- Strong hydrogen bonds in 1:1 and 2:1 complexes of pyridine betaine with strong acids
-
The crystal structure of bis(pyridine betaine) hydrochloride-d1, monohydrate-d2 has been determined by X-ray analysis.The carboxylate groups of a pair of pyridine betaine molecules are bridged by a deuteron to form a centrosymmetric dimer featuring a very strong hydrogen bond of length 2.444(4) Angstroem.The geometric mass effect (ΔR ca. 0.008 Angstroem) is well within the range observed for this type of hydrogen bond.The FT-IR spectra of polycrystalline 1:1 and 2:1 complexes of pyridine betaine with HNO3, HCl, HBr, HI, HO3SCF3, HClO4, HBF4, and H2SO4 have been investigated in the 4000-200 cm-1 range.In the 1:1 complexes a proton is transferred from the acid to the betaine molecule, C5H5N+CH2COOH*A-, and both the νOH and νC=O frequencies vary with the proton acceptor properties of the anion.The spectra of the 2:1 complexes show broad and intense O*H*O stretching absorptions in the 1500-200 cm-1 range which are slightly affected by the anion and are similar to that for type A acid salts of carboxylic acids.The skeletal vibrations of the betaine residue were identified by second derivative spectroscopy.Evidence based on the νC=O vibration and deuteration suggests that the hydrogen bonds in +A- are described by single minimum potentials; νH = 940 cm-1, νH/νD = 1.2.As betaines are widely distributed in plants and animal tissue and form complexes with strong hydrogen bonds, such bonds should be formed in biological systems.
- Dega-Szafran, Zofia,Gdaniec, Maria,Grunwald-Wyspianska, Monika,Kowalczyk, Iwona,Szafran, Miroslaw
-
-
Read Online
- Weakly coordinating group directed rhodium-catalyzed unconventional site-selective C–H olefination of indolizines at the 8-position
-
A rhodium-catalyzed directing group promoted selective C–H olefination reaction of indolizines at the 8-position is reported. Di-olefination at 2,8-positions also achieved with silver hexafluoroantimonate as an additive under similar reaction conditions. Weakly coordinating groups, such as ketone, aldehyde, amide and ester, were used as directing groups. The ester group can be removed under acid conditions and therefore is used as a traceless directing group.
- Feng, Xue,Tian, Jiaxin,Sun, Ying,Hu, Huayou,Lu, Mingzhu,Kan, Yuhe,Fang, Danjun,Wang, Chao
-
supporting information
p. 470 - 474
(2020/03/19)
-
- Valorization of chitin derived N-acetyl-D-glucosamine into high valuable N-containing 3-acetamido-5-acetylfuran using pyridinium-based ionic liquids
-
Chitin and its derivatives contain biologically fixed nitrogen elements, which can provide nitrogen sources for N-containing chemicals. Herein, a series of pyridinium-based ionic liquids were synthesized to directly catalyze the conversion of N-acetyl-D-glucosamine (NAG, the monomer of chitin) to 3-acetamido-5-acetylfuran (3A5AF). The yield of 3A5AF in 1-carboxymethyl pyridinium chloride ionic liquid reached 37.49%, without any additives. Using B2O3 and CaCl2 as additives, the optimum yield increased to 67.37% at 180 °C in 20 min. In addition, HPLC-MS analysis has been utilized to elucidate the reaction mechanism. This research on turning “waste” into “wealth” opens up new ways for the utilization of biomass waste, which not only reduces environmental pollution but also has potential economic value.
- Zang, Hongjun,Lou, Jing,Jiao, Shuolei,Li, Huanxin,Du, Yannan,Wang, Jiao
-
-
- Visible-Light-Induced Regioselective Dicarbonylation of Indolizines with Oxoaldehydes via Direct C-H Functionalization
-
A metal-free system for regioselective dehydrogenative cross-couplings between indolizines and oxoaldehydes catalyzed by visible light under mild conditions has been described. As an atom economical and eco-friendly protocol, the reaction proceeds in good yields using inexpensive, readily available visible-light sources and the environmentally friendly oxidant oxygen. Various valuable 1,2-dicarbonyl derivatives attached to an indolizine core were easily accessed by the direct dicarbonylation of the sp2 C-H bond.
- Teng, Lili,Liu, Xiang,Guo, Pengfeng,Yu, Yue,Cao, Hua
-
supporting information
p. 3841 - 3845
(2020/05/08)
-
- Method for preparing 3-hydroxypropionaldehyde by hydrating acrolein
-
The invention relates to a method for preparing 3-hydroxy propionaldehyde by hydrating acrolein. The acrolein is homogeneously catalyzed under the action of a N-heterocyclic carboxylic acid ionic liquid to prepare 3-hydroxy propionaldehyde, wherein the hydration reaction liquid is subjected to aqueous two-phase extraction to recover the ionic liquid catalyst for cyclic utilization. According to the invention, the method is simple to operate and stable in process, the catalyst has very high reaction activity and very good selectivity, and the problems of separation of a homogeneous catalyst andinstability and easy deactivation of a solid catalyst in the hydration process are effectively solved.
- -
-
Paragraph 0049
(2020/12/31)
-
- Indolizine quaternary ammonium salt inhibitors, part III: Insights into the highly effective low-toxicity acid corrosion inhibitor-synthesis and protection performance
-
Three indolizine derivatives (Di-BQC, QM-DiBQC, and PyM-DiBQC), which were prepared facilely in high yield via a 1,3-dipolar cycloaddition reaction, were found to exhibit good corrosion inhibition for steel in concentrated acid without the synergism of propargyl alcohol (PA). The inhibitive derivatives exhibit high protection efficiency and have eco-friendly advantages over the highly toxic PA. The accurate formulas and structures of the three compounds are characterized by high resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy. The corrosion inhibition performance of the indolizine derivatives toward N80 steel was investigated in 15 wt% HCl and 20 wt% HCl by weight loss measurements, electrochemical tests (Tafel and EIS), SEM/EDX analysis and theoretical calculations. The biological toxicity was investigated by using the Microtox toxicity test. At 90 °C, a dosage of 0.1 wt% indolizine derivatives in 15 wt% HCl would decrease the corrosion rate of N80 steel dramatically to less than 10 g m-2 h-1. While for PA, a much higher corrosion rate was observed under the same conditions, indicating that the indolizine derivatives are more effective inhibitors in contrast with PA. Results from gravimetric analysis as well as the electrochemical studies and DFT methods are in good agreement, verifying the fine corrosion prevention of the three compounds. The results of biotoxicity tests confirmed the relatively low-toxicity properties of the indolizine derivatives and the suggested inhibition mechanism was also discussed. All the conclusions above indicate that the new indolizine derivatives could be presented as highly effective acidizing inhibitors and the derivatives may offer a new enlightening strategy for corrosion protection under acidizing conditions.
- Yang, Zhen,Wang, Yefei,Zhan, Fengtao,Chen, Wuhua,Ding, Mingchen,Qian, Cheng,Wang, Renzhuo,Hou, Baofeng
-
p. 18461 - 18475
(2019/12/09)
-
- Acidification corrosion inhibitor based on interpolymer indolizine derivative as well as preparation method and application thereof
-
The invention discloses an acidification corrosion inhibitor based on an interpolymer indolizine derivative as well as a preparation method and application thereof. The acidification corrosion inhibitor contains the interpolymer indolizine derivative; the interpolymer indolizine derivative is prepared by carrying out decarboxylation on heterocyclic alkali including (substituted) quinoline, (substituted) pyridine and the like, and carboxymethyl heterocyclic alkali quaternary ammonium salt obtained by alpha-haloacetic acid, and then carrying out intermolecular addition polymerization reaction onquaternary ammonium salt of the heterocyclic alkali including the (substituted) quinoline, the (substituted) pyridine and the like. The acidification corrosion inhibitor disclosed by the invention has relatively good corrosion inhibition performance under the condition that common corrosion inhibition synergists including alkynol and the like do not need to be compounded; the use amount of the acidification corrosion inhibitor is less and the acidification corrosion inhibitor can reach, even be better than the requirements of an acidification corrosion inhibitor performance testing method andfirst-grade to third-grade standards in evaluation indexes SY/T 5405-1996 when being independently used.
- -
-
Paragraph 0031
(2018/09/12)
-
- Cyclocondensation-Knoevenagel–Michael Domino reaction of phenyl hydrazine, acetoacetate derivatives and aryl aldehydes over acetic acid functionalized ionic liquid
-
Abstract: An efficient solvent-free protocol for the synthesis of 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s via one-pot pseudo five-component condensation reaction of phenyl hydrazine, ethylacetoacetate, and aryl aldehydes in the presence of acetic acid functionalized pyridinium salt (1-(carboxymethyl)pyridinium chloride {[cmpy]Cl}) as reusable catalyst has been reported. Moreover,1 H and13C NMR, mass, CHN analysis, Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction analysis, and calculation of interplaner distance of the catalysts have been studied in this work. Graphical Abstract: [Figure not available: see fulltext.]
- Moosavi-Zare, Ahmad Reza,Zolfigol, Mohammad Ali,Noroozizadeh, Ehsan,Khaledian, Omid,Shaghasemi, Behzad Shirmardi
-
p. 4759 - 4772
(2016/07/06)
-
- INDOLIZINE DERIVATIVE AND USE THEREOF FOR MEDICAL PURPOSES
-
The present invention provides compounds useful as agents for the prevention or treatment of a disease associated with abnormal serum uric acid level and the like. That is, the present invention relates to indolizine derivatives represented by the following formula (I) having xanthine oxidase inhibitory activities and useful as agents for the prevention or treatment of a disease associated with abnormality of serum uric acid level, prodrugs thereof, salts thereof or the like. In the formula, ring U represents aryl or heteroaryl; R1 represents halogen, a hydroxy group or the like; R2 represents halogen, a hydroxy group, alkyl, alkoxy, alkyl substituted by fluorine, alkoxy substituted by fluorine or the like; m represents a number from 0 to 2; n represents a number from 0 to 3; and R3 represents hydrogen, fluorine or the like.
- -
-
Page/Page column 11
(2012/02/01)
-
- Predictable and site-selective functionalization of poly(hetero)arene compounds by palladium catalysis
-
The challenge of achieving selective and predictable functionalizations at C-H bonds with complex poly(hetero)aromatic substrates was addressed by two different approaches. Site-selectivity can be obtained by applying various reaction conditions that are (hetero)arene specific to substrates that contain indoles, pyridine N-oxide, and polyfluorinated benzenes. An experimental classification of electron-rich heteroarenes based on their reactivity toward palladium-catalyzed C-Hfunctionalization was established, the result of which correlated well with the order of reactivity predicted by the DFT-calculated concerted metalation-deprotonation (CMD) pathway. Model substrates containing two reactive heteroarenes were then reacted under general reaction conditions to demonstrate the applicability this reactivity chart in predicting the regioselectivity of the palladium-catalyzed direct arylation and benzylation reactions.
- Lapointe, David,Markiewicz, Thomas,Whipp, Christopher J.,Toderian, Amy,Fagnou, Keith
-
experimental part
p. 749 - 759
(2011/04/16)
-
- Synthesis of indolizine derivatives with selective antibacterial activity against Mycobacterium tuberculosis
-
1-Substituted indolizines with activity against Mycobacterium tuberculosis have been synthesized. The most active compounds carry an hydroxyphenylmethyl- or hydroxyalkyl substituent in the indolizine 1-position. The alkyl chain should be moderately long (C-5 or C-6). Aryl groups in the 2- and 3-position of the indolizine are also required. Removal of the 3-substituent resulted in significant loss of activity. A nitrile substituent in the 7-position is beneficial for both chemical stability and bioactivity. The compounds studied display a narrow antibacterial spectrum and appear to be quite selective antimycobacterial compounds. Moderate activity against certain pathogenic protozoa was also observed.
- Gundersen, Lise-Lotte,Charnock, Colin,Negussie, Ayele Hailu,Rise, Frode,Teklu, Solomon
-
-
- Soft antimicrobial agents: Synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds
-
A series of soft quaternary ammonium antimicrobial agents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 μg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of 10μg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 °C.
- Thorsteinsson, Thorsteinn,Másson, Már,Kristinsson, Karl G.,Hjálmarsdóttir, Martha A.,Hilmarsson, Hilmar,Loftsson, Thorsteinn
-
p. 4173 - 4181
(2007/10/03)
-
- A novel and practical synthesis of 3-unsubstituted indolizines
-
A novel and practical procedure for the preparation of 3-unsubstituted indolizines by 1,3-dipolar cycloaddition was developed. The requisite pyridinium N-methylides were generated simply from the corresponding N-(carboxymethyl)pyridinium halides. In the presence of MnO2, electron-deficient alkenes, instead of alkynes or vinyl bromides, were used successfully as dipolarophiles. This general method features cheap reagents, simple workup procedure and gives the products in moderate to high yields (57-92%).
- Zhang,Liang,Sun,Hu,Hu
-
p. 1733 - 1737
(2007/10/03)
-
- A versatile Synthesis of Carboxypyridine Betaines and their 1H and 13C NMR Spectra
-
Pyridine betaine and 15 substituted pyridine betaines were prepared by alkylation of R-pyridines with ethyl chloroacetate.The ester group was removed by acid hydrolysis and the obtained hydrochlorides were left with propylene oxide in order to obtain pure, free R-pyridine betaines.The 1H and 13C NMR spectra of free betaines and their hydrochlorides were analysed with respect to an interaction of the ring substituents with N+CH2COO group. - Key words: R-pyridine betaines; ethyl chloroacetate; propylene oxide; IR spectra; 1H and 13C NMR spectra.
- Dega-Szafran, Zofia,Kowalczyk, Iwona,Szafran, Miroslaw
-
p. 303 - 312
(2007/10/03)
-
- Diazepines. Part 25. Preparation and Properties of 6-Aryl-2,3-dihydro-1,4-diazepinium Salts. Electronic Interaction between the Rings and Steric Inhibition thereof
-
A variety of 6-aryldihydrodiazepinium salts (including also 6-biphenyl-4-yl, 6-α-naphthyl, and 6-N-pyridyl) has been prepared, mostly by reactions of 1,2-diamines with 3-aryl-1,5-diazapentadienium salts.The electron-rich dihydrodiazepinium cation activates the 6-aryl substituent towards electrophilic attack, and halogenation and nitration take place at the p-position.Substituents vicinal to the ring junction in either the six- or seven-membered rings inhibit this reactivity, presumably by preventing coplanarity of the two rings; the 13C n.m.r. spectra of these vicinally substituted compounds also show the lowered electronic interactions between the rings.NN'-diphenyl and NN'-dibenzyl substituents also inhibit electrophilic substitution in the 6-phenyl ring.Solution in deuteriosulphuric acid generates a stable radical species.Nucleophiles (monoamines, diamines, sodium hydroxide) attack the 5- and 7-positions of the diazepine ring.The 13C n.m.r. and mass spectra of these compounds are discussed.
- Lloyd, Douglas,Tucker, Kanwaljit S.,Marshall, Donald R.
-
p. 726 - 735
(2007/10/02)
-