Tag: 100-200

On May 25, 2020, Abdelkawy, Mahmoud A.; Aly, El-Saied A.; El-Badawi, Mahmoud A.; Itsuno, Shinichi published an article.Name: Methyl 2-cyclopentanonecarboxylate The title of the article was Synthesis of Cinchona Urea Polymers and Their Evaluation as Catalyst in the Asymmetric Reactions. And the article contained the following:

Chiral polyureas of cinchona alkaloids were synthesized via repetitive Mizoroki-Heck (MH) coupling reaction. The Pd-catalyzed polycondensation of cinchona urea dimers and 1,4-diiodobenzene afforded the chiral polyureas. The catalytic activity of the chiral polymers was subsequently investigated. The asym. Michael addition of ketoesters such as Me 2-oxocyclopentanecarboxylate, acetylacetone to nitroolefins (E)-ArCH=CHNO2 (Ar = Ph, 4-methylphenyl, 4-fluorophenyl, thiophen-2-yl) was successfully catalyzed by the polymeric organocatalysts to give the corresponding Michael adducts I and with 3-[(1S)-2-nitro-1-phenylethyl]pentane-2,4-dione high catalytic activities and excellent enantioselectivities (up to >99% ee). The polymeric catalysts were insoluble in commonly used organic solvents. They were easily recovered and reused several times without any loss of the catalytic activity. The experimental process involved the reaction of Methyl 2-cyclopentanonecarboxylate(cas: 10472-24-9).Name: Methyl 2-cyclopentanonecarboxylate

The Article related to polyurea cinchona alkaloid preparation, cinchona urea dimer diiodobenzene mizoroki heck polycondensation palladium catalyst, ketoester nitroolefin asym michael addition polyurea cinchona alkaloid catalyst and other aspects.Name: Methyl 2-cyclopentanonecarboxylate

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

Siedler, Solvej; Bringer, Stephanie; Polen, Tino; Bott, Michael published an article in 2014, the title of the article was NADPH-dependent reductive biotransformation with Escherichia coli and its pfkA deletion mutant: Influence on global gene expression and role of oxygen supply.Application of 3976-69-0 And the article contains the following content:

An Escherichia coli ΔpfkA mutant lacking the major phosphofructokinase possesses a partially cyclized pentose phosphate pathway leading to an increased NADPH per glucose ratio. This effect decreases the amount of glucose required for NADPH regeneration in reductive biotransformations, such as the conversion of Me acetoacetate (MAA) to (R)-Me 3-hydroxybutyrate (MHB) by an alc. dehydrogenase from Lactobacillus brevis. Here, global transcriptional analyses were performed to study regulatory responses during reductive biotransformation. DNA microarray anal. revealed amongst other things increased expression of soxS, supporting previous results indicating that a high NADPH demand contributes to the activation of SoxR, the transcriptional activator of soxS. Furthermore, several target genes of the ArcAB two-component system showed a lower mRNA level in the reference strain than in the ΔpfkA mutant, pointing to an increased QH2/Q ratio in the reference strain. This prompted us to analyze yields and productivities of MAA reduction to MHB under different oxygen regimes in a bioreactor. Under anaerobic conditions, the specific MHB production rates of both strains were comparable (7.4 ± 0.2 mmolMHB h-1 gcdw-1) and lower than under conditions of 15% dissolved oxygen, where those of the reference strain (12.8 mmol h-1 gcdw-1) and of the ΔpfkA mutant (11.0 mmol h-1 gcdw-1) were 73% and 49% higher. While the oxygen transfer rate (OTR) of the reference strain increased after the addition of MAA, presumably due to the oxidation of the acetate accumulated before MAA addition, the OTR of the ΔpfkA strain strongly decreased, indicating a very low respiration rate despite sufficient oxygen supply. The latter effect can likely be attributed to a restricted conversion of NADPH into NADH via the soluble transhydrogenase SthA, as the enzyme is outcompeted in the presence of MAA by the recombinant NADPH-dependent alc. dehydrogenase. The differences in respiration rates can explain the suggested higher ArcAB activity in the reference strain. Biotechnol. Bioeng. 2014;9999: 1-9. © 2014 Wiley Periodicals, Inc. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Application of 3976-69-0

The Article related to escherichia reductive biotransformation oxygen supply gene expression, dna microarrays, escherichia coli, stha transhydrogenase, phosphofructokinase, reductive whole-cell biotransformation, resting cells and other aspects.Application of 3976-69-0

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

On December 15, 2021, He, Fei; Duan, Jiawen; Zhao, Jiwen; Li, Hehe; Sun, Jinyuan; Huang, Mingquan; Sun, Baoguo published an article.Product Details of 123-25-1 The title of the article was Different distillation stages Baijiu classification by temperature-programmed headspace-gas chromatography-ion mobility spectrometry and gas chromatography-olfactometry-mass spectrometry combined with chemometric strategies. And the article contained the following:

Liquid-liquid microextraction (LLME) combined with gas chromatog.-olfactometry-mass spectrometry (GC-O-MS) was used to detect the variations in volatile compounds during the distillation process (head, heart, and tail) of raw Baijiu produced by different layers of fermented grains; 47 aroma compounds were sniffed and identified. Moreover, temperature-programmed headspace gas chromatog.-ion mobility spectrometry (TP-HS-GC-IMS) was applied to characterize the Baijiu distillation process for the first time. The 3D fingerprint spectrum clearly showed a variation in volatile compounds from different distillation stages, and most compounds showed a downward trend. In addition, multivariate statistical anal., including principal component anal. (PCA), partial least squares discriminant anal. (PLS-DA), etc., confirmed ten aroma active markers related to classification, indicating that these markers had a great influence on the flavor of raw Baijiu. The experimental process involved the reaction of Diethyl succinate(cas: 123-25-1).Product Details of 123-25-1

The Article related to distillation baijiu temperature headspace gas chromatog ion mobility spectrometry, aroma-active compounds, multivariate statistical analysis, raw baijiu classification, strong flavor baijiu, tp-hs-gc–ims and other aspects.Product Details of 123-25-1

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

Niedbala, Patryk; Majdecki, Maciej; Grodek, Piotr; Jurczak, Janusz published an article in 2022, the title of the article was H-Bond Mediated Phase-Transfer Catalysis: Enantioselective Generating of Quaternary Stereogenic Centers in β-Keto Esters.COA of Formula: C7H10O3 And the article contains the following content:

In this work, the development of a highly optimized method for generating the quaternary stereogenic centers in β-keto esters I (R = Me, i-Pr, t-Bu; R1 = H, 2-Me, 3-Me, 4-Me, 4-Cl; R2 = R3 = H; R2R3 = -CH=CH-CH=CH-) was presented. This enantioselective phase-transfer alkylation catalyzed by hybrid Cinchona catalysts II (R4 = naphthalen-2-yl, naphthalen-1-yl, quinolin-8-yl) allows for the efficient generation of the optically active products I with excellent enantioselectivity, using only 1 mol% of the catalyst. The vast majority of phase-transfer catalysts in asym. synthesis work is made by creating ionic pairs with the nucleophile-attacking anionic substrate. Therefore, it is a sensible approach to search for new methodologies capable of introducing functional groups into the precursor’s structure, maintaining high yields and enantiomeric purity. The experimental process involved the reaction of Methyl 2-cyclopentanonecarboxylate(cas: 10472-24-9).COA of Formula: C7H10O3

The Article related to benzyl keto ester preparation enantioselective, keto ester benzyl bromide alkylation phase transfer catalyst, cinchona catalysts, alkylation, enantioselectivity, organocatalysis, phase-transfer catalysis and other aspects.COA of Formula: C7H10O3

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

On April 30, 2022, Yu, Haiyan; Zheng, Danwei; Xie, Tong; Xie, Jingru; Tian, Huaixiang; Ai, Lianzhong; Chen, Chen published an article.Name: Diethyl succinate The title of the article was Comprehensive two-dimensional gas chromatography mass spectrometry-based untargeted metabolomics to clarify the dynamic variations in the volatile composition of Huangjiu of different ages. And the article contained the following:

Aging plays an important role in the formation of aroma characteristics of Huangjiu, a traditional Chinese alc. beverage. Comprehensive two-dimensional gas chromatog. mass spectrometry (GCxGC-qMS)-based untargeted metabolomics combined with a multivariate anal. was used to investigate the dynamic variations in the aroma profile of Huangjiu during aging process and to establish the relationship between the changing volatile metabolite profiles and the age-dependent sensory attributes. A total of 144 volatile metabolites were identified by GCxGC-qMS and 63 were selected as critical metabolites based on variable importance in projection values and p-values. Based on the results of principal component anal., orthogonal partial least-squares discriminant anal., and hierarchical clustering anal., the samples of six different ages were divided into three groups: 1Y and 3Y samples, 5Y and 8Y samples, and 10Y and 15Y samples. The partial least-squares anal. results further revealed the relationship between the aromas attributes and variations of these volatile compounds The high esters, aldehydes, and lactones contents contributed to the high intensities of the sweet and ester aroma attributes of the aged Huangjiu, while the high alcs. and Et esters contents contributed to the alc. and fruity aroma attributes of the newly brewed Huangjiu. These results improve our understanding of the chem. nature of the aroma characteristics of aged Huangjiu. Huangjiu is often labeled with its age as a measure of quality, which influences consumers’ choice. Dynamic variations in volatile compounds of Huangjiu during aging and its contribution to the aroma characteristics of Huangjiu were figured out, which will assist the industry to produce better quality aged Huangjiu for consumers. The experimental process involved the reaction of Diethyl succinate(cas: 123-25-1).Name: Diethyl succinate

The Article related to metabolome gas chromatog mass spectrometry dynamic variation volatile, huangjiu aging, aroma attributes, comprehensive two-dimensional gas chromatography mass spectrometry, untargeted metabolomics, volatile compounds and other aspects.Name: Diethyl succinate

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

On January 31, 2019, Bityukov, Oleg V.; Vil’, Vera A.; Lukashin, Nikita V.; Cherednichenko, Aleksandr G.; Nikishin, Gennady I.; Terent’ev, Alexander O. published an article.Product Details of 517-23-7 The title of the article was Solvent-free silica gel mediated decarboxylation of C-O coupling products of β-diketones and β-oxo esters with malonyl peroxides. And the article contained the following:

Silica gel was found to mediate decarboxylation of tetracarbonyl compounds with a free carboxylic group prepared from β-dicarbonyl compounds and malonyl peroxides to give I [R1 = Me; R2 = Me, CH2Ph, (CH2)2C(O)CH3, etc.; R1R2 = (CH2)3, (CH2)4, O(CH2)2; R3 = Me, OEt; R4 = CHEt2, CH(n-Bu)2, c-C4H7, c-C5H9]. Under solvent-free heterogeneous conditions silica gel effectively acts as a mediator of C-O coupling with further decarboxylation at 120 °C. The experimental process involved the reaction of 3-Acetyldihydrofuran-2(3H)-one(cas: 517-23-7).Product Details of 517-23-7

The Article related to acyloxy dicarbonyl compound preparation solventless, oxoester malonyl peroxide decarboxylation oxidative coupling silica gel catalyst, diketone malonyl peroxide decarboxylation oxidative coupling silica gel catalyst and other aspects.Product Details of 517-23-7

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

On October 31, 2022, Zhang, Yan-Zeng; Lin, Xiang-Na; Ji, Yan-Qing; He, Hong-Jun; Yang, Hong-Zhuan; Tang, Xiao-Juan; Liu, Yun-Guo published an article.Recommanded Product: 123-25-1 The title of the article was Characterization and correlation of dominant bacteria and volatile compounds in post-fermentation process of Ba-bao Douchi. And the article contained the following:

Ba-bao Douchi, traditionally produced and spontaneously fermented for 1-2 years, has a unique flavor. However, little information is known about microorganisms and volatile flavors, particularly their relationship. In this study, the aroma profiles including the key aroma compounds, and bacterial communities were characterized and the correlations between dominant bacterial genera with key aroma compounds were studied during the post-fermentation of Ba-bao Douchi. The research showed that 12 bacterial genera were identified as the dominant genus by high-throughput sequencing. A total of 84 volatile compounds were detected by HS-GC-IMS and HS-SPME-GC-MS. Odor activity value (OAV) and gas chromatog.-Mass spectrometry-olfactometry (GC-MS-O) were combined to determine the key volatile compounds, and the main volatile compounds including Et hexanoate, Et heptanoate, isovaleraldehyde, (+)-α-pinene, beta-phellandrene, were found to be responsible for the strong fruitiness, chocolate fragrance, fresh scent flavor, and ginger flavor of Ba-bao Douchi. Pearson correlation anal. showed that 5 dominant bacterial genera were pos. associated with > 6 key volatile compounds (p < 0.01, |r| > 0.7). Thus, these bacterial genera might have an effect on the biosynthesis of volatile components. This study provides a theor. reference for revealing the functional microorganisms and improving the flavor quality of Ba-bao Douchi. The experimental process involved the reaction of Diethyl succinate(cas: 123-25-1).Recommanded Product: 123-25-1

The Article related to ba bao douchi volatile compound isovaleraldehyde hexanoate beta phellandrene, ba-bao douchi, correlation analysis, dominant bacterial genera, key volatile compounds, spontaneous post-fermentation, volatile compounds and other aspects.Recommanded Product: 123-25-1

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

On January 13, 2014, Klitzke, Joice S.; Roisnel, Thierry; Kirillov, Evgeny; de L. Casagrande, Osvaldo Jr.; Carpentier, Jean-Francois published an article.Product Details of 3976-69-0 The title of the article was Yttrium- and Aluminum-Bis(phenolate)pyridine Complexes: Catalysts and Model Compounds of the Intermediates for the Stereoselective Ring-Opening Polymerization of Racemic Lactide and β-Butyrolactone. And the article contained the following:

Yttrium and aluminum complexes of an original pyridine-bis-(phenolate) ligand were prepared Reactions of {ONOMe,Cumyl}-Y-[N-(SiHMe2)2](THF)(Et2O) (1) with 1 equiv of Me-(R)-3-hydroxybutyrate and Me (S,S)-lactyllactate afforded resp. {ONOMe,Cumyl}-Y-((R)-OCH-Me-CH2COOMe) (2) and {ONOMe,Cumyl}-Y-((S,S)-OCH-Me-CO2CH-Me-CO2Me) (3), which are rare models of the active species in the ring-opening polymerization (ROP) of β-butyrolactone (BBL) and lactide (LA), resp. 13C NMR data for 2 and 3 indicate that, in solution, the carbonyl groups coordinate onto the yttrium centers, forming mononuclear species with six- and five-membered cycles, resp. The aluminum compounds {ONOMe,Cumyl}-Al-(iPr-(S)-lactate) (5), {ONOMe,Cumyl}-Al-((R)-OCH-Me-CH2COOCH3) (6), and {ONOMe,Cumyl}-Al-((rac)-OCH-(CF3)-CH2CO2C2H5) (7) were prepared analogously from the parent Me complex {ONOMe,Cumyl}-AlMe (4). NMR data and the solid-state structure of 6 confirm the coordination of the carbonyl group. Yttrium compounds 1 and 2 are active initiators for the ROP of racemic LA and BBL. Their performances (activity, control of the mol. weights, tacticity) are much affected by the nature of the solvent or by the addition of just a few equivalent of pyridine. Optimal conditions are quite contrasted for the ROP of rac-LA and rac-BBL, highlighting fundamental differences between these two monomers. In the best cases, highly heterotactic PLAs (Pr up to 0.96) and syndiotactic-enriched PHB (Pr up to 0.86), with good control over the mol. weights, were obtained. 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 yttrium aluminum pyridinebisphenolato hydroxybutyrate lactyllactate complex preparation crystal structure, lactide butyrolactone polymerization yttrium aluminum pyridinebisphenolato hydroxybutyrate complex catalyst and other aspects.Product Details of 3976-69-0

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

On December 31, 2019, Rao, Jingxin; Zhang, Rongzhen; Liang, Hongbo; Gao, Xiao-Dong; Nakanishi, Hideki; Xu, Yan published an article.Electric Literature of 3976-69-0 The title of the article was Efficient chiral synthesis by Saccharomyces cerevisiae spore encapsulation of Candida parapsilosis Glu228Ser/(S)-carbonyl reductase II and Bacillus sp. YX-1 glucose dehydrogenase in organic solvents. And the article contained the following:

Background: Saccharomyces cerevisiae AN120 osw2Δ spores were used as a host with good resistance to unfavorable environment. This work was undertaken to develop a new yeast spore-encapsulation of Candida parapsilosis Glu228Ser/(S)-carbonyl reductase II and Bacillus sp. YX-1 glucose dehydrogenase for efficient chiral synthesis in organic solvents. Results: The spore microencapsulation of E228S/SCR II and GDH in S. cerevisiae AN120 osw2Δ catalyzed (R)-phenylethanol in a good yield with an excellent enantioselectivity (up to 99%) within 4 h. It presented good resistance and catalytic functions under extreme temperature and pH conditions. The encapsulation produced several chiral products with over 70% yield and over 99% enantioselectivity in Et acetate after being recycled for 4-6 times. It increased substrate concentration over threefold and reduced the reaction time two to threefolds compared to the recombinant Escherichia coli containing E228S and glucose dehydrogenase. Conclusions: This work first described sustainable enantioselective synthesis without exogenous cofactors in organic solvents using yeast spore-microencapsulation of coupled alc. dehydrogenases.[Figure not available: see fulltext.]. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Electric Literature of 3976-69-0

The Article related to saccharomyces candida bacillus spore encapsulation carbonyl reductase gdh solvent, (s)-carbonyl reductase ii, glucose dehydrogenase, organic solvent, spore-microencapsulation, sustainable enantioselective catalysis and other aspects.Electric Literature of 3976-69-0

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

On September 13, 2017, Sargent, Brendon T.; Alexanian, Erik J. published an article.Recommanded Product: (R)-Methyl 3-hydroxybutanoate The title of the article was Cobalt-Catalyzed Carbonylative Cross-Coupling of Alkyl Tosylates and Dienes: Stereospecific Synthesis of Dienones at Low Pressure. And the article contained the following:

Nonracemic dienones such as I were prepared diastereoselectively and enantiospecifically in 38-82% yields and in 93:7-98.5:1.5 enantiospecificities by coupling of secondary alkyl tosylates such as II with 1,3-dienes such as (E)-PhCH:CHCH:CH2 in the presence of KCo(CO)4 and 2,2,6,6-tetramethylpiperidine in tert-amyl alc. under 2 atm. of CO pressure. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Recommanded Product: (R)-Methyl 3-hydroxybutanoate

The Article related to dienone nonracemic diastereoselective preparation, cobalt catalyst stereoselective carbonylation coupling secondary alkyl tosylate diene, enantiospecific carbonylative cross coupling secondary alkyl tosylate diene and other aspects.Recommanded Product: (R)-Methyl 3-hydroxybutanoate

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