Month: January 2023

Screening and characteristic aroma analysis of aroma-producing yeasts in high-temperature Daqu was written by Lu, Yan-xiang;Liang, Hui-zhen;Chen, Peng;Liu, Zheng;Zhong, Cheng. And the article was included in Shipin Yanjiu Yu Kaifa in 2021.Safety of Isopentyl 3-methylbutanoate This article mentions the following:

Two yeast strains characterized by high aroma production, namely Y3 and Y5, were obtained from the high-temperature Daqu. After separation and purification, primary screening for aroma production using liquid fermentation, and secondary screening using solid fermentation were performed. Headspace solid-phase microextraction-gas chromatog.-mass spectrometry (HS-SPME-GC-MS) was employed to detect and analyze the products obtained after solid-state fermentation of Y3 and Y5. As a result, 43 and 37 volatile aroma compounds were recovered from Y3 and Y5, resp. The main aroma producing compounds among the products obtained after Y3 solid-state fermentation were β-phenethyl alc., isoamyl alc., isovaleric acid, and Et butyrate, and those obtained after Y5 solid-state fermentation were β-phenylethanol, 4-vinylguaiacol, and isoamyl alc. acid. Based on the morphol., physiol., and biochem. examinations, and mol. identification, Y3 was identified as Saccharomycopsis fibuligera, and Y5 was identified as Wickerhamomyces anomalus. Thereafter, Y3 and Y5 were mixed in equal proportions, and added to the Maotai-flavored liquor fermented grains to simulate the production and fermentation, and then the distilled liquor samples were examined using gas chromatog. (GC) for skeleton composition The results revealed that both Y3 and Y5 significantly increased the levels of Et acetate, Et lactate, and β-phenylethanol in liquor. In the experiment, the researchers used many compounds, for example, Isopentyl 3-methylbutanoate (cas: 659-70-1Safety of Isopentyl 3-methylbutanoate).

Isopentyl 3-methylbutanoate (cas: 659-70-1) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.Safety of Isopentyl 3-methylbutanoate

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

Using a bio-inspired surface resonance plasmon electronic nose for fundamental research on human olfaction was written by Mantel, Marylou;Fournel, Arnaud;Staedle, Ines;Oelschlagel, Annegret;Carro, Jeanne;Dubreuil, Romain;Herrier, Cyril;Livache, Thierry;Haehner, Antje;Hummel, Thomas;Roy, Jean-Michel;Bensafi, Moustafa. And the article was included in Sensors and Actuators, B: Chemical in 2022.Formula: C9H10O3 This article mentions the following:

Electronic noses are artificial devices designed to detect and classify odors, used for many industrial applications but they can also be a tool for fundamental research on the chem. senses. Indeed, one major issue in research on olfaction is that the relationship between the structure of volatile olfactory compounds and the perception they evoke is still little understood. Acknowledging the importance of biol. in the equation, the present study offers a new way to approach to stimulus-percept problem in olfaction, 1/ by considering as stimulus the interaction between odorants and olfactory receptors and 2/ by extending the measure of percept and considering the issue of interindividual diversity. To this end, we used a bio-inspired surface resonance plasmon electronic nose (e-nose) and acquired response patterns for 20 representative odorants. We also collected perceptual ratings (on intensity, pleasantness, familiarity, edibility and irritation) and verbal description of the perceptual experience associated to these odorants in a sample of 74 individuals. Combining Principal Component Anal. and Dissimilarity Matrix Anal., we showed a relationship between the e-nose space and both measures of perception, but only for odorants eliciting homogenous responses among the subjects. This study thus shows the relevance of a bio-inspired e-nose as a model of olfactory receptors interactions for the study of natural olfaction. In the experiment, the researchers used many compounds, for example, Ethyl 2-hydroxybenzoate (cas: 118-61-6Formula: C9H10O3).

Ethyl 2-hydroxybenzoate (cas: 118-61-6) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.Formula: C9H10O3

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

Improvement of enantioselectivity and stability of Klebsiella oxytoca hydrolase immobilized on Eupergit C 250L was written by Wang, Pei-Yun;Tsai, Shau-Wei;Chen, Teh-Liang. And the article was included in Journal of Chemical Technology and Biotechnology in 2008.Recommanded Product: Ethyl 2-hydroxy-3-phenylpropanoate This article mentions the following:

A simple procedure was employed to covalently immobilize a Klebsiella oxytoca hydrolase (SNSM-87) onto epoxy-activated supports of Eupergit C 250L via multipoint covalent attachment. The resultant biocatalyst was explored for the hydrolytic resolution of a variety of (R,S)-2-hydroxycarboxylic acid Et esters. Results: With the hydrolytic resolution of (R,S)-Et mandelate in biphasic media as the model system, optimal conditions of 55°, pH 6 buffer and isooctane as the organic phase were selected for improving the enzyme stability (activity retained from 10% to 50% at 96 h) and enantioselectivity (V_SV_R^-1 value enhanced from 44 to 319) in comparison to the performance of free enzyme. Moreover, the immobilized enzyme retained its activity and enantioselectivity after eight cycles of hydrolysis at 55°. When applying the resolution process to other (R,S)-2-hydroxycarboxylic acid Et esters, 2.4- to 4.0-fold enhancements of the enantioselectivity in general were obtainable. The enantioselectivity enhancement, good reusability and easy recovery after reaction indicate that the immobilized SNSM-87 may have the potential as an industrial biocatalyst for the preparation of optically pure 2-hydroxycarboxylic acids. In the experiment, the researchers used many compounds, for example, Ethyl 2-hydroxy-3-phenylpropanoate (cas: 15399-05-0Recommanded Product: Ethyl 2-hydroxy-3-phenylpropanoate).

Ethyl 2-hydroxy-3-phenylpropanoate (cas: 15399-05-0) belongs to esters. Esters perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester as the reaction product. Esters are common in organic chemistry and biological materials.Recommanded Product: Ethyl 2-hydroxy-3-phenylpropanoate

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

Measurement of the Effect of Accelerated Aging on the Aromatic Compounds of Gewurztraminer and Teroldego Wines, Using a SPE-GC-MS/MS Protocol was written by Carlin, Silvia;Lotti, Cesare;Correggi, Ludovica;Mattivi, Fulvio;Arapitsas, Panagiotis;Vrhovsek, Urska. And the article was included in Metabolites in 2022.Product Details of 706-14-9 This article mentions the following:

Knowing in detail how the white and red wine aroma compounds behave under various storage conditions and especially at high temperature is important in order to understand the changes occurring to their sensorial character during the shelf life. The initial aim of this work was to develop and validate a fast, modern, robust, and comprehensive protocol for the quantification of 64 primary, secondary, and tertiary volatile compounds by using solid-phase extraction (SPE) cartridges in sample preparation and fast GC-MS/MS (gas chromatog.-tandem mass spectrometry assay) in anal. The protocol was applied to a study of the behavior of seven Gewurztraminer and seven Teroldego wines stored in anoxia at 50°C for 2.5 and 5 wk. The results demonstrated a sharp decrease of the main linear terpenes linalool, geraniol, and nerol and the consequent increase of the cyclic ones, such as α-terpineol and 1,8-cineole; the increase of the C13-norisoprenoids 1,1,6,-trimethyl-1,2-dihydronaphthalene (TDN), and β-damascenone and the C10 norisoprenoid safranal; the hydrolysis of acetates and linear esters; and the increase of some branched-chain esters. In red wines, a moderate increase was observed for some lactones. Some unwanted compounds, such as 2-aminoacetophenone (2-AAP), showed a notable increase in some Gewurztraminer wines, exceeding the olfactory threshold. In the experiment, the researchers used many compounds, for example, 5-Hexyldihydrofuran-2(3H)-one (cas: 706-14-9Product Details of 706-14-9).

5-Hexyldihydrofuran-2(3H)-one (cas: 706-14-9) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.Product Details of 706-14-9

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

Organocatalyzed Asymmetric Tandem Intramolecular oxa-Michael Addition/Electrophilic Thiocyanation: Synthesis of Chiral α-Thiocyanato Flavanones was written by Gao, Yong;Fu, Zhenda;Wu, Di;Yin, Hongquan;Chen, Fu-Xue. And the article was included in Asian Journal of Organic Chemistry in 2022.Synthetic Route of C9H10O3 This article mentions the following:

An efficient bifunctional cinchona alkaloids-catalyzed asym. tandem intramol. oxa-Michael addition/electrophilic thiocyanation of alkylidene β-ketoesters with N-thiocyanatosuccinimide (NTS) was developed. A series of chiral α-thiocyanato flavanones containing two vicinal stereocenters including an all-carbon quaternary center I [R¹ = H, 7-Me, 6-Cl; R² = Ph, 2-naphthyl, 2-thienyl, etc.; R³ = Me, Et, t-Bu] were prepared in good yields with excellent diastereo- and enantioselectivities (up to 97% ee) under mild conditions, and a successful scale up preparation of our protocol was also demonstrated. In the experiment, the researchers used many compounds, for example, Ethyl 2-hydroxybenzoate (cas: 118-61-6Synthetic Route of C9H10O3).

Ethyl 2-hydroxybenzoate (cas: 118-61-6) belongs to esters. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.Synthetic Route of C9H10O3

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

Catalytic dynamic kinetic resolutions with N-heterocyclic carbenes: Asymmetric synthesis of highly substituted β-lactones was written by Cohen, Daniel T.;Eichman, Chad C.;Phillips, Eric M.;Zarefsky, Emily R.;Scheidt, Karl A.. And the article was included in Angewandte Chemie, International Edition in 2012.Safety of Ethyl 3-oxo-3-(m-tolyl)propanoate This article mentions the following:

A new NHC-catalyzed (N-heterocyclic carbenes) DKR (dynamic kinetic resolution) with β-keto esters to generate highly substituted β-lactones with excellent levels of stereoselectivity has been developed. This process takes advantage of the conditions necessary to generate the active NHC catalyst to simultaneously promote the epimerization of a β-ketoester substrate. The present study provides efficient access to highly enantioenriched β-lactones and cyclopentenes in good yield with good to excellent diastereoselectivity. In the experiment, the researchers used many compounds, for example, Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9Safety of Ethyl 3-oxo-3-(m-tolyl)propanoate).

Ethyl 3-oxo-3-(m-tolyl)propanoate (cas: 33166-79-9) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits. Because of their lack of hydrogen-bond-donating ability, esters do not self-associate. Consequently, esters are more volatile than carboxylic acids of similar molecular weight.Safety of Ethyl 3-oxo-3-(m-tolyl)propanoate

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

Comparative evaluation of the volatile profiles and taste properties of roasted coffee beans as affected by drying method and detected by electronic nose, electronic tongue, and HS-SPME-GC-MS was written by Dong, Wenjiang;Hu, Rongsuo;Long, Yuzhou;Li, Hehe;Zhang, Yanjun;Zhu, Kexue;Chu, Zhong. And the article was included in Food Chemistry in 2019.Reference of 118-61-6 This article mentions the following:

In this study, room-temperature drying, solar drying, heat pump drying (HPD), hot-air drying, and freeze drying were applied to investigate the volatile profiles and taste properties of roasted coffee beans by using electronic nose, electronic tongue, and headspace solid-phase microextraction gas chromatog.-mass spectrometry (HS-SPME-GC-MS). Results indicated that the drying process markedly affected pH, total titratable acidity, total solids, and total soluble solids. Significant differences existed among all samples based on drying method; and the HPD method was superior for preserving ketones, phenols, and esters. Principal component anal. (PCA) combined with E-nose and E-tongue radar charts as well as the fingerprint of HS-SPME-GC-MS could clearly discriminate samples from different drying methods, with results obtained from hierarchical cluster anal. (the Euclidean distance is 0.75) being in agreement with those of PCA. These findings may provide a theor. basis for the dehydration of coffee beans and other similar thermo-sensitive agricultural products. In the experiment, the researchers used many compounds, for example, Ethyl 2-hydroxybenzoate (cas: 118-61-6Reference of 118-61-6).

Ethyl 2-hydroxybenzoate (cas: 118-61-6) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Acyl chlorides and acid anhydrides alcoholysis is another way to produce esters. Acyl chlorides and acid anhydrides react with alcohols to produce esters. Anydrous conditions are recommended since both acyl chlorides and acid anhydrides react with water.Reference of 118-61-6

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

Phenol Ethers with a Pseudo Allylic Chain, -(Me)C:CH₂ (III); Cresotinic Series; Synthesis of Thymol was written by Behal, A.;Tiffeneau, M.. And the article was included in Bulletin de la Societe Chimique de France in 1908.Synthetic Route of C10H12O3 This article mentions the following:

Me ether of pseudo-allylorthocresol (methyl-1-methoxy-2-pseudo-allylbenzene-3) MeC₆H₃(OMe)CMe:CH₂. o-Cresotinic acid, tech., m. 163°, is esterified (1) (2) (3) with MeOH and H₂SO₄. Me ester m. 28°-30°, b. 235°. CH₃MgI gives pseudoallyl-3-orthocresol, b. 220-225°, d₂₀ = 1.040, n_D²⁰ = 1.543. This has the odor of thyme. Me sulfate gives pseudo-allyl-3-methyl-1-anisol-2, b. 217-18°, d₀ = 0.9901, d₁₅ = 0.9830, n_D¹⁵ = 1.595. Reduction with Na and absolute alc. gives Me ether of isothymol, CH₃C₆H₃.OCH₃.CH(CH₃)₂, b. 210-3°, d₀ = 0.9559, d₁₉ = 0.9430, n_D¹⁹ = 1.50725. An isothymol is obtained by demethylating with HI. Me ether of pseudoallylmetacresol (methyl-1-methoxy-3-pseudo-allylbenzene-4), MeC₆H₃(OMe)CMe:CH₂. (1) (3) (4) Metacresotinic acid, m. 175-6°, is converted into its Me ester, b₁₂ 118-22°, d₀ = 1.1629, d₂₁ = 1.147, m. 27-8°. Methyl-methoxy-m-cresotinate, b. 259-61°, d₀ = 1.1462, gives on saponification, methoxy-m-cresotinic acid, m. 103°. CH₃MgI gives the alc., MeC₆H₃(OMe)CMe₂OH, b₁₁ 129-30°, d₀ = 1.0448, b. 240-6°. Dehydrated it gives methyl-1-methoxy-3-pseudo-allylbenzene-4, b. 216-9°, d₀ = 0.9835. Methylthymol, MeC₆H₃(OMe).C₃H₇, is obtained by reducing with Na and absolute alc. (1) (3) (4) the pseudo-allyl-4-methyl-1-methoxy-4-benzene and oxidizing the product with KMnO₄. Demethylation with HI yields thymol. In the experiment, the researchers used many compounds, for example, Methyl 2-methoxy-4-methylbenzoate (cas: 81245-24-1Synthetic Route of C10H12O3).

Methyl 2-methoxy-4-methylbenzoate (cas: 81245-24-1) belongs to esters. Esters perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.Synthetic Route of C10H12O3

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

Catalytic C-C coupling of diazo compounds with arylboronic acids: using surface modified sewage sludge as catalyst was written by Zhang, Zhipeng;Yu, Yang;Xie, Yuxing;Hughes, Timothy;Xu, Jun;Huang, Fei;Huang, He. And the article was included in Green Chemistry in 2020.Recommanded Product: 587-88-2 This article mentions the following:

A green, mild and efficient synthesis of diarylmethines I [R = Ac, Ph, 4-FC₆H₄, etc.; R¹ = H, Ph, 3-pyridyl, etc.; R² = Me, Et, Bn, etc.] using sewage sludge-derived carbonaceous materials (SW) by perchloric acid catalyzed coupling reactions between diazo compounds and arylboronic acids was developed. The reaction showed a high level of functional tolerance and a broad substrate scope. Furthermore, the highly selective 1,2-alkyl shift product chromenones II [R³ = H, 6-F, 6-Br; R⁴ = Me; R⁵ =Me, Et; R⁴R⁵ = (CH₂)₄, (CH₂)₂O(CH₂)₂, CH₂C(Me)₂(CH₂)₃] were furnished through the sterically demanding groups migration of diazo compounds (3-diazochromanone). The structures of 1,2-shift products were further confirmed by single-crystal X-ray anal. Significantly, the synthesis of the core structures of darifenacin (a clin. drug for overactive bladder syndrome, OAB) and diclofensine (a stimulant drug showing antidepressant and monoamine reuptake inhibitor activity) further demonstrated the efficacy and synthetic potential of this method. In the experiment, the researchers used many compounds, for example, Ethyl 2-(4-fluorophenyl)acetate (cas: 587-88-2Recommanded Product: 587-88-2).

Ethyl 2-(4-fluorophenyl)acetate (cas: 587-88-2) belongs to esters. Carboxylic acid esters of low molecular weight are colourless, volatile liquids with pleasant odours, slightly soluble in water. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.Recommanded Product: 587-88-2

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

Intrapopulation and temporal differences of phthalate concentrations in North Atlantic fin whales (Balaenoptera physalus) was written by Garcia-Garin, Odei;Sahyoun, Wissam;Net, Sopheak;Vighi, Morgana;Aguilar, Alex;Ouddane, Baghdad;Vikingsson, Gisli A.;Chosson, Valerie;Borrell, Asuncion. And the article was included in Chemosphere in 2022.Reference of 84-61-7 This article mentions the following:

The fin whale (Balaenoptera physalus) is a migratory filter-feeding species that is susceptible to ingest plastics while lunge feeding across the oceans. Plastic additives, such as phthalates, are compounds that are added to plastics to give them specific characteristics, such as flexibility. These so-called plasticizers are currently raising major concern because of their potential adverse effects on marine fauna. However, little is known about phthalate concentrations in tissues of baleen whales as well as their potential relation with biol. variables (i.e., sex, body length and age) and their trends with time. In this study, we assessed the concentration of 13 phthalates in the muscle of 31 fin whales sampled in the feeding grounds off western Iceland between 1986 and 2015. We detected 5 of the 13 phthalates investigated, with di-n-butylphthalate (DBP), diethylphthalate (DEP) and bis(2-ethylhexyl) phthalate (DEHP) being the most abundant. None of the biol. variables examined showed a statistically significant relationship with phthalate concentrations Also, phthalate concentrations did not significantly vary over the 29-yr period studied, a surprising result given the global scenario of increasing plastic pollution in the seas. The lack of time trends in phthalate concentration may be due in part to the fact that phthalates also originate from other sources. Although no adverse effects of phthalates on fin whales have been detected to date, further monitoring of these pollutants is required to identify potential toxic effects in the future. In the experiment, the researchers used many compounds, for example, Dicyclohexyl phthalate (cas: 84-61-7Reference of 84-61-7).

Dicyclohexyl phthalate (cas: 84-61-7) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Esters contain a carbonyl center, which gives rise to 120° C–C–O and O–C–O angles. Unlike amides, esters are structurally flexible functional groups because rotation about the C–O–C bonds has a low barrier. Their flexibility and low polarity is manifested in their physical properties; they tend to be less rigid (lower melting point) and more volatile (lower boiling point) than the corresponding amides. Reference of 84-61-7

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