- Thiourea-Mediated Halogenation of Alcohols
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The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
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p. 12901 - 12911
(2020/11/26)
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- Glycol-functionalized ionic liquids for high-temperature enzymatic ring-opening polymerization
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Enzymatic ring-opening polymerization (ROP) is a benign method for preparing polyesters, such as polylactides and other polylactones. These reactions are typically carried out at relatively high temperatures (60-130 °C), however, there is a deficiency of enzyme-compatible solvents for such thermally-demanding biocatalytic processes. In this study, we have prepared a series of short-chained glycol-grafted ionic liquids (ILs) based on a phosphonium, imidazolium, pyridinium, ammonium, or piperidinium cationic headgroup. Most of these glycol-grafted ILs exhibit relatively low dynamic viscosities (33-123 mPa s at 30 °C), coupled with excellent short-term thermal stabilities with decomposition temperatures (Tdcp) in the 318-403 °C range. Significantly, the long-term thermal stability under conditions matching those for enzymatic ROP synthesis (130 °C for 7 days) is excellent for several of these task-specific ILs. Using Novozym 435-catalyzed ROP, these ILs are demonstrated to be viable solvents for the enzymatic production of reasonable yields (30-48%) of high molecular mass (Mw ～20 kDa) poly(l-lactide) and poly(?-caprolactone) compared to solventless conditions (12-14 kDa).
- Zhao, Hua,Afriyie, Lennox O.,Larm, Nathaniel E.,Baker, Gary A.
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p. 36025 - 36033
(2018/11/20)
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- THIAZOLIDINONE COMPOUNDS AND USE THEREOF
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A pharmaceutical composition containing a compound of Formula (I) for treating an opioid receptor-associated condition. Also disclosed is a method for treating an opioid receptor-associated condition using such a compound. Further disclosed are two sets of thiazolidinone compounds of formula (I): (i) compounds each having an enantiomeric excess greater than 90% and (ii) compounds each being substituted with deuterium.
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Paragraph 1254-1255
(2017/09/21)
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- Regioselective Synthesis of 2-Amino-5-(or 3-)arylazo-Substituted Pyridines and Pyrazines from Pyridinium N-Aminides
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Differently modified 2-aminopyridines and pyrazines bearing an arylazo group at the 3- or 5-position have been generated from pyridinium N-aminides in a regioselective fashion. The detailed chemistry starts with attack of the N-aminide on a diazonium salt, to form the arylazo derivative. N-alkylation on the exocyclic nitrogen and reduction to break the N-N bond then affords the final compounds, as an extension of the broad synthetic uses of the pyridinium N-aminides.
- Gala, Elena,Reyes, M. José,Alvarez-Builla, Julio,Izquierdo, M. Luisa
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p. 2145 - 2156
(2016/05/09)
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- SYNTHESIS OF DIFUNCTIONAL OXYETHYLENE-BASED COMPOUNDS
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A method of reacting a toluenesulfonyl-terminated polyoxyethylene compound having the formula CH3—C6H4—SO2—(O—CH2—CH2)n—O—R1 with an ammonium salt having the formula NR24X to form a compound having the formula X—CH2—CH2—(O—CH2—CH2)n-1—R3. The value n is a positive integer. X is a halogen, cyanide, cyanate, thiocyanate, or azide. R1 is a terminating group. Each R2 is hydrogen or an alkyl group. —R3 is —O—R1 or —X.
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Page/Page column 2-3
(2009/07/25)
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- Functionalized hydrophobic and hydrophilic self-assembled supramolecular rectangles
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(Figure Presented) The synthesis of six new, functionalized 180° pyridyl donor ligands and their coordination-driven self-assembly into supramolecular rectangles is reported. Three of the new donors have been functionalized with hydrophobic straight chain alkane units (C6, C12, and C18) while the remaining three have been functionalized with derivatized di-, tetra-, and hexaethylene glycol hydrophilic units (DEG, TEG, and HEG, respectively). The resulting self-assembled hydrophobic and hydrophilic supramolecular rectangles have been fully characterized by multinuclear NMR and electrospray ionization mass spectrometry. Molecular force field modeling suggests that the functionalized rectangles range in size from roughly 3.0 x 2.9 to 3.0 x 6.0 nm2 in size.
- Northrop, Brian H.,Gloeckner, Andreas,Stang, Peter J.
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p. 1787 - 1794
(2008/09/18)
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- Practical use of NH4X salts for difunctional oxyethylene-based intermediates
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A series of tosyl functionalized oxyethylene-based organic compounds were selected to analyze the scope and efficiency of a general substitution method for conversion to difunctional, soluble oxyethylene based intermediates using readily available ammonium salts, glycols and commercially modified ethoxy-ethanols. Straightforward preparation, product purification and low cost reagents are particularly advantageous for compounds incorporating halides, thiocyanates and methoxy groups.
- Holmes, Brian T.,Snow, Arthur W.
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p. 4813 - 4815
(2008/02/05)
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- LB film structure of poly(2-methoxy,5-(8-methoxy-3,6-dioxa-1-undecoxy)-p-phenylene vinylene) studied by spectroscopy
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A PPV derivative, poly(2-methoxy,5-(8-methoxy-3,6-dioxa-1-undecoxy)-p-phenylene vinylene), has been synthesized by the Gilch route to study the influence of a long alkyl side chain and a di(ethylene oxide) methyl ether group on the multilayer structure obtained by Langmuir-Blodgett (LB) technique. UV-visible, PL, and FTIR spectra are applied to study the conformation and orientation of the MMDU-PPV molecules in multilayer organization. MMDU-PPV is apt to form a transferable monolayer film, in which the plane of its π system is perpendicular to the air-water interface. The adjacent conjugated main chains of MMDU-PPV in LB films are aligned in parallel fashion and packed with the plane of its π system approximately perpendicular to the layer plane and not organized to compact π-stacking structure for introducing di(ethylene oxide) methyl ether (DEOM) side chains to conjugated main chains. The long alkyl side chains are characterized by all trans-zigzag conformation and average tilt angle of 36±1.5°. The layer-by-layer multilayer of MMDU-PPV obtained by Langmuir-Blodgett technique exhibits some in-plane anisotropy and more pure photoluminescence than that of the dilute MMDU-PPV solution.
- Wu, Zhongkui,Wu, Sanxie,Liang, Yingqiu
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p. 1631 - 1641
(2007/10/03)
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- Conversion of alcohols to thiols via tosylate intermediates
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High yielding syntheses of mercapto terminated mono-disperse dimer, trimer, and tetramer ethyleneoxide oligomers and of p-hydroxyphenethyl thiol via an alcohol-tosylate-thiol route are reported. Comparisons are made with the more conventional alcohol-bromide-thiol route.
- Snow, Arthur W.,Foos, Edward E.
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p. 509 - 512
(2007/10/03)
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- Adsorbed surfactants for affinity chromatography: End-group modification of ethylene glycol polymers
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The hydroxyl end-groups of PluronicF108 {a tri-block copolymer surfactant of poly(ethylene glycol) and poly(propylene glycol) [PEG-PPG-PEG]} were converted into primary amine and quaternary ammonium equivalents for use in a new approach to affinity chromatography. The preparation of sulphonic acid end-groups was also attempted.
- Yanic, Cemile,Bredenkamp, Martin W.,Jacobs, Edmund P.,Swart, Pieter
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p. 1381 - 1384
(2007/10/03)
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- Design, Synthesis, and Structure-Activity Relationship Studies for a New Imidazole Series of J774 Macrophage Specific Acyl-CoA:Cholesterol Acyltransferase (ACAT) Inhibitors
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Acyl-CoA:cholesterol acyltransferase (ACAT) is the primary enzyme involved in intracellular cholesterol esterification.Arterial wall infiltration by macrophages and subsequent uncontrolled esterification of cholesterol leading to foam cell formation is believed to be an important process which leads to the development of fatty streaks.Inhibitors of the ACAT enzyme may retard this atherogenic process.We have recently discovered a series of imidazoles which are potent in vitro ACAT inhibitors in the J774 macrophage cell culture assay.This paper will describe the design, synthesis, and structure-activity relationship for this very potent series of compounds.
- Maduskuie, Thomas P.,Wilde, Richard G.,Billheimer, Jeffrey T.,Cromley, Debra A.,Germain, Sandra,et al.
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p. 1067 - 1083
(2007/10/02)
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- Platinum(II) complexes, their preparation and use as anti-tumor agents
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Compounds of formula I STR1 wherein R1 and R2, that can be the same or different, are hydrogen, alkyl, aryl, aralkyl groups or, if taken together, cycloalkyl groups; A is a carbon atom, a residue of 2,3-dioxybutandioic-2,4-dioxyphtalic acid or disubstituted malonic acid derivatives; n1 and n2 are selected in such a manner that the result of their addition is from 2 to 40; T1 and T2 that can be the same or different, are hydrogen, alkyl, benzyl, phenyl, acyl or cycloalkyl or a residue of formulae STR2 Compounds I are useful as anti-tumor agents in human therapy.
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