Day: November 21, 2022

Tran, Hai N. published the artcileNickel-Catalyzed Asymmetric Hydroarylation of Vinylarenes: Direct Enantioselective Synthesis of Chiral 1,1-Diarylethanes, Application of (4S,4’S)-2,2′-(Cyclohexane-1,1-diyl)bis(4-phenyl-4,5-dihydrooxazole), the publication is Journal of Organic Chemistry (2021), 86(5), 3836-3849, database is CAplus and MEDLINE.

The enantioselective hydroarylation of vinylarenes RCH=CH₂ (R = C₆H₅, 4-FC₆H₄, 2-naphthyl, etc.) catalyzed by a chiral, non-racemic nickel catalyst is presented as a facile method to generate chiral 1,1-diarylethanes (R)/(S)-RCH(CH₃)R¹ (R¹ = C₆H₅, 4-CH₃OC₆H₄, 2-naphthyl, etc.). These reactions proceed via formation of a chiral, non-racemic nickel benzyl intermediate. Transmetalation with arylboron nucleophiles and subsequent reductive elimination enable the formation of a variety of chiral 1,1-diarylethanes. The 1,1-diarylethane products from reactions of arylboronic acids R¹B(OH)₂ containing electron-donating substituents are formed with typically greater than 90% ee, while the 1,1-diarylethanes generated from reactions of arylboronic acids containing electron-withdrawing groups are generated with typically less than 80% ee. These results are consistent with the rate of transmetalation with an arylboron nucleophile playing a key role in the enantioselectivity of these hydroarylation reactions. This mechanistic insight has led to the development of reactions of neo-pentylglycolate esters like 4-methoxyphenylboronic acid neopentylglycol ester, 4-uorophenylboronic acid neopentylglycol ester and 4-(trifluoromethyl)phenylboronic acid neopentylglycol ester of arylboronic acids with vinylarenes that occur with higher enantioselectivities based on increased rates of transmetalation.

Journal of Organic Chemistry published new progress about 2185014-88-2. 2185014-88-2 belongs to oxazolidine, auxiliary class BOX Ligands, name is (4S,4’S)-2,2′-(Cyclohexane-1,1-diyl)bis(4-phenyl-4,5-dihydrooxazole), and the molecular formula is C8H11BO2, Application of (4S,4’S)-2,2′-(Cyclohexane-1,1-diyl)bis(4-phenyl-4,5-dihydrooxazole).

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Schwanz, Thiago G. published the artcileAnalysis of chemosensory markers in cigarette smoke from different tobacco varieties by GC×GC-TOFMS and chemometrics, Quality Control of 20662-83-3, the publication is Talanta (2019), 74-89, database is CAplus and MEDLINE.

Com. cigarettes are made from a blend of different tobacco varieties, which in turn are the results of different agronomic practices and post-harvest curing processes. The highly complex mixture of smoke compounds reflects each tobacco variety and the levels of sensory-relevant markers. Therefore, the aim of this work was to identify potential relevant chemosensory markers in the mainstream smoke of four main types of com. tobaccos and establish any possible relationship between them and the tobacco growing/curing practices. The tobacco samples were segregated into four segments: (1) three curing stages of flue-cured Virginia, (2) three curing stages of air-cured Burley, (3) three geo-regions of sun-cured Oriental and (4) three different process applied to tobacco. One hundred and twenty cigarettes (10 batches per flavor category) were produced and smoked under standard machine-smoking protocols. The mainstream smoke samples collected were extracted and analyzed by GC × GC TOFMS. The processed data was analyzed by partial least square discriminant anal. (PLS-DA) and the selectivity ratio was used to identify key chemosensory markers responsible for the four segments. All models had sensitivity and specificity equal to unity. Flue-cured Virginia (193 markers) and air-cured Burley (184 markers) showed a similar trend for O-heterocycles markers in the lighter leaf colors and N-heterocycles in the darker leaf colors post-processing, but they had compounds of different flavor descriptions, e. g. sweet and nutty. The three geo-regions of sun-cured Oriental (290 markers) also presented O-heterocycles markers in correlation with leaf sugar contents in addition of sucrose esters markers. The three unusually processed tobacco generated many chem. markers (436 markers), some derived from the so-called Cavendish fermentation process with sweet, spicy and peppery notes, whereas the dark fermented air-cured tobacco presented similar descriptors as air-cured Burley. In addition, some polycyclic aromatic hydrocarbons (PAH) were detected as markers from the fire-curing process. The PLS-DA with selectivity ratio evidenced total of 1098 chemosensory markers in cigarette smoke, in which 173 were tentatively identified.

Talanta published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C11H10N4, Quality Control of 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Baltes, Werner published the artcileModel reactions on roast aroma formation. V. Mass spectrometric identification of pyridines, oxazoles, and carbocyclic compounds from the reaction of serine and threonine with sucrose under the conditions of coffee roasting, Application of 4,5-Dimethyloxazole, the publication is Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung (1987), 185(1), 5-9, database is CAplus.

From the reaction of serine, threonine and sucrose under the conditions of coffee roasting, 33 pyridines, 20 oxazoles, and 12 carbocyclic compounds, among others, were identified in the volatile fraction. Their mass spectra and retention indexes are reported and the reaction products were compared with those formed by roasting coffee under the same conditions.

Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Application of 4,5-Dimethyloxazole.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Qian, Deyun published the artcileChiral Alkyl Amine Synthesis via Catalytic Enantioselective Hydroalkylation of Enecarbamates, SDS of cas: 138429-17-1, the publication is Journal of the American Chemical Society (2021), 143(4), 1959-1967, database is CAplus and MEDLINE.

A nickel-catalyzed hydroalkylation method to assemble a wide range of chiral alkyl amines from enecarbamates (N-Cbz-protected enamines) and alkyl halides with high regio- and enantioselectivity was reported. The method works for both nonactivated and activated alkyl halides and was able to produce enantiomerically enriched amines with two minimally differentiated α-alkyl substituents. The mild conditions led to high functional group tolerance, which is demonstrated in the postproduct functionalization of many natural products and drug mols., as well as the synthesis of chiral building blocks and key intermediates to bioactive compounds

Journal of the American Chemical Society published new progress about 138429-17-1. 138429-17-1 belongs to oxazolidine, auxiliary class BOX Ligands, name is (4S,4’S)-4,4′-Diisobutyl-4,4′,5,5′-tetrahydro-2,2′-bioxazole, and the molecular formula is C14H24N2O2, SDS of cas: 138429-17-1.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Solina, Marica published the artcileVolatile aroma components of soy protein isolate and acid-hydrolyzed vegetable protein, SDS of cas: 20662-83-3, the publication is Food Chemistry (2004), 90(4), 861-873, database is CAplus.

The volatile aroma components of soy protein isolate (SPI) and acid-hydrolyzed vegetable protein (aHVP) were compared by GC-MS and GC-olfactometry (GCO). Major differences were found between the 2 soy-based products. Aliphatic aldehydes and ketones were mainly found in SPI, whereas pyrazines and sulfur-containing compounds were dominant in aHVP. Analyses of the non-volatile components showed that SPI was mainly protein (82.5%) with some lipid (3.5%), whereas aHVP contained no protein, only free amino acids (18.4%) and a trace quantity of lipid (0.4%). Polyunsaturates (47.8%), followed by saturates (24.9%) and monounsaturates (14.8%) dominated the fatty acid profile of the SPI lipid fraction. Both SPI and aHVP had a free fatty acid content <0.1%. Sensory analyses of aqueous suspensions of SPI and aHVP demonstrated significant differences in the odors of the 2 products. Compounds responsible for some of these differences were identified by GCO and GC-MS analyses of aqueous suspensions. The possible role of SPI and aHVP in the development of aroma in extrudates containing these soy products is discussed.

Food Chemistry published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C4H6N2, SDS of cas: 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Viegas, Marcelo Caldeira published the artcileUse of the linear retention index for characterization of volatile compounds in soluble coffee using GC-MS and an HP-innowax column, Safety of 4,5-Dimethyloxazole, the publication is Quimica Nova (2007), 30(8), 2031-2034, database is CAplus.

Due to the complexity of the soluble coffee matrix, complete identification of flavor components should not be based on GC-MS anal. only. The linear retention index (LRI) is frequently used to give support to mass spectral data. Volatile compounds in dry lyophilized soluble Arabic coffee samples were characterized by head-space (solid-phase microextraction) GC-MS; the LRI values were determined with the HP-Innowax column. The combined method significantly increased the reliability of identifying the volatile compounds; 88 volatile compounds were identified.

Quimica Nova published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C2H2N4O2, Safety of 4,5-Dimethyloxazole.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Piloty, Markus published the artcileInvestigations on the reaction of amino acids with α-dicarbonyl compounds. II. Volatile products of the reaction of amino acids with diacetyl (2,3-butanedione), COA of Formula: C5H7NO, the publication is Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung (1979), 168(5), 374-80, database is CAplus.

Glycine [56-40-6], α-alanine [56-41-7], β-alanine [107-95-9], phenylalanine [63-91-2], glycylalanine [3695-73-6], and NH₃ were reacted with diacetyl [431-03-8], in an aqueous medium. In addition to several N-free compounds, some nitrogenous heterocyclic products belonging to the classes oxazoles, pyrazines, pyrroles, and pyridines were identified. The pyridine derivatives have not previously been described in the literature. Spectral data are given and possible mechanisms of formation discussed in relation to food aroma.

Zeitschrift fuer Lebensmittel-Untersuchung und -Forschung published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, COA of Formula: C5H7NO.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Ribeiro, J. S. published the artcilePrediction of sensory properties of Brazilian Arabica roasted coffees by headspace solid phase microextraction-gas chromatography and partial least squares, SDS of cas: 20662-83-3, the publication is Analytica Chimica Acta (2009), 634(2), 172-179, database is CAplus and MEDLINE.

Volatile compounds in fifty-eight Arabica roasted coffee samples from Brazil were analyzed by SPME-GC-FID and SPME-GC-MS, and the results were compared with those from sensory evaluation. The main purpose was to investigate the relationships between the volatile compounds from roasted coffees and certain sensory attributes, including body, flavor, cleanliness and overall quality. Calibration models for each sensory attribute based on chromatog. profiles were developed by using partial least squares (PLS) regression. Discrimination of samples with different overall qualities was done by using partial least squares-discriminant anal. (PLS-DA). The alignment of chromatograms was performed by the correlation optimized warping (COW) algorithm. Selection of peaks for each regression model was performed by applying the ordered predictors selection (OPS) algorithm in order to take into account only significant compounds The results provided by the calibration models are promising and demonstrate the feasibility of using this methodol. in online or routine applications to predict the sensory quality of unknown Brazilian Arabica coffee samples. According to the PLS-DA on chromatog. profiles of different quality samples, compounds 3-methypropanal, 2-methylfuran, furfural, furfuryl formate, 5-methyl-2-furancarboxyaldehyde, 4-ethylguaiacol, 3-methylthiophene, 2-furanmethanol acetate, 2-ethyl-3,6-dimethylpyrazine, 1-(2-furanyl)-2-butanone and three others not identified compounds can be considered as possible markers for the coffee beverage overall quality.

Analytica Chimica Acta published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, SDS of cas: 20662-83-3.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Lehmann, Johannes published the artcileThe Kondrat’eva Reaction in Flow: Direct Access to Annulated Pyridines, Recommanded Product: 5-(4-Bromophenyl)oxazole, the publication is Organic Letters (2013), 15(14), 3550-3553, database is CAplus and MEDLINE.

A continuous flow inverse-electron-demand Kondrat’eva reaction has been developed that provides direct access to cycloalka[c]pyridines from unactivated oxazoles and cycloalkenes. The cycloadditions of both unactivated alkenes and deactivated oxazoles are promoted in continuous flow at elevated temperatures and pressures (230 °C, 750psi). E.g., reaction of 5-phenyloxazole and cyclopentene in presence of TFA gave 55% 4-phenyl-6,7-dihydro-5H-cyclopenta[c]pyridine (I). Annulated pyridines obtained by this one-step process are valuable scaffolds for medicinal chem.

Organic Letters published new progress about 72571-06-3. 72571-06-3 belongs to oxazolidine, auxiliary class Oxazole,Bromide,Benzene, name is 5-(4-Bromophenyl)oxazole, and the molecular formula is C9H6BrNO, Recommanded Product: 5-(4-Bromophenyl)oxazole.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem

Al-Duri, B. published the artcileSupercritical water oxidation (SCWO) for the removal of N-containing heterocyclic hydrocarbon wastes. Part I: Process enhancement by addition of isopropyl alcohol, Category: oxazolidine, the publication is Journal of Supercritical Fluids (2016), 155-163, database is CAplus.

The present work investigates the destruction of nitrogen-containing heterocyclic hydrocarbons frequently encountered in hazardous wastes by supercritical water oxidation (SCWO), with focus on the process enhancement using iso-Pr alc. (IPA) as co-fuel. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was selected for SCWO in a continuous plug flow reactor, under a range of temperatures (400-525°C), oxidant ratios nSR (0.8-2.0) and IPA/DBU ratios (0.5-3.5). Exptl. results were presented in terms of total organic carbon (TOC) removal %, and nitrogenous products yield %. Based on GC-MS anal., a free radical reaction mechanism for SCWO of DBU was proposed. Results showed that temperature was the predominant factor to influence the rate of DBU oxidation, while oxidant ratio (nSR) significantly affected the N speciation in the exit stream. IPA addition had a significant impact on shifting recalcitrant aqueous ammonia NH⁺₄ in the liquid stream to gaseous nitrogen. It also increased TOC removal% (DBU + IPA) due to the increased free radicals produced by IPA oxidation

Journal of Supercritical Fluids published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, Category: oxazolidine.

Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem