. And the article contained the following:

A general method for the incorporation of secondary alkyl iodides in a palladium-catalyzed multicomponent domino reaction is reported. With the relatively inexpensive Pd(OAc)2 as the catalyst and norbornene as a mediator, a variety of 1,2,3-trisubstituted aromatic compounds were synthesized. The reaction is scalable, producing excellent isolated yields on up to 5 mmol scale. Chiral alkyl iodides were also incorporated without any loss of stereochem. information. The developed method offers an expedient and mild C-H functionalization strategy for the synthesis of sterically congested aromatic compounds in a one-pot process. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Product Details of 3976-69-0

The Article related to trisubstituted aromatic compound preparation palladium catalyst multicomponent domino, General Organic Chemistry: Synthetic Methods and other aspects.Product Details of 3976-69-0

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Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On December 31, 2014, Osawa, Tsutomu; Kizawa, Tomoko; Ikeda, Shinji; Kitamura, Takayuki; Inoue, Yoshihisa; Borovkov, Victor published an article.SDS of cas: 3976-69-0 The title of the article was Enhanced enantioselectivity in the heterogeneous catalytic hydrogenation of acetoacetate esters into the corresponding 3-hydroxybutyrates using commercial nickel powder. And the article contained the following:

Heterogeneous catalytic hydrogenation of acetoacetic acid esters over tartaric acid/NaBr-modified Ni powder is a critical function of the steric bulk of the ester moiety to afford quant. 3-hydroxybutyrate in 94% enantiomeric excess when Et and i-Bu esters were used, providing a facile route to optically active 3-hydroxybutyrates. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).SDS of cas: 3976-69-0

The Article related to acetoacetate ester catalytic hydrogenation hydroxybutyrate enantioselectivity nickel catalyst, General Organic Chemistry: Synthetic Methods and other aspects.SDS of cas: 3976-69-0

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Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On September 30, 2013, Qiu, Haixiao; Padivitage, Nilusha L. T.; Frink, Lillian A.; Armstrong, Daniel W. published an article.COA of Formula: C5H10O3 The title of the article was Enantiomeric impurities in chiral catalysts, auxiliaries, and synthons used in enantioselective syntheses. Part 4. And the article contained the following:

The enantiomeric purity of chiral reagents used in asym. syntheses directly affects the apparent reaction selectivity and the product’s enantiomeric excess. Herein, 46 recently available chiral compounds were evaluated to determine their actual enantiomeric compositions They were not assayed previously and/or were introduced after 2006, when the last comprehensive evaluation of com. available chiral compounds is reported. These compounds are widely used in asym. syntheses as chiral synthons, catalysts, and auxiliaries. The enantioselective anal. methods include HPLC approaches using Chirobiotic, Cyclobond and LARIHC series chiral stationary phases, and GC approaches using Chiraldex chiral stationary phases. Accurate, efficient assays for selected compounds are given. All enantiomeric test results were categorized within five impurity levels (i.e., <0.01%, 0.01-0.1%, 0.1-1%, 1-10% and >10%). Different batches of the same reagent from the same company can have different levels of enantiomeric impurities. Many of the reagents tested have <0.1% enantiomeric impurities. Only one of the chiral compounds has an enantiomeric impurity exceeding 10%. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).COA of Formula: C5H10O3

The Article related to enantiomeric impurity determination chiral catalyst auxiliary synthon enantioselective synthesis, Organic Analytical Chemistry: Determinations and other aspects.COA of Formula: C5H10O3

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Takeuchi, Yuta; Kawasaki, Shun; Akagawa, Kengo; Kudo, Kazuaki published an article in 2022, the title of the article was Iterative synthesis of nitrogen-containing polyketide via oxime intermediates.Recommanded Product: 3976-69-0 And the article contains the following content:

An iterative synthesis of nitrogen-containing polyketide was reported. Chain elongation of carboxylic acid via decarboxylative Claisen condensation with malonic acid half thioester was iteratively performed to construct carbon frameworks. β-Keto groups formed by the chain elongation were appropriately converted to O-Me oximes for incorporation of nitrogen atoms. Cyclization of the resulting oxime intermediates followed by reductive N-O cleavage afforded structurally diversed nitrogen-containing polyketides such as 2-pyridone, 4-aminopyrone, and 4-aminosalicylate. This method was finally applied to the synthesis of (R)-6-aminomellein, which was a nitrogen-substituted derivative of bioactive compound, (R)-6-methoxymellein. The versatility of the present method would enable the synthesis of diverse polyketides with nitrogen functional groups, which could be potentially utilized for the development of novel bioactive compounds The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Recommanded Product: 3976-69-0

The Article related to malonic thioester carboxylic acid decarboxylative claisen condensation, nitrogen polyketide preparation, General Organic Chemistry: Synthetic Methods and other aspects.Recommanded Product: 3976-69-0

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Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

Zhao, Qichao; Twu, Pamela; Anderson, Jared L. published an article in 2012, the title of the article was A rapid analytical method for monitoring the enantiomeric purity of chiral molecules synthesized in ionic liquid solvents.Category: esters-buliding-blocks And the article contains the following content:

Ionic liquids (ILs) were widely used as reaction solvents in asym. synthesis due to their interesting phys. and chem. properties. However, monitoring reactant-to-product conversion and the enantiopurity of formed stereoisomers often involves a tedious extraction step before chromatog. anal. A rapid and sensitive sampling method using headspace solid-phase microextraction (SPME) coupled to chiral gas chromatog. was developed for the online anal. of chiral mols. in the IL solvent. Three different SPME sorbent coatings, polydimethylsiloxane, polyacrylate, and a polymeric ionic liquid-based fiber, were examined The anal. performance of the developed method was evaluated in terms of reproducibility, slope of calibration curve, linear range, calibration linearity, and the determination of detection limits. The SPME method was successfully applied in the determination of enantiomeric excess from selected mixtures of chiral mols. A preliminary study was performed using an on-fiber derivatization approach revealing that the stereoisomers extracted by the SPME fiber can be efficiently derivatized using a short on-fiber derivatization step. The developed SPME method eliminates the need of sequestering the reaction, separating the compounds of interest from the IL solvent, and the addition of a derivatizing reagent. Chirality, 2012. © 2012 Wiley Periodicals, Inc. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Category: esters-buliding-blocks

The Article related to enantiomeric purity monitoring chiral mol synthesis ionic liquid solvent, headspace solid phase microextraction gc enantiomeric purity monitoring, Organic Analytical Chemistry: Determinations and other aspects.Category: esters-buliding-blocks

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics

On February 29, 2012, Siedler, Solvej; Bringer, Stephanie; Blank, Lars M.; Bott, Michael published an article.Safety of (R)-Methyl 3-hydroxybutanoate The title of the article was Engineering yield and rate of reductive biotransformation in Escherichia coli by partial cyclization of the pentose phosphate pathway and PTS-independent glucose transport. And the article contained the following:

Optimization of yields and productivities in reductive whole-cell biotransformations is an important issue for the industrial application of such processes. In a recent study with Escherichia coli, we analyzed the reduction of the prochiral β-ketoester Me acetoacetate by an R-specific alc. dehydrogenase (ADH) to the chiral hydroxy ester (R)-Me 3-hydroxybutyrate (MHB) using glucose as substrate for the generation of NADPH. Deletion of the phosphofructokinase gene pfkA almost doubled the yield to 4.8 mol MHB per mol of glucose, and it was assumed that this effect was due to a partial cyclization of the pentose phosphate pathway (PPP). Here, this partial cyclization was confirmed by 13C metabolic flux anal., which revealed a neg. net flux from glucose 6-phosphate to fructose 6-phosphate catalyzed by phosphoglucose isomerase. For further process optimization, the genes encoding the glucose facilitator (glf) and glucokinase (glk) of Zymomonas mobilis were overexpressed in recombinant E. coli strains carrying ADH and deletions of either pgi (phosphoglucose isomerase), or pfkA, or pfkA plus pfkB. In all cases, the glucose uptake rate was increased (30-47%), and for strains Δpgi and ΔpfkA also, the specific MHB production rate was increased by 15% and 20%, resp. The yield of the latter two strains slightly dropped by 11% and 6%, but was still 73% and 132% higher compared to the reference strain with intact pgi and pfkA genes and expressing glf and glk. Thus, metabolic engineering strategies are presented for improving yield and rate of reductive redox biocatalysis by partial cyclization of the PPP and by increasing glucose uptake, resp. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Safety of (R)-Methyl 3-hydroxybutanoate

The Article related to metabolic engineering escherichia partial cyclization pentose phosphate pathway glucose, Fermentation and Bioindustrial Chemistry: Other and other aspects.Safety of (R)-Methyl 3-hydroxybutanoate

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On December 5, 2014, Szczesniak, Piotr; Pazdzierniok-Holewa, Agnieszka; Klimczak, Urszula; Stecko, Sebastian published an article.SDS of cas: 3976-69-0 The title of the article was Synthesis of β- and γ-Hydroxy α-Amino Acids via Enzymatic Kinetic Resolution and Cyanate-to-Isocyanate Rearrangement. And the article contained the following:

A new strategy for stereoselective preparation of all four isomers of β- and γ-hydroxy α-amino acids is presented. The developed procedure is based on enzymic kinetic resolution and cyanate-to-isocyanate rearrangement as key steps. Stereocontrol is achieved by proper choice of the starting hydroxy acid, the course of kinetic resolution, and the stereospecific sigmatropic rearrangement step, which proceeds with full chirality transfer. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).SDS of cas: 3976-69-0

The Article related to hydroxy amino acid stereoselective preparation enzymic kinetic resolution rearrangement, Amino Acids, Peptides, and Proteins: Amino Acids and other aspects.SDS of cas: 3976-69-0

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics