JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2025
·
IF 4.6
Wei Dai,Wenjun Tan,Xuepeng Chen,Jilei Wang,Yougui Yu,Qing Zheng
This study investigates the interconversion between acetaldehyde and its acetal derivatives during the aging process of Baijiu. Acetaldehyde imparts a pungent aroma, while acetal contributes soft fruity and sweet notes to Baijiu. The dynamic equilibrium between these two compounds, mediated by a reversible reaction, significantly influences the aromatic balance and overall flavor harmony of the liquor. By analyzing aging data from Baijiu samples of different alcohol contents (62°, 52°, and 38° ABV) and aromatic types ( Nong , Jiang , Feng , Jian ), we calculated the apparent equilibrium constant (K) and developed a model predicting the simplified equilibrium constant as a function of alcohol content. Results revealed that reduced alcohol content shifts the equilibrium toward acetaldehyde formation, diminishing acetal-derived aromas. This study pioneers a thermodynamic quantitative model for acetaldehyde-acetal interconversion in Baijiu, elucidates the regulatory role of alcohol content in reaction equilibrium through solvent effects. These findings contribute significantly to the scientific understanding of Baijiu aging and offer practical solutions for flavor optimization in Baijiu production, particularly for low-alcohol Baijiu.
研究领域:
食品化学
·
风味科学
·
物理化学
·
热力学
·
酿造技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2018
·
IF 4.513
Kemeng Shi,Christian Marcus Pedersen,Zhaohui Guo,Yanqiu Li,Hongyan Zheng,Yan Qiao,Tuoping Hu,Yingxiong Wang
The tautomer distributions of d ‑fructose, a popular model compound for biorefinery , in various lower alcohols and DMSO‑ d 6 (ROHs/DMSO‑ d 6 ) mixtures at 298 K were investigated by quantitative 13 C NMR. The tautomer distributions of d ‑fructose in ethanol/DMSO‑ d 6 and methanol/DMSO‑ d 6 with different volume ratios of alcohols to DMSO‑ d 6 were also examined. For these normal alcohols (methanol, ethanol, n ‑propanol and n ‑butanol)/DMSO‑ d 6 , the tautomer distribution of d ‑fructose in methanol/DMSO‑ d 6 exhibited the shortest equilibration time (46 h) and the lowest concentration of β‑furanose (39.0%) at equilibrium. The fraction of fructofuranose (α‑furanose and β‑furanose) at equilibrium and time needed to reach equilibrium in branched chain alcohols/DMSO‑ d 6 obey the following order: 2‑propanol/DMSO‑ d 6 (62.2%, 320 h) > tert ‑butanol/DMSO‑ d 6 (61.6%, 307 h) > 2‑butanol/DMSO‑ d 6 (60.6%, 216 h) > isobutanol/DMSO‑ d 6 (57.8%, 134 h). For the diols/DMSO‑ d 6 , the time for the tautomer distribution of d ‑fructose to reach the equilibrium was found to be: 1,4‑butanediol/DMSO‑ d 6 (113 h) > 1,2‑propanediol/DMSO‑ d 6 (38 h) > ethylene glycol/DMSO‑ d 6 (36 h). For ethanol/DMSO‑ d 6 and methanol/DMSO‑ d 6 with respectively different volume ratios, the experimental results showed that the high concentration of ethanol or methanol increases the conversion rate of tautomers.
研究领域:
生物化学
·
分析化学
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产品关联
DOI
高影响因子
MAGNETIC RESONANCE IN CHEMISTRY
·
2020
·Vol. 59
·期 6
·641-647
·
IF 2.035
Xuming Sha,Shaodong Chen,Xiaojing Zheng,Xin Ye,Hailu Zhang,Shaohua Huang
In this work, tautomeric preference of fenobam in solution was investigated by homonuclear and heteronuclear solution nuclear magnetic resonance (NMR) spectroscopy. 1 H– 1 H nuclear Overhauser effect spectroscopy (NOESY) spectrum revealed that fenobam in liquid state exists exclusively in one of the two possible tautomeric structures, which was confirmed by 1 H– 13 C HSQC and heteronuclear multiple bond correlation (HMBC) spectra. Moreover, difference between the two tautomeric structures was studied by theoretical calculations, which further proved the result obtained by the NMR experiments.
研究领域:
药理学
·
分析化学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2019
·Vol. 21
·期 3
·649-657
·
IF 9.405
Xing Li,Yue Qi,Guozong Yue,Qianxun Wu,Yang Li,Meicheng Zhang,Xinghua Guo,Xiaofeng Li,Lijian Ma,Shoujian Li
A green and facile solvent- and catalyst-free method, without inert gas protection and/or mechanical grinding to synthesize an azine-linked covalent organic framework (ACOF) with high efficiency, was proposed for the first time. Characterization techniques and experimentations show that the as-synthesized ACOF has high crystallinity and superior physical and chemical stability and exhibits good adsorption performance for both radioactive heavy metal U(VI) and ordinary heavy metal Hg(II), with adsorption capacities of 169 mg g−1 for U(VI) and 175 mg g−1 for Hg(II), which makes the ACOF a potential adsorbent material for heavy metal removal and uranium recycling. Tautomerization between the enol-form and keto-form was verified in the structure of the ACOF which can be induced by the adsorption of metal ions and also affect the adsorption properties simultaneously. It was found that tautomerization from the enol-form to keto-form was promoted in the adsorption, which can be ascribed to the better coordination ability of CO in the keto-form towards the target metal ion, while the selectivity of the ACOF towards U(VI) increases with the decreasing solution pH and reaches 96.2% when the pH is 1.5, which is due to the tautomerization from the keto-form to enol-form under acidic conditions and the consequent size-matching effect. The study on tautomerization in solid materials is rarely reported and is of great importance for deep understanding of the relationship between material structures and properties. The synthesis strategy proposed in this paper provides references for the convenient, efficient and green synthesis of COFs.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 34
·15336-15343
·
IF 3.591
Yun-Feng Tao,Yu-Juan He,Jin-Zhi Ye,Xiao Yang,Ying-Ying Yang,Ge-Ge Xie,Lan-Xiang Liu,Guan-Ben Du,Hong Zhang,Bei Zhou
Natural product-originated carbon dots represent a charming and valuable platform for bio-fluorescence probes; however, the application scope of these probes is seriously restricted, due to the indistinct molecular structures of these bio-probes and the inaccurate interactions between the probe and detected guest molecule. Herein, a novel strategy of keto–enol tautomerism-mediated quinone aromatization has been achieved for Cochineal bio-based quinone carbon dot synthesis. Then, a photo-induced intermolecular cross-redox reaction was accomplished with tetracycline for quinone carbon dot molecule transformation and fluorescence change. This work represents a pioneer for intermolecular interaction simulation and bonding energy evaluation of carbon dots for trace organics detection.
研究领域:
材料科学
·
生物化学
·
分析化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Ruibo Zhong,Mingshu Xiao,Changfeng Zhu,Xizhong Shen,Qian Tang,Weijia Zhang,Lihua Wang,Shiping Song,Xiangmeng Qu,Hao Pei,Cheng Wang,Li Li
By incorporating hemin into G-quadruplex (G4) during cation-templated self-assembly between guanosine and KB(OH)4, we have constructed an artificial enzyme hydrogel (AEH)-based system for the highly sensitive and selective detection of Pb2+. The sensing strategy is based on a Pb2+-induced decrease in AEH activity. Because of the higher efficiency of Pb2+ for stabilizing G4 compared with K+, the Pb2+ ions substitute K+ and trigger hemin release from G4, thus giving rise to a conformational interconversion accompanied by the loss of enzyme activity. The Pb2+-induced catalytic interconversion endows the AEH-based system with high sensitivity and selectivity for detecting Pb2+. As a result, the AEH-based system shows an excellent response for Pb2+ in the range from 1 pM to 50 nM with a limit of detection of ∼0.32 pM, which is much lower than that of the previously reported G4-DNAzyme. We also demonstrate that this AEH-based system exhibits high selectivity toward Pb2+ over other metal ions. Furthermore, two two-input INHIBIT logic gates have been constructed via switching of the catalytic interconversion induced by K+ and Pb2+ or K+ and pH. Given its versatility, this AEH-based system provides a novel platform for sensing and biomolecular computation.
研究领域:
生物化学
·
分析化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Lei Jin,Zhi-Hao Liang,Jia-Qiang Yang,An-Ni Zheng,Zhao-Yun Wang,Fang-Zu Yang,De-Yin Wu,Zhong-Qun Tian,Dongping Zhan
5,5-Dimethylhydantoin (DMH), as a heterocyclic compound with N and O atoms, is an excellent complexing agent for trivalent gold ions . In this work, the tautomeric structures of DMH at different pH values in the solution are determined via theoretical calculations and Raman spectra . Only the ketonic form of DMH exists in weakly acidic and neutral mediums, and only the enolic form of DMH exists in highly alkaline mediums. In the weakly alkaline medium of pH 9, a large number of ketonic forms and a small number of enolic forms coexist. The coordination behavior between DMH and Au(Ⅲ) is clarified in the weakly alkaline medium of pH 9. The DMH in ketonic form is fully coordinated with Au(Ⅲ) at pH 9 and the optimal coordination structure is N2-Au with an N-Au bond energy of 16.17 eV. The electrochemical study reveals that Au(DMH) 4 − coordination ions are in the two-step electro-reductions with the first Au(Ⅲ) to Au(Ⅰ) and the second Au(Ⅰ) to Au on the gold electrode surface. The EC-SERS experiments further verify the interfacial process of tautomeric structures and Au(DMH) 4 − coordination ions.
研究领域:
化学
·
材料科学
·
电化学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Jiancheng Zhao,Rui Liu,Zhenzhou Zhang,Qianqian Xing,Honghong Chang,Xianglin Hou,Yingxiong Wang
The tautomer structure of monosaccharides plays an important role in its conversion and utilization, which is mainly manifested in the selectivity of the product and the reaction mechanism. The tautomer distributions of N -acetyl- D -glucosamine (GlcNAc), a natural nitrogen-containing monosaccharide were investigated by quantitative 1 H NMR ( 1 H qNMR) and 13 C NMR ( 13 C qNMR) at 298 K under the condition commonly utilized for biorefinery. Catalysts used for biorefinery, i.e. BaCl 2 , KCl, ZnCl 2 , MgCl 2 , B(OH) 3 , SnCl 4 ·5H 2 O and amino acid ionic liquid were introduced into D 2 O or DMSO‑ d 6 to explore the tautomer distributions of GlcNAc. The introduction of ZnCl 2 and SnCl 4 ·5H 2 O promoted the conversion of α-pyranose to β-pyranose. The introduction of amino acid ionic liquid has little effect on the percentage of tautomers in D 2 O. However, when the amino acid ionic liquid, such as [Thr]Cl, was introduced into DMSO‑ d 6 , the proportion of β-pyranose increased to 29.06%, compared with no catalyst introduced. Besides, we also studied the tautomer distributions of GlcNAc in commonly utilized reaction solvents for biorefinery, such as N,N -dimethylformamide, N , N -dimethylacetamide, N -methyl-2-pyrrolidinone, ethylene and glycerol. In these solvents, the proportion of β-pyranose in N,N -dimethylformamide and glycerol was reduced to 25.84% and 38.38%, respectively. This study provides the basic experimental data of tautomer distributions of GlcNAc, and guided the conversion and utilization of GlcNAc in the future.
研究领域:
生物化学
·
分析化学
✓ 已验证
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2020
·
IF 3.232
Selvaraj Muthusamy,Kanagaraj Rajalakshmi,Qingxiang Xu,Yan Chen,Long Zhao,Weihua Zhu
Detection of H 2 S to analyze some diseases in living lives demands fast response, high selectivity and biocompatibility. Here we designed an azide containing coumarin attached with 8-aminoquinoline via amide backbone (ACAQ) fluorophore as the H 2 S sensing probe. Excellent response time of 6 min, high sensitivity with the limit of detection (LOD) of 14.6 nM and high selectivity with other possible interferences are revealed for ACAQ after characterized by spectroscopy, 1 H NMR titration and LC–MS measurements. The sensing strategy is explained by amide-iminol tautomerism and azide reduction. In addition, the successful visualization measurement suggests the practicability of the probe ACAQ for H 2 S detection in live samples.
研究领域:
生物化学
·
医学诊断
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULAR PHARMACEUTICS
·
2023
·
IF 4.9
Wen-Juan Ma,Hua-Yu Chen,Yong-Liang Huang,Jia-Mei Chen,Tong-Bu Lu
This study is designed to compare drug encapsulation by cucurbit[7]uril and β-cyclodextrin, using fluorofenidone as a model drug. Single-crystal X-ray diffraction analysis was employed to successfully determine the crystal structures of fluorofenidone·H+@cucurbit[7]uril Form, fluorofenidone@cucurbit[7]uril Form, and fluorofenidone@β-cyclodextrin Form. Keto–enol tautomerization of fluorofenidone mediated by cucurbit[7]uril in acid solution is confirmed by crystal structures, pH titration, and nuclear magnetic resonance experiments. However, β-cyclodextrin cannot cause the keto–enol tautomerization of fluorofenidone under similar conditions. The phase solubility study demonstrates that cucurbit[7]uril has a much higher solubilization capacity for fluorofenidone than β-cyclodextrin in 0.1 M HCl since the Kc values of fluorofenidone with cucurbit[7]uril and β-cyclodextrin were 1223.97 ± 452.68 and 78.49 ± 10.56 M–1, respectively. Excellent solubility can be attributed to the keto–enol tautomerization of fluorofenidone under the conditions of cucurbit[7]uril in acid solution. The enol form of fluorofenidone is encapsulated by cucurbit[7]uril by hydrogen bonding interaction and hydrophobic interaction to increase binding affinity. Rat pharmacokinetic studies demonstrate that the area under the plasma concentration–time curve from time 0 to 7 h value of fluorofenidone@cucurbit[7]uril complex is 1.70-fold greater than that of free fluorofenidone, and the mean residence time from time 0 to 7 h is slightly prolonged from 1.29 to 1.76 h (P < 0.01) after oral administration. However, no significant difference is found between fluorofenidone and fluorofenidone@β-cyclodextrin complex. This work indicates that the induction of keto–enol tautomerization of drugs using macrocyclic molecules has the potential to be an effective method to improve their solubility and bioavailability, providing valuable insights for the application of macrocyclic molecules in the biomedical field.
研究领域:
药学
·
生物化学
·
药物递送系统
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SYNTHESIS-STUTTGART
·
2014
·Vol. 46
·期 05
·621-628
·
IF 2.443
Shengrong Liao,Chun Qin,Peifen Yao,Jinsheng Li,Xuefeng Zhou,Junfeng Wang,Zhishu Huang,Yonghong Liu
A facile and efficient synthesis of novel seven-membered heterocyclic derivatives containing 3-aminoazepan-2-one backbone is described using 1,4-protected piperazine-2,5-diones and alkynes as starting materials. The reaction may undergo Michael addition, unusual nucleophilic attack to an amide group, and keto–enol tautomerization. The reaction showed different reactivity when using substrates with different protecting groups: it had higher efficiency when using either alkanoyl-protecting group with cesium carbonate as the base, or benzoyl-protecting group with triethylamine as the base, but no reaction when using benzyl or allyl protecting groups with a variety of bases (Et3N, DBU, K2CO3, Cs2CO3, KHCO3, CsHCO3, and KOt-Bu).
研究领域:
有机化学
·
药物化学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 25
·期 1
·402-409
·
IF 3.945
Ran Wang,Fengjin Zhang,Xinghang Pan,Xuming Zheng,Jiadan Xue,Yong Du,Binbin Xie
8-Hydroxy-5-nitroquinoline (NO2-QN-OH) is an antimicrobial, anti-inflammatory and anticancer agent, and has been approved for use in the treatment of diseases. Its photosensitivity, however, cannot be overlooked. The photochemistry of 8-hydroxy-5-nitroquinoline in acetonitrile is investigated using transient absorption and time-resolved resonance Raman spectroscopies. By identifying the short-lived intermediates during the photoreaction, it is clear that the Tn state NO2-QN-OH is generated in 0.8 ps via an ultrafast ISC, followed by the IC in 8.5 ps to produce the T1 state. In neat acetonitrile, the T1 state NO2-QN-OH undergoes intramolecular proton transfer and tautomerizes to form T1 state NO2-QNH-O. To our knowledge, this is the first time that the intramolecular excited state proton transfer of hydroxyl-quinolines in an aprotic polar solvent is observed.
研究领域:
光化学
·
物理化学
·
光谱学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）