Month: November 2022

Xu, Sihang published the artcileIdentification of alkylpyrazines by gas chromatography mass spectrometry (GC-MS), Safety of 2,3,5-Trimethylpyrazine, the main research area is alkylpyrazine gas chromatog mass spectrometry; Gas chromatography; Mass spectrometry; Pyrazines; Retention indices; Stationary phases.

Pyrazines are an important group of natural products widely used as food additives and fragrants. Gas chromatog.-mass spectrometry (GC-MS) is the most widely applied anal. technique for characterization of alkylpyrazines. However, mass spectra of many positional isomers of alkylpyrazines are very similar. Consequently, an unambiguous identification of each positional isomer by spectral interpretation or database search protocols is practically unfeasible. In fact, there are many misidentifications in literature. To identify alkylpyrazines, chemists often resort to gas chromatog. retention indexes (RIs). Although there are many compilations of retention indexes of alkylpyrazines, these databases are often incomplete and the values reported are sometimes inconsistent. Herein, the authors present retention indexes of fifty-six alkylpyrazines recorded on DB-1, ZB-5MS, DB-624, and ZB-WAXplus stationary phases, and compare them with those available in the NIST-2017 MS-RI database. Furthermore, RI values can be used, together with mass spectral interpretations, to identify certain alkylpyrazines gas chromatog. mass spectrometry.

Journal of Chromatography A published new progress about Gas chromatography-mass spectrometry. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Safety of 2,3,5-Trimethylpyrazine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Almansa, Carmen published the artcileSynthesis and SAR of a new series of COX-2-selective inhibitors: pyrazolo[1,5-a]pyrimidines, Formula: C6H9N3, the main research area is pyrazolopyrimidine preparation COX2 inhibitor; pyrimidine pyrazolo preparation COX2 inhibitor; structure activity pyrazolopyrimidine COX2 inhibitor.

The synthesis and pharmacol. activity of a series of bicyclic pyrazolo[1,5-a]pyrimidines, e.g., I (R1, R2, R3 = H, Me), as potent and selective cyclooxygenase-2 (COX-2) inhibitors are described. The new compounds were evaluated both in vitro (COX-1 and COX-2 inhibition in human whole blood) and in vivo (carrageenan-induced paw edema and air-pouch model). Modification of the pyrimidine substituents showed that 6,7-disubstitution provided the best activity and led to the identification of 3-(4-fluorophenyl)-6,7-dimethyl-2-[4-(methylsulfonyl)phenyl]pyrazolo[1,5-a]pyrimidine I (R1 = H, R2 = R3 = Me) as one of the most potent and selective COX-2 inhibitors in this series.

Journal of Medicinal Chemistry published new progress about Nonsteroidal anti-inflammatory agents. 91678-81-8 belongs to class pyrazines, name is 3,5-Dimethylpyrazin-2-amine, and the molecular formula is C6H9N3, Formula: C6H9N3.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Wei, Changqing published the artcileChanges Occurring in the Volatile Constituents of Flaxseed Oils (FSOs) Prepared with Diverse Roasting Conditions, Category: pyrazines, the main research area is flaxseed oil volatile constituent diverse roasting condition.

The roasting process is the most significant factor in forming the final flavor character of FSO. A wide variety of volatile constituents in FSO prepared from flaxseeds that were roasted at different temperatures are evaluated by head-space solid phase micro-extraction (HS-SPME) coupled with GC-MS. There are 69 volatile constituents that are tentatively identified, and the sensory variance anal. indicates that all of the FSO samples gives comparable intensity values for the “”oily”” and “”herbaceous””aroma descriptors, and the odor profiles of the FSO samples differed significantly with regards to the “”roasted”” and “”almond”” aromas (p < 0.05). The principal component anal. (PCA) of the volatiles showed the first principal component (PC-1) and the second principal component (PC-2) express 84 and 9% of the volatile component variability in the FSO, resp., which can clearly differentiate FSOs prepared from different roasting conditions. Addnl., the loadings plot further shows that the RFSO correlated more with three groups of volatile constituents according to the degree of roasting (with the total numbers and numbers of specific compounds between brackets): aldehydes (19:2, (E, E)-2,4-pentadienal, (E, E)-2,4-heptadienal), ketones (9:3,2-hexanone, (E)-3-octen-2-one, 5-methyl-2(5H)-furan-one), and heterocyclic compounds (11:4, 2,3-dimethylpyrazine, trimethylpyrazine, 2-ethyl-furan, 2-ethyl-6-methylpyrazine). Practical Applications: Monitoring of the roasting process is an unavoidable task to obtain the desired volatiles and taste to ensure RFSO quality constant at an industrial level. In general, the most adopted indicator to control the degree of roasting in industry is visual inspection, which may not be accurate for the quality evaluation because RFSO presented the same average color value although they are derived from different roasted degree. Different resources will imply in variable volatile constituents for the same type of flaxseeds. It is therefore known that FSOs produced from different roasting processing may be differentiated by their volatile constituents. The results show that the major volatile constituents can be used as chem. markers to distinguish different processed RFSO by the PCA method. The roasting process contributes the most in forming the final flavor character of flaxseed oils (FSOs). By increasing the roasting temperature, the color of FSOs changed gradually from light yellow (0-40 min) to brown (40 min) and finally to deep-brown (50 min). A wide variety of volatile compounds in FSOs are evaluated and compared with those of unroasted FSO by HS-SPME-GC-MS and sensory variance. The sensory variance anal. indicates that the odor profiles of FSO samples differed significantly with regards to the ""roasted"" and ""almond"" aromas (p < 0.05). PCA anal. can clearly differentiate FSOs prepared from different roasting conditions. European Journal of Lipid Science and Technology published new progress about Headspace solid phase microextraction. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Category: pyrazines.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Wang, Furong published the artcileEffect of free amino acids and peptide hydrolysates from sunflower seed protein on the formation of pyrazines under different heating conditions, Related Products of pyrazines, the main research area is free amino acid peptide hydrolyzate sunflower seed protein pyrazine.

Most research concerning pyrazine formation in the Maillard reaction is mainly focused on free amino acids (FAAs), but limited information is available on the effect of peptides and proteins. In this study, three Maillard model systems (i.e., glucose and native sunflower seed protein, hydrolyzed peptides or FAAs, resp.) were prepared, and their effect on the formation of volatiles were further compared at different heating conditions by using of headspace solid-phase microextraction equipped with gas chromatog./mass spectrometry (HS-SPME-GC/MS). It was found that pyrazines were the characteristic volatile compounds in tested Maillard models, and with increasing heating temperature and time, the varieties of pyrazine formation significantly increased. The optimum reaction condition for pyrazine formation was at 140°C for 90 min, which was subsequently applied to all sets of Maillard models. Further anal. showed that the short chain peptides generated by hydrolyzing sunflower seed protein (SSP), especially the mol. weight ranging from 1.2 to 3.0 kDa, significantly promoted the formation of pyrazines, which highlights the important role of peptides in the Maillard reaction models and is expected to intensify aroma promotion in sunflower seed oil.

RSC Advances published new progress about Headspace solid phase microextraction. 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Related Products of pyrazines.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Fu, Ao published the artcileClassification of Fish Sauce Origin by Means of Electronic Nose Fingerprint and Gas Chromatography-Mass Spectrometry of Volatile Compounds, Product Details of C7H10N2, the main research area is fish sauce volatile compound electronic nose fingerprint GC MS.

The aims of this paper are to introduce a method to classification of fish sauce origin by means of electronic nose fingerprint and gas chromatog.- mass spectrometry of volatile compounds and the two artificial neural networks are used to predict the origins of fish sauce. Methods: Headspace sampling-solid phase microextraction combined with gas chromatog.-mass spectrometric anal. and electronic nose were used to analysze volatile compounds in different origins of fish sauce, and these dates predicted the origins of fish sauce by artificial neural networks. Results: 94 volatile compounds were identified by Automatic mass spectral deconvolution and identification system, out of which 44 are from Guangdong, 53 from our laboratory, 51 from Vietnam, 47 and 45 from Thailand. Then electronic nose was applied to identify the origin of fish sauce, and the data were analyzed using principal component anal. and load anal. Lastly, two artificial neural networks are used to predict the origins of fish sauce, and the accuracy rates of radial basis and gradient descent both are 93.33%. Conclusion: That illustrates that we can provide a quick method to distinguish fish sauce products of different origins. These results indicated that the combinations of multiple anal. and identification methods could make up the limitations of a single method, enhance the accuracy of identification, and provide useful information for product development.

Current Analytical Chemistry published new progress about Fingerprint sensors (Electronic Nose). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Product Details of C7H10N2.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Preville, Cathy published the artcileSubstituted Azabicyclo[2.2.1]heptanes as Selective Orexin-1 Antagonists: Discovery of JNJ-54717793, Recommanded Product: 2-Chloro-5-(trifluoromethyl)pyrazine, the main research area is orexin OX1 OX2 SORA1 neuropeptides bioavailable brain OX1R antagonists.

The orexin system consists of two neuropeptides (orexin-A and orexin-B) that exert their mode of action on two receptors (orexin-1 and orexin-2). While the role of the orexin-2 receptor is established as an important modulator of sleep wake states, the role of the orexin-1 receptor is believed to play a role in addiction, panic, or anxiety. In this manuscript, we describe the optimization of a nonselective substituted azabicyclo[2.2.1]heptane dual orexin receptor antagonist (DORA) into orally bioavailable, brain penetrating, selective orexin-1 receptor (OX1R) antagonists. This resulted in the discovery of our first candidate for clin. development, JNJ-54717793.

ACS Medicinal Chemistry Letters published new progress about Bioavailability (orally bioavailable). 799557-87-2 belongs to class pyrazines, name is 2-Chloro-5-(trifluoromethyl)pyrazine, and the molecular formula is C5H2ClF3N2, Recommanded Product: 2-Chloro-5-(trifluoromethyl)pyrazine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Wang, Juan published the artcileStudies on the key odorants in Maopu buckwheat finished Baijiu and the effect of tartary buckwheat extract on its flavor, Synthetic Route of 14667-55-1, the main research area is odorant flavor Maopu buckwheat finished Baijiu tartary extract.

Maopu buckwheat finished Baijiu (MBFB), a unique Chinese Baijiu, is mainly composed of base Baijiu and tartary buckwheat extract (TBE). However, there is a lack of studies reporting its flavor. In this study, the key odorants in MBFB were characterized for the first time using a sensomics approach. Forty-nine odorants were identified using gas chromatog.-mass spectrometry/olfactory anal., coupled with aroma extraction dilution anal. They were quantified using multiple methods and their odor activity values were calculated Et hexanoate, Et butanoate, butanoic acid, hexanoic acid, di-Me trisulfide, p-cresol, β-damascenone, and 3-methylbutanal were confirmed as the key odorants in MBFB using recombination and omission experiments Furthermore, the interaction between TBE and odorants were revealed that TBE enhanced the sweet notes, while it inhibited the alc., acidic, and fruity notes, which might be because TBE promoted the volatility of most esters, but inhibited the volatilities of butanoic acid and hexanoic acid.

LWT–Food Science and Technology published new progress about Baijiu (Maopu buckwheat finished Baijiu). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Synthetic Route of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Thi Le, Dung Huynh published the artcileBioactive and Physicochemical Characteristics of Natural Food: Palmyra Palm (Borassus flabellifer Linn.) Syrup, Name: 2,3,5-Trimethylpyrazine, the main research area is bioactive physicochem characteristic natural food palmyra palm; Borassus flabellifer L.; in vitro antioxidant activity; palmyra palm syrup; physicochemical characteristics; ultrafiltration; volatile compounds.

Palmyra palm syrup, produced from Borassus flabellifer flowers sap, is rich in nutrients and minerals and has unique flavors. This study evaluated the in vitro antioxidant activity, physicochem. characteristics, and Maillard reaction products of palmyra palm syrup prepared by thermal and ultrafiltration processes. Palmyra palm syrup prepared by a thermal process had smaller L*, b* values, and larger a* values than that prepared by an ultrafiltration process. Palmyra palm syrup contained 10 vitamins, the most abundant being vitamin E. Overall, 38 volatile compounds were found and classified into six groups in the order of alcs. > acids > ketones > sulfurs > pyrazines> phenols and aldehyde. Volatile compounds depended on concentration, temperature, and ultrafiltration process. Protein content decreased because of participation in the Maillard reaction and increased 5-hydroxymethylfurfural (HMF) and total phenolic content. The HMF content was very low (0.02-14.95 mg/100 g). The radical scavenging activity of 2,2-diphenyl-1-1 picrylhydrazyl and 2,20-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) in palmyra palm syrup with thermal process was higher than with ultrafiltration. This study established that ultrafiltration pretreatment of palmyra palm syrup generated a good appearance and reduced the HMF content, however, it neg. affected the volatile compounds and physicochem. characteristics.

Biology (Basel, Switzerland) published new progress about Acids Role: ANT (Analyte), ANST (Analytical Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Name: 2,3,5-Trimethylpyrazine.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Zhou, Qi published the artcileCharacterization of the Aroma-Active Compounds in Commercial Fragrant Rapeseed Oils via Monolithic Material Sorptive Extraction, Quality Control of 14667-55-1, the main research area is aroma rapeseed oil monolithic material sorptive extraction GC MS; OAV; aroma-active compounds; commercial fragrant rapeseed oils; monolithic material sorptive extraction.

Com. fragrant rapeseed oil (CFRO), from roasted and hot-pressed seed, is enjoyed in China for its unique aroma. However, the characteristic of aroma-active compounds in CFRO is still unclear. In this study, a new odor monolithic material sorptive extraction method was established to trap volatiles from rapeseed oil. Thirty CFROs were investigated using this method coupled with gas chromatog.-mass spectrometry(GC-MS). A total of 29 volatile compounds were identified by gas chromatog.-olfactometry(GC-O) including pyrazines, alcs., aldehydes, ketones, and sulfur compounds,. Further, 2,5-dimethylpyrazine(peanut-like), 3-ethyl-2,5-dimethylpyrazine(roasted nut-like), di-Me trisulfide(cabbage-like), 4-isothiocyanato-1-butene(pungent and pickle-like), butyrolactone(caramel-like), and benzyl nitrile(pungent and sulfur-like) are affirmed as the key odorants for the overall aroma of CFRO, owing to their odor activity values≥1. This work provides a new insight on acquiring aroma-active compounds from rapeseed oil in a more time-effective process compared to conventional methods. This novel approach is applicable in the field of food flavor in the further.

Journal of Agricultural and Food Chemistry published new progress about Alcohols Role: ANT (Analyte), ANST (Analytical Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Quality Control of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Marseglia, Angela published the artcileVolatile fingerprint of unroasted and roasted cocoa beans (Theobroma cacao L.) from different geographical origins, Synthetic Route of 14667-55-1, the main research area is cocoa bean authenticity volatile geol HSSPME GC MS; Authenticity; Fermented cocoa beans; Fingerprint; Geographical origin; Roasted cocoa beans; Volatilome.

The aroma characterization of 58 unroasted cocoa beans from 22 different geog. origins was performed by head space solid phase micro-extraction (HS-SPME) combined with gas chromatog.-mass spectrometry (GC-MS). Sampling is representative of the average world production (America, Africa, and Southeast Asia). Anal. of cocoa beans before and after roasting were performed to follow the aroma modification with the aim to achieve a cocoa volatile fingerprint and a discrimination model based on beans origin. A total of 57 volatiles was identified in unroasted cocoa beans, while 71 volatiles were identified in roasted cocoa beans. The compounds belong to several chem. groups including esters, alcs., organic acids, aldehydes, ketones and pyrazines. Datasets were submitted to multivariate statistical anal. (Principal Component Anal., PCA). Results allowed to discriminate unroasted cocoa beans based on their geog. origin: samples coming from African countries were separated from samples of American regions, whereas samples from Southeast Asia lie between the other two continents suggesting that Asian samples have intermediate characteristics between African and South American cocoa beans. PCA, applied on the corresponding roasted samples, showed that although the same roasting treatment has been applied to all the samples, the differences among the unroasted samples were also maintained in the aromatic profile after roasting. The discrimination model based on volatile fingerprint combined with chemometric tools, showed interesting potential for origin authentication of both unroasted and roasted cocoa beans.

Food Research International published new progress about Alcohols Role: ANT (Analyte), ANST (Analytical Study). 14667-55-1 belongs to class pyrazines, name is 2,3,5-Trimethylpyrazine, and the molecular formula is C7H10N2, Synthetic Route of 14667-55-1.

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem