Chiral catalyst

Most of the natural products isolated at present are heterocyclic compounds, so heterocyclic compounds occupy an important position in the research of organic chemistry. A compound: 13925-00-3, is researched, SMILESS is CCC1=NC=CN=C1, Molecular C6H8N2Journal, Article, Research Support, Non-U.S. Gov’t, Food Research International called Effect of roasting speed on the volatile composition of coffees with different cup quality, Author is Toci, Aline T.; Azevedo, Debora A.; Farah, Adriana, the main research direction is coffee roasting speed cup quality volatile composition; Coffee aroma; Coffee quality; Fluidized bed roaster; Phenols; Pyrazines; Roast profile; Roasting speed; Volatile compounds.Category: chiral-catalyst.

This study investigated the volatile composition of coffee blends of different cup quality, roasted in an industrial-scale semi-fluidized bed roaster (SFBR) and in a lab-scale fluidized bed roaster (FBR), at three roasting speeds/profiles, to reach medium roast degree. Thirty volatile compounds were selectively investigated. Roasting the specialty coffee blend in both roasters produced lower concentrations of total volatile compounds, compared to the low cup quality blends. Higher concentrations of pyrazines and phenols were observed in low cup quality blends. In SFBR, quality and roasting speed affected all groups of compounds, including impact compounds such as 2,5-dimethylpyrazine, 2-ethylpyrazine, 2,3-dimethylpyrazine, 2-methoxyphenol and 4-ethyl-2-methoxyphenol. In FBR, only phenols were affected. The present results help explain why different roast profiles should be used for coffees with different cup quality for better sensory outcome and why blending should be performed after roasting of green seeds. They also show that results obtained in lab scale roasters are not necessarily reproduced in industry under the same settings.

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Stasinska, B.; Danielsson, B.; Mosbach, K. published the article 《The use of biosensors in bioorganic synthesis: peptide synthesis by immobilized α-chymotrypsin assessed with an enzyme thermistor》. Keywords: peptide preparation immobilized chymotrypsin biosensor.They researched the compound: H-Leu-NH2.HCl( cas:10466-61-2 ).Name: H-Leu-NH2.HCl. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:10466-61-2) here.

Biosensor anal. of peptide synthesis in organic solvents using immobilized α-chymotrypsin is described. It is shown that with the enzyme thermistor used, a direct correlation exists between the neg. ΔT values registered and the amount of peptides formed (essentially various N-acetyldipeptide amides) allowing concentrations of 0.1 mM peptide and lower to be determined directly in the reaction medium.

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Heterocyclic compounds can be divided into two categories: alicyclic heterocycles and aromatic heterocycles. Compounds whose heterocycles in the molecular skeleton cannot reflect aromaticity are called alicyclic heterocyclic compounds. Compound: 10466-61-2, is researched, Molecular C6H15ClN2O, about Synthesis of 2-methoxy-3-isobutyl pyrazine-(methoxy-13C), the main research direction is isotope labeling methoxy isobutyl pyrazine.Application of 10466-61-2.

In recent years, stable isotope tracer technique plays an important role in metabonomics research. This work was designed through using leucine amide hydrochloride as raw material to perform cyclization reaction with glyoxal to obtain the intermediate 2-hydroxy-3-iso-Bu pyrazine, then preparing 2-chloro-3-iso-Bu pyrazine by chlorination reaction, and preparing 2-methoxy-3-iso-Bu pyrazine-(methoxy-13C) under alk. conditions by condensation reaction with isotope labeling of methanol-13C. The synthetic route could avoid the intermediate from changing from enol to keto and obtain the isomer of the target product. It had the advantages of simple operation, short process flow and less side products. The yield of target compound was more than 70%, and 13C labeled isotope abundance was not diluted The product was confirmed by HPLC, MS, 1HNMR and 13CNMR. The chem. purity was more than 99%, and the deuterium enrichment was more than 98.8 atom% 13C.

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Most of the natural products isolated at present are heterocyclic compounds, so heterocyclic compounds occupy an important position in the research of organic chemistry. A compound: 10466-61-2, is researched, SMILESS is N[C@@H](CC(C)C)C(N)=O.[H]Cl, Molecular C6H15ClN2OJournal, Article, Research Support, Non-U.S. Gov’t, International Journal of Peptide & Protein Research called Protease-catalyzed synthesis of Leu-enkephalin in a solvent-free system, Author is Klein, Jens Uwe; Cerovsky, Vaclav, the main research direction is enzymic peptide coupling leucine enkephalin; protease catalyst peptide coupling leucine enkephalin.Application of 10466-61-2.

The total enzymic synthesis of a model peptide Leu-enkephalin on a preparative scale was accomplished in the so-called solvent-free system. The syntheses were carried out in a rotary glass homogenizer by admixing solid reactants with native proteases and Na2CO3·10H2O. The most feasible way leading to biol. active Leu-enkephalin, was based on the strategy of 2 + (1 + 2) condensation catalyzed by α-chymotrypsin, thermolysin and papain for the final segment coupling. Subtilisin was used for the ester hydrolysis of peptide intermediates. Alternative strategies as well as the influence of several reaction conditions on the yield of the protease-catalyzed synthesis of Leu-enkephalin or Leu-enkephalin amide were also investigated.

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The chemical properties of alicyclic heterocycles are similar to those of the corresponding chain compounds. Compound: 4-(Hydroxymethyl)-1,3-dioxolan-2-one, is researched, Molecular C4H6O4, CAS is 931-40-8, about Kinetics modeling of glycerol carbonate synthesis from glycerol and urea over amberlyst-15 catalyst, the main research direction is glycerol carbonate urea amberlyst catalyst kinetic modeling.SDS of cas: 931-40-8.

Synthesize of glycerol carbonate from glycerol and urea is an attractive path as glycerol carbonate has a large potential as a green solvent. The aim of the present study was to develop a kinetic model of glycerol carbonate synthesis with amberlyst-15 resins as a catalyst. The investigation was carried out at various temperatures from 353 to 383 K and catalyst loading from 0.25 to 1 weight% of glycerol. The exptl. results indicated that both temperature and catalyst loading have an important effect on the glycerol conversion. According to the exptl. result, the highest glycerol conversion was found 36.90% which was obtained using a molar ratio of urea to glycerol 1:3, catalyst loading of 1 weight%, stirrer speed of 700 rpm, the temperature of 383 K and reaction time of 5 h. A kinetic model was developed based on elementary steps that take place over the catalyst. The model estimated that the pre-exponential factor was 2.89.104 mol.g-1.min-1 and the activation energy was 50.5 kJ.mol-1. By comparing the simulation and exptl. data, it could be inferred that the model could predict the trend of exptl. data well over the range of temperature and catalyst loading investigated in the present study.

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Petryaev, E. P.; Vasil’ev, G. N.; Maslovskaya, L. A.; Shadyro, O. I. published an article about the compound: 2-Chloroethyl acetate( cas:542-58-5,SMILESS:CC(OCCCl)=O ).Formula: C4H7ClO2. Aromatic heterocyclic compounds can be classified according to the number of heteroatoms or the size of the ring. The authors also want to convey more information about this compound (cas:542-58-5) through the article.

γ-Radiolysis of I (R = R1 = H) gave MeCHO, HCO2Et, C2H4, and CO2, whereas radiolysis of I (R = R1 = Me) gave only MeCHO and Me2CO. The 1st reaction proceeded via dioxolan-2-yl and -4-yl radicals; the 2nd proceeded only via the latter radical. Radiolysis of I (R = Me, R1 = H) and AcOCH2CH2Cl suggested that dioxolanyl radicals can fragment simultaneously at 2 bonds.

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Most of the natural products isolated at present are heterocyclic compounds, so heterocyclic compounds occupy an important position in the research of organic chemistry. A compound: 542-58-5, is researched, SMILESS is CC(OCCCl)=O, Molecular C4H7ClO2Journal, Article, Research Support, U.S. Gov’t, P.H.S., Journal of Biological Chemistry called Hydrolysis by acetylcholinesterase. Apparent molal volumes and trimethyl and methyl subsites, Author is Hasan, Fariza B.; Cohen, Saul G.; Cohen, Jonathan B., the main research direction is acetylcholinesterase substrate structure activity; hydrophobicity acetylcholinesterase substrate; volume molal acetylcholinesterase substrate.Computed Properties of C4H7ClO2.

A study was made of hydrolysis by acetylcholinesterase (EC 3.1.1.7) and by hydroxide of acetate esters RCH2CH2OCOCH3, where, in the following compounds, R is I, (CH3)3N+; II, (CH3)3; III, (CH3)2NH+; IV, (CH3)2CH; V, CH3NH2+; VI, CH3CH2; VII, NH3+; VIII, CH3; IX, H; X HO; XI, CH3O; XII, Cl; XIII, Br; XIV, CN. Acylation rate constants, k2, are normalized for reactivity in hydrolysis by hydroxide, k(OH). Comparison of Ks within the pairs, III and IV, V and VI, VII and VIII, and probably I and II, and the Ks for X-XIV with V and VII indicates that pos. charge makes little if any contribution to binding. I and II have similar normalized values of k2 and bimol. constants, k2(n)/Ks. IV, VI, and VIII have greater normalized values than the charged analogs III, V, and VII. The effect of pos. charge on kcat and k2 is attributed to the effect on intrinsic reactivity, k(OH). Pos. charge is not specifically activating in acylation and is absent in the very efficient deacylation. The generally accepted anionic site is better considered an uncharged trimethyl site, complementary to substrate (CH3)3X groups. A linear correlation is found between log (k2(n)/Ks) for all 14 compounds and apparent molal volume, V̅0, of the β substituents, R. Enzymic reactivity is determined predominantly by precision of fit of the β substituent in the trimethyl site and the acetyl Me in its Me site, which limits mobility of substrate and desolvates the substrate-enzyme interface.

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Quality Control of 4-Hydroxypicolinic acid. The protonation of heteroatoms in aromatic heterocycles can be divided into two categories: lone pairs of electrons are in the aromatic ring conjugated system; and lone pairs of electrons do not participate. Compound: 4-Hydroxypicolinic acid, is researched, Molecular C6H5NO3, CAS is 22468-26-4, about A hydroxypipecolic acid from thrift (Armeria maritima). Author is Fowden, L..

A hydroxypipecolic acid has been isolated from thrift and shown to be identical with a substance isolated from Acacia by Virtanen and Kari (C.A. 50, 4943e), who provisionally characterized it as 4-hydroxypipecolic acid (I). I has been synthesized by catalytic hydrogenation of 4-hydroxypicolinic acid with H and PtO. 3-Hydroxypipecolic acid was also synthesized in a like manner from 3-hydroxypicolinic acid. Oxidation of the 4- and 3-isomers yielded β-alanine, glycine, and aspartic acids and β-alanine, glycine, γ-aminobutyric, and aspartic acids, resp. Comparisons with synthetic 4- and 3-isomers indicated that the isolated imino acid may be the 3-isomer. Strictly identical behavior of natural and synthetic 3-isomer could not be demonstrated since the 2 substances differed in stereoisomeric composition

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Computed Properties of C6H8N2. So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic. Compound: 2-Ethylpyrazine, is researched, Molecular C6H8N2, CAS is 13925-00-3, about Microencapsulation of cocoa liquor nanoemulsion with whey protein using spray drying to protection of volatile compounds and antioxidant capacity.

The aim of this study was microencapsulated a nanoemulsion of cocoa liquor with whey protein by spray drying, and evaluate the effect of different inlet drying temperatures on the properties of microcapsules. The nanoemulsion showed a particle size of 202.13 nm, PdI of 0.424, and ζ-potential of -25.20 mV. The inlet drying temperature showed differences in physicochem. properties of microcapsules. Microcapsules presented good thermal stability and protection against the melting of cocoa liquor. Microcapsules obtained showed excellent yields of polyphenolic compounds (78-93%), and high retention of volatile compounds, especially of pyrazines. Greater microencapsulation yield of bioactive compounds and retention of volatile compounds was obtained at higher drying temperature (180°C). Excellent stability of polyphenols content, antioxidant capacity, and volatile compounds of cocoa liquor were observed during storage of the microcapsules at different temperature conditions, indicating the feasibility of this powder for its incorporation into functional foods.

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Most of the natural products isolated at present are heterocyclic compounds, so heterocyclic compounds occupy an important position in the research of organic chemistry. A compound: 13925-00-3, is researched, SMILESS is CCC1=NC=CN=C1, Molecular C6H8N2Journal, Article, Journal of Agricultural and Food Chemistry called Analytical determination of the severity of potato taste defect in roasted East African Arabica coffee, Author is Cain, Caitlin N.; Haughn, Noah J.; Purcell, Hayley J.; Marney, Luke C.; Synovec, Robert E.; Thoumsin, Chelsea T.; Jackels, Susan C.; Skogerboe, Kristen J., the main research direction is potato taste defect methoxypyrazine Arabica coffee microextraction GC MS; 2-isopropyl-3-methoxypyrazine; Fisher-ratio analysis; coffee; gas chromatography−mass spectrometry; potato taste defect; solid-phase microextraction.Safety of 2-Ethylpyrazine.

The quality of East African coffee beans has been significantly reduced by a flavor defect known as potato taste defect (PTD) due to the presence of 2-isopropyl-3-methoxypyrazine (IPMP) and 2-isobutyl-3-methoxypyrazine (IBMP). Therefore, the aims of this study were to determine the correlation between these methoxypyrazines and the severity of odor attributed to PTD and discover addnl. analytes that may be correlated with PTD using Fisher ratio anal., a supervised discovery-based data anal. method. Specialty ground roasted coffees from East Africa were classified as clean (i.e., no off-odor), mild, medium, or strong PTD. For the samples examined, IPMP was found to discriminate between non-defective and defective samples, while IBMP did not do so. Samples affected by PTD exhibited a wide range of IPMP concentration (1.6-529.9 ng/g). Except for one sample, the IPMP concentration in defective samples was greater than the average IPMP concentration in the non-defective samples (2.0 ng/g). Also, an anal. of variance found that IPMP concentrations were significantly different based on the severity of odor attributed to PTD (p < 0.05). Fisher ratio anal. discovered 21 addnl. analytes whose concentrations were statistically different based on the severity of PTD odor (p < 0.05). Generally, analytes that were pos. correlated with odor severity generally had unpleasant sensory descriptions, while analytes typically associated with desirable aromas were found to be neg. correlated with odor severity. These findings not only show that IPMP concentration can differentiate the severity of PTD but also that changes in the volatile analyte profile of coffee beans induced by PTD can contribute to odor severity. When you point to this article, it is believed that you are also very interested in this compound(13925-00-3)Safety of 2-Ethylpyrazine and due to space limitations, I can only present the most important information.

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