Month: April 2022

Fujii, Kiyonaga; Ikai, Yoshitomo; Mayumi, Tsuyoshi; Oka, Hisao; Suzuki, Makoto; Harada, Ken-ichi published the article 《A nonempirical method using LC/MS for determination of the absolute configuration of constituent amino acids in a peptide: elucidation of limitations of Marfey’s method and of its separation mechanism》. Keywords: absolute configuration amino acid Marfey method; fluorodinitrophenylamino acid HPLC retention absolute configuration.They researched the compound: H-Leu-NH2.HCl( cas:10466-61-2 ).Synthetic Route of C6H15ClN2O. 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.

As the first step in establishing the author’s proposed method, the advanced Marfey’s method, which is planned for the simultaneous determination of the absolute configuration of amino acids in a peptide, Marfey’s method was applied to com. available amino acids, and the separation behavior was examined in detail. Although good resolution of the diastereomeric pair of an individual amino acid was obtained for all amino acids tested and the applicability of the method was confirmed, the (1-fluoro-2,4-dinitrophenyl)-5-L-alaninamide (FDAA) derivative of the L-amino acid was not always eluted prior to its corresponding D-amino acid derivative Because this proposed method relies on the elution order of a derivatized amino acid with FDAA to determine its absolute configuration, its separation mechanism was carefully investigated using UV and NMR spectral techniques. The results suggested that the resulting conformations of the L- and D-amino acid derivatives are stable and that the resolution between the L- and D-amino acid derivatives is due to the difference in their hydrophobicity, which is derived from the cis- or trans-type arrangement of two more hydrophobic substituents at both α-carbons of an amino acid and L-alanine amide, so that the FDAA derivative of the cis (Z)-type arrangement interacts more strongly with ODS silica gel and has a longer retention time than that of the trans (E)-type arrangement. Therefore, the L-amino acid derivative is usually eluted from the column before its corresponding D-amino acid derivative in Marfey’s method. According to this separation mechanism, the elution order of a desired amino acid can be elucidated from the average retention time of the L- and D-amino acid derivatives, and the DL-serine and DL-asparagine derivatives are critical for Marfey’s method.

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Reference:
Chiral Catalysts,
Chiral catalysts – SlideShare

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.Gelas, Jacques; Petrequin, Danielle researched the compound: 2-Chloroethyl acetate( cas:542-58-5 ).Synthetic Route of C4H7ClO2.They published the article 《Cyclic acetals. XVII. Chlorination of the acetal function by 1,3,5-trichloro-1,3,5-triazine-2,4,6-dione》 about this compound( cas:542-58-5 ) in Carbohydrate Research. Keywords: chlorination cyclic acetal; triazinetrione trichloro acetal chlorination. We’ll tell you more about this compound (cas:542-58-5).

Action of 1,3,5-trichloro-1,3,5-triazine-2,4,6-trione in CCl4 containing iodine as catalyst, on 2-methyl-1,3-dioxolane gave 80% MeCO2CH2CH2Cl, 10% MeCO2CH2CHCl2 ∼1% ClCH2CO2CH2CH2Cl, and ∼1% Cl2CHCO2CH2Cl. Similar reaction with 2,2-dimethyl-1,3-dioxolane gave 65I, 20% II, 7% III, and 5% IV. These compounds are models for reactions with cyclic acetals of sugars.

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Verevkin, Sergey P.; Nagrimanov, Ruslan N.; Zaitsau, Dzmitry H.; Konnova, Maria E.; Pimerzin, Aleksey A. published an article about the compound: 2-Ethylpyrazine( cas:13925-00-3,SMILESS:CCC1=NC=CN=C1 ).Recommanded Product: 2-Ethylpyrazine. 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:13925-00-3) through the article.

This work contributes to our primary interest in applications of exptl. and computational thermochem. methods for providing the basic data required in chem.-process design. Pyrazine derivatives are considered as a seminal liquid organic hydrogen carriers. The standard molar enthalpies of vaporisation/sublimation of pyrazine derivatives were derived from the vapor pressure temperature dependences measured by the static and transpiration method. Enthalpies of fusion of the solid compounds were measured using DSC. Thermodn. data on solid-gas, liquid-gas, and solid-liquid phase transitions available in the literature were collected and combined with own exptl. results. We have evaluated and recommended the set of vaporisation and formation enthalpies of pyrazine derivatives at 298.15 K as the reliable benchmark properties for further thermochem. calculations Gas phase molar enthalpies of formation of pyrazine derivatives calculated by the high-level quantum-chem. method G4 were in agreement with the recommended exptl. data. Compilation of exptl. and theor. results derived in this work is useful for optimization of hydrogenation/dehydrogenation reactions involved in the hydrogen storage technologies.

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Reference:
Chiral Catalysts,
Chiral catalysts – SlideShare

Synthetic Route of C4H6O4. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: 4-(Hydroxymethyl)-1,3-dioxolan-2-one, is researched, Molecular C4H6O4, CAS is 931-40-8, about Application of corncob residue-derived catalyst in the transesterification of glycerol with dimethyl carbonate to synthesize glycerol carbonate. Author is Wang, Song; Wang, Jianye; Okoye, Patrick U.; Chen, Shuang; Li, Xinshu; Duan, Lin; Zhou, Huan; Li, Sanxi; Tang, Tao; Zhang, Linnan; Zhang, Ailing.

Corncob was calcined within a temperature range of 300°C to 700°C to prepare a series of corncob residue catalysts for the transesterification of glycerol with di-Me carbonate (DMC) to synthesize glycerol carbonate (GC). Among the catalysts, the corncob residue catalyst obtained through calcination of corncob at 500°C (CCR-500) showed a relatively high basicity and satisfactory catalytic activity. The structural investigation results indicated that CCR-500 was composed of carbon material and some alk. mineral salts. Using CCR-500 as the catalyst, a glycerol conversion of 98.1% and a GC yield of 94.1% were achieved when the reaction was performed at 80°C for 90 min, with a catalyst amount of 3 wt% and glycerol to DMC molar ratio of 1:3. The comparison of CCR-500 with the reported catalysts indicated that the CCR-500 was a low-cost, high-active, and easily-accessible catalyst for the transesterification of glycerol with DMC.

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Reference:
Chiral Catalysts,
Chiral catalysts – SlideShare

Computed Properties of C6H8N2. The fused heterocycle is formed by combining a benzene ring with a single heterocycle, or two or more single heterocycles. Compound: 2-Ethylpyrazine, is researched, Molecular C6H8N2, CAS is 13925-00-3, about Enrichment of white flour with spices positively impacts safety and consumer acceptance of bread. Author is Issaoui, Manel; Nesrine, Mahfoudhi; Flamini, Guido; Delgado, Amelia.

Aiming at increasing the nutritional value and sensory quality of bread, we assessed the enrichment of white flour with different levels of powd. cinnamon and pomegranate peel, through rheol., nutritional, aromatic, textural and sensory analyses. These extra ingredients were chosen for their richness in bioactive compounds, and they differently affected bread quality. In relation to raw flour, introduced ingredients slightly decreased moisture and protein content, while increasing ash, fiber and radical scavenging activity, which can be attributed to the sharing of aromatic compounds by cinnamon and pomegranate peel during the bread making process. When cinnamon was incorporated at 1%, the content of all furan derivatives was reduced up to 1/4 of initial value, 2-pentyl furan totally disappeared, and furfuryl alc. was reduced to 2.1%. Despite enriched bread’s texture was slightly worse, it was still acceptable in sensory tests, as 150 interviewed naive consumers preferred the new product over the control.

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Reference:
Chiral Catalysts,
Chiral catalysts – SlideShare

Computed Properties of C6H8N2. The mechanism of aromatic electrophilic substitution of aromatic heterocycles is consistent with that of benzene. Compound: 2-Ethylpyrazine, is researched, Molecular C6H8N2, CAS is 13925-00-3, about Formation of pyrazines in Maillard model systems: effects of structures of lysine-containing dipeptides/tripeptides. Author is Wang, Furong; Shen, Hailiang; Liu, Ting; Yang, Xi; Yang, Yali; Guo, Yurong.

At present, most investigations involving the Maillard reaction models have focused on free amino acids (FAAs), whereas the effects of peptides on volatile products are poorly understood. In our study, the formation mechanism of pyrazines, which were detected as characteristic volatiles in sunflower seed oil, from the reaction system of glucose and lysine-containing dipeptides and tripeptides was studied. The effect of the amino acid sequences of the dipeptides and tripeptides on pyrazine formation was further highlighted. Four different dipeptides and six tripeptides were selected. The results showed that the production of pyrazines in the lysine-containing dipeptide models was higher than that in the tripeptide and control models. Compounds 2,5(6)-Dimethylpyrazine and 2,3,5-trimethylpyrazine were the main pyrazine compounds in the dipeptide models. Furthermore, the C- or N-terminal amino acids of lysine-containing dipeptides can exert an important effect on the formation of pyrazines. In dipeptide models with lysine at the C-terminus, the content of total pyrazines followed the order of Arg-Lys > Hi-Lys; the order of the total pyrazine content was Lys-His > Lys-Arg in dipeptide models with N-terminal lysine. Addnl., for the tripeptide models with different amino acid sequences, more pyrazines and a greater variety of pyrazines were detected in the tripeptide models with N-terminal lysine/arginine than in the tripeptide models with N-terminal histidine. However, the total pyrazine content and the percentage of pyrazines in the total volatiles were similar in the tripeptide models with the same amino acids at the N-terminus. This study clearly illustrates the ability of dipeptides and tripeptides containing lysine, arginine and histidine to form pyrazines, improving volatile formation during sunflower seed oil processing.

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Chiral Catalysts,
Chiral catalysts – SlideShare

The three-dimensional configuration of the ester heterocycle is basically the same as that of the carbocycle. Compound: 4-(Hydroxymethyl)-1,3-dioxolan-2-one(SMILESS: O=C1OCC(CO)O1,cas:931-40-8) is researched.Synthetic Route of C6H7NO2. The article 《Reactive jojoba and castor oils-based cyclic carbonates for biobased polyhydroxyurethanes》 in relation to this compound, is published in European Polymer Journal. Let’s take a look at the latest research on this compound (cas:931-40-8).

Syntheses of novel biobased PolyHydroxyUrethane (PHU) have been performed from Jojoba and castor oil. Cyclic carbonate monomers with various functionality were synthesized from both jojoba and castor oils. Pendant cyclic carbonate groups were obtained by a two-step reaction: thiol-ene coupling with thioglycolic acid followed by esterification with glycerin carbonate. These novel cyclic carbonate monomers exhibited higher reactivity than previous intra-chain plant oil-based cyclic carbonates. Di-functional jojoba oil-based cyclic carbonate was synthesized for the first time. PHUs were obtained by aminolysis of plant oil-based cyclic carbonates with various aliphatic and aromatic diamines. Structured linear and crosslinked PHUs were obtained with Tg ranging from -45 to 20 °C. The different PHU materials were characterized by SEC, FTIR, DSC, ATG and DMA measurements. These results showed the potentiality of this environmentally friendly approach to prepare plant oils-based PHU materials with interesting performances.

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Name: H-Leu-NH2.HCl. Aromatic heterocyclic compounds can also be classified according to the number of heteroatoms contained in the heterocycle: single heteroatom, two heteroatoms, three heteroatoms and four heteroatoms. Compound: H-Leu-NH2.HCl, is researched, Molecular C6H15ClN2O, CAS is 10466-61-2, about Side reactions in enzymic peptide synthesis in organic media: effects of enzyme, solvent, and substrate concentrations. Author is Gololobov, Mikhail Yu.; Stepanov, Valentin M.; Voyushina, Tatjana L.; Morozova, Irina P.; Adlercreutz, Patrick.

The progress of enzymic peptide synthesis catalyzed by α-chymotrypsin and subtilisin from Bacillus subtilis strain 72 (subtilisin 72) in low water systems was studied. The initial reaction mixture consisted of the solvent, the acyl-group donor (Mal-Ala-Ala-Phe-OMe or Z-Ala-Ala-PheO-Me; Mal = maleyl, Z = benzyloxycarbonyl), the nucleophile H-Xaa-NH2 (Xaa = Phe, Leu, Ala), and the enzyme adsorbed on porous silica material. All amino acid residues were of the L-configuration. The solvent consisted of acetonitrile, DMF and 4% (volume/volume) of water. The DMF/acetonitrile ratio was varied between 0 and 1/1. At high concentration of the acyl-group donor, quant. formation of Mal-Ala-Ala-Phe-Xaa-NH2 or Z-Ala-Ala-Phe-Xaa-NH2 occurred. As a result, a method for the synthesis of peptide amides was developed. At low concentration of the acyl group donor and excess of the nucleophile, condensation byproducts with two and three nucleophile mols. were found in the reaction mixtures The data obtained provided evidence that organic solvents affected the S1′-specificity of α-chymotrypsin and the S1-specificity of subtilisin 72, while the S1-specificity of α-chymotrypsin and the S1′-specificity of subtilisin 72 were not affected. When the DMF content was increased, the rate of the α-chymotrypsin-catalyzed reactions decreased. In contrast to this, an increase in DMF content accelerated the subtilisin 72-catalyzed reactions. Hydrolysis of the acyl group donor did not occur in the α-chymotrypsin-catalyzed reactions. Significant (up to 50%) formation of Mal-Ala-Ala-Phe-OH was observed at the early stage of the subtilisin 72-catalyzed reactions. Later, Mal-Ala-Ala-Phe-OH underwent synthesis.

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Reference:
Chiral Catalysts,
Chiral catalysts – SlideShare

Recommanded Product: 2-Ethylpyrazine. 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 Strongly luminescent inorganic-organic hybrid semiconductors with tunable white light emissions by doping.

A series of copper bromide based inorganic-organic hybrid semiconductors have been synthesized by doping a trace amount of a secondary ligand into their parent structures. Upon near-UV excitation, these structures emit broadband bluish (“”cold””) to yellowish (“”warm””) white light. The color temperature can be systematically tuned by controlling the type and amount of the dopant. Our studies show that the observed white emission is emitted directly from the doped sample, and is not a combined effect from mixed phases. The internal quantum yields (IQYs) of these white-light-emitting hybrids are as high as 68%, which are significantly higher than those of most direct white-light-emitting phosphors reported to date. In addition, these copper halide staircase chain based hybrid structures exhibit interesting thermochromic luminescence. The high quantum efficiencies coupled with facile and low-cost synthesis and strong optical tunability of this materials group suggest its considerable promise for lighting-related applications.

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Chiral Catalysts,
Chiral catalysts – SlideShare

Synthetic Route of C6H15ClN2O. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: H-Leu-NH2.HCl, is researched, Molecular C6H15ClN2O, CAS is 10466-61-2, about Leucine and its derivatives as potential elicitors of insulin secretion in rats. Author is Warner, Victor D.; Warner, Ann M.; Vasselli, Joseph R.; Decke, Elisabeth; Pi-Sunyer, F. Xavier; Woods, Stephen C..

In rats, i.p. administration of L-leucine-HCl [760-84-9], DL-leucine-HCl [2508-63-6], and L-leucineamide-HCl [10466-61-2] increased serum levels of glucose [50-99-7] and immunoreactive insulin, while L-leucine esters had no significant effect.

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Chiral Catalysts,
Chiral catalysts – SlideShare