Hydroxyalkyl Groups Research Articles

Hypercoordinate Germanium Complexes with Ligands Containing Hydroxyalkyl Groups

Hypercoordinate Germanium Complexes with Ligands Containing Hydroxyalkyl Groups

Hypercoordinated germanium complexes with ligands containing hydroxyalkyl groups

Among germatranes, 1-germatranol hydrate is the most well-studied compound with a diverse spectrum of biological activity. Its synthesis is based on a one-stage reaction of tris(2-hydroxyethyl)amine with germanium dioxide in an aqueous medium without the use of organic solvents. In this work, taking into account this approach, new potentially biologically active compounds of germanium with hydroxyalkylamines, sulfo- and amino acids containing hydroxyalkyl groups were synthesized, which we considered as new analogues of biologically active 1-germatranol hydrate. Their formation is confirmed by the results of elemental analysis, IR and NMR spectroscopy. In silico ADME and Pass analysis were used to assess the potential bioavailability and pharmacological activity profile of new compounds. The results of an in vitro study of the antiviral activity (influenza A/Aichi/2/68 (H3N2) virus) of synthesized compounds are presented.

Cytokinin oxidase/dehydrogenase inhibitors: outlook for selectivity and high efficiency

Inhibitors of cytokinin oxidase/dehydrogenase (CKX) reduce the degradation of cytokinins in plants, and this effect can be exploited in agriculture and in plant tissue culture. In this study, we examine the structure-activity relationship of two series of CKX inhibitors based on diphenylurea. The compounds of Series I were derived from the recently published CKX inhibitors 3TFM-2HM and 3TFM-2HE, and we identified key substituents with increased selectivity for maize ZmCKX1 and ZmCKX4a over AtCKX2 from Arabidopsis. Series II contained compounds that further exceled in CKX inhibitory activity as well as in the ease of their synthesis. The best inhibitors exhibited half-maximal inhibitory concentration (IC50) values in low nanomolar ranges with ZmCKX1 and especially with ZmCKX4a, which is generally more resistant to inhibition. The activity of the key compounds was verified in tobacco and lobelia leaf-disk assays, where N6-isopentenyladenine was protected from degradation and promoted shoot regeneration. All the prepared compounds were further tested for toxicity against Caenorhabditis elegans, and the assays revealed clear differences in toxicity between compounds with and without a hydroxyalkyl group. In a broader perspective, this work increases our understanding of CKX inhibition and provides a more extensive portfolio of compounds suitable for agricultural and biotechnological research.

Synthesis of (Hyper)Branched Monohydroxyl Alkoxysilane Oligomers toward Silanized Urethane Prepolymers.

The aim of this work was the synthesis of (hyper)branched oligomers based on trialkoxysilane in various conditions and further application of them in order to modify the urethane prepolymers. Hydroxyl-terminated trialkoxysilane was used as a monomer for homo-condensation. It was obtained by reaction of 3-aminopropyl trialkoxysilane (APTES) with ethylene carbonate (EC). The reaction was based on the attack of amine at the carbonyl carbon atom followed by ring opening of the carbonate to give a urethane (carbamate) product. The next step was the condensation via substitution of ethoxy groups on silicon atom with the terminal hydroxyalkyl groups present in the primary product with the evolution of ethanol. Accordingly, the impact of temperature and type of catalyst on process efficiency was investigated. A quantitative analysis of reaction progress and products of the conversion of EC together with ethanol evolution was conducted by means of gas chromatography, which allowed us to determine the formation of monomeric product and, indirectly, of oligomeric products. It was found that at room temperature after 24 h, the majority of the monomeric product was isolated, whereas at elevated temperature in the presence of Ti-based catalyst, further condensation of the monomer into branched oligomers was preferred, and, moreover, the application of vacuum intensified that process. The obtained products were structurally characterized by 1H and 29Si NMR, MALDI-ToF and Gel Permeation Chromatography. Finally, two different alkoxysilane products, monomeric and oligomeric, were applied for modification of urethane prepolymer, forming silanized one (SPUR). The influence of the silanizing agent on the mechanical and thermal properties of the moisture-cured products was shown before and after additional conditioning in water.

N‐Sulfanylimides as the Sulfur Source for Alkyl Allenyl Sulfoxides via [2,3]‐Sigmatropic Rearrangement

AbstractSulfenyl chlorides are a reliable starting material to access allenyl sulfoxides with aryl or haloalkyl groups by way of sulfenate ester formation followed by [2,3]‐sigmatropic rearrangement. Application of the chemistry of alkanesulfenyl chlorides is much less common due to competing fates along the reaction pathway. In this paper, N‐sulfanylsuccimides (thiosuccinimides) are shown to be a viable replacement for sulfenyl chlorides. A number of allenyl alkyl sulfoxides are prepared in fair to good yields (21–73 %, 21 examples). In addition, some butyn‐1,4‐diols can be selectively monofunctionalized to form allenyl sulfoxides (26–71 %) with a hydroxyalkyl group geminal to the sulfur. Butynediols also permit synthetic access to dienes via successive sulfenate ester formation and [2,3]‐sigmatropic rearrangement reactions. N‐2‐Trimethylsilylethylthosucinimides were among the highest yielding of the thioimides.

Reactive modified curcumin for high-fastness nonaqueous SC-CO2 dyeing of cotton fabric

Modified curcumin, which has the advantages of low toxicity, high solubility, and little color change after modification, is very suitable for nonaqueous supercritical carbon dioxide cotton dyeing. However, the existing curcumin modification technology focuses on improving its solubility. Modified curcumin is directly adsorbed onto cotton fabrics, and the main interaction forces are van der Waals forces, which causes the poor fastness of modified curcumin to dyed cotton fabrics. In this study, reactive groups (hydroxyalkyls) were introduced into curcumin to enhance its fastness to cotton fabrics. The results showed that, similar to alkyl groups, hydroxyalkyl groups can enhance the color depth of dyed cotton fabrics by elevating the solubility of modified curcumin in supercritical carbon dioxide. The higher the solubility of modified curcumin in supercritical carbon dioxide was, the higher the K/S value of the dyed cotton fabric. Furthermore, the hydroxyl groups on the modified curcumin could form ether bonds with the hydroxyl groups on cotton fabrics. Therefore, the washing and rubbing fastness of hydroxyalkyl-curcumin-dyed cotton fabric was better than that of alkyl-curcumin-dyed cotton fabric.

Uncovering the potentialities of protic ionic liquids based on alkanolammonium and carboxylate ions and their aqueous solutions as non-derivatizing solvents of Kraft lignin

The present study scrutinized in depth the ability of alkanolammonium-based Protic Ionic Liquids (PILs) with carboxylate anions to dissolve Kraft lignin at 323.15 K. A focus was put on understanding the role of both PIL ions and water on the dissolution process. The results demonstrated that the anion plays a more important role in lignin dissolution than the cation. Furthermore, lignin dissolution was favored by increasing the alkyl chain of the carboxylate anion, while a smaller cation with lower number of hydroxyalkyl groups performed better. Among the studied solvents, the 2-hydroxyethylammonium hexanoate (HEAH) displayed the highest lignin solubility (37 wt%). In general, the addition of water had a negative influence on lignin solubility with the tested PILs. A sharp decrease in lignin solubility curves of 2-hydroxyethylammonium formate (HEAF) and acetate (HEAA) was observed, while a more softly effect was observed for 2-hydroxyethylammonium propionate (HEAP) and HEAH with the addition of water. However, a distinct behavior was observed for 2-hydroxyethylammonium octanoate (HEAO) that acted as hydrotrope enhancing lignin solubility in aqueous solutions to a maximum value at 40 wt% water content. Furthermore, by increasing the temperature, the lignin solubility was favored due to endothermic behavior of lignin dissolution process.The dissolution of Kraft lignin was also performed at 393.15 K to unravel any lignin modification unleashed by PILs. GPC, FTIR-ATR and 2D NMR were employed for lignin characterization and the changes observed between native lignin and recovered lignin samples were negligible demonstrating the non-derivatizing character of the PILs. Moreover, the recycle of 2-hydroxyethylammonium propionate (HEAP) was successfully demonstrated for at least 3 cycles. In this way, PILs are herein revealed as promising solvents to apply in lignin valorization towards more efficient and eco-friendly processes.

A Novel Natural Dye Derivative for Natural Fabric Supercritical Carbon Dioxide Dyeing Technology

The supercritical carbon dioxide (SC-CO2) dyeing technology is a green dyeing technology, and the usage of natural dye makes SC-CO2 dyeing technology safer and more environment-friendly. Nevertheless, after using natural dye in SC-CO2 dyeing, the color depth and fastness of dyed natural fabric are poor. In this study, alkyl and hydroxyalkyl groups were grafted onto alizarin, which is a natural dye, to elevate the color depths and fastness of alizarin-derivative-dyed natural fabric. The results demonstrate that the color depths of alkyl-alizarin-dyed and hydroxyalkyl-alizarin-dyed natural fabrics were increased. This has to do with the increase in the solubilities of alkyl alizarin and hydroxyalkyl alizarin in SC-CO2. The hydroxybutyl-alizarin-dyed wool displayed the best color depth (K/S value: 6.44). And the hydroxyalkyl-alizarin-dyed natural fabric showed good washing fastness and rubbing fastness (about 4–5 level), because that hydroxyalkyl alizarin could be linked by a covalent bond to the natural fabric.

Synthetic Toll-like Receptors 7 and 8 Agonists: Structure-Activity Relationship in the Oxoadenine Series.

Toll-like receptors 7 and 8 (TLR7/8) are broadly expressed on antigen-presenting cells, making TLR7/8 agonists likely candidates for the development of new vaccine adjuvants. We previously reported the synthesis of a new series of 8-oxoadenines substituted at the 9-position with a 4-piperidinylalkyl moiety and demonstrated that TLR7/8 selectivity and potency could be modulated by varying the length of the alkyl linker. In the present study, we broadened our initial structure–activity relationship study to further evaluate the effects of N-heterocycle ring size, chirality, and substitution on TLR7/8 potency, receptor selectivity, and cytokine (IFNα and TNFα) induction from human peripheral blood mononuclear cells (PBMCs). TLR7/8 activity correlated primarily to linker length and to a lesser extent to ring size, while ring chirality had little effect on TLR7/8 potency or selectivity. Substitution of the heterocyclic ring with an aminoalkyl or hydroxyalkyl group for subsequent conjugation to phospholipids or antigens was well tolerated with the retention of both TLR7/8 activity and cytokine induction from human PBMCs.

Effects of head group on the properties of cationic surfactants containing hydroxyethyl- and hydroxyisopropyl fragments

Cationic surfactants containing different head-groups have been synthesized by interaction of tetradecyl bromide and amines having hydroxyalkyl group (monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, diethanolisopropanolamine, ethanoldiisopropanolamine, triisopropanolamine). Surfactivity parameters of the synthesized cationic surfactants have been determined by measurements of surface tension and electroconductance. The character of change of the colloidal-chemical parameters with an increase of the number of hydroxyethyl and hydroxyisopropyl groups in the head-group of the cationic surfactants has been established. The synthesized cationic surfactants possess effective antibacterial and antifungal properties.

A Study about Regioisomeric Hydroquinones with Multiple Intramolecular Hydrogen Bonding.

A theoretical exploration about hydrogen bonding in a series of synthetic regioisomeric antitumor tricyclic hydroquinones is presented. The stabilization energy for the intramolecular hydrogen bond (IHB) formation in four structurally different situations were evaluated: (a) IHB between the proton of a phenolic hydroxyl group and an ortho-carbonyl group (forming a six-membered ring); (b) between the oxygen atom of a phenolic hydroxyl group and the proton of an hydroxyalkyl group (seven membered ring); (c) between the proton of a phenolic hydroxyl group with the oxygen atom of the hydroxyl group of a hydroxyalkyl moiety (seven-membered ring); and (d) between the proton of a phenolic hydroxyl group and an oxygen atom directly bonded to the aromatic ring in ortho position (five-membered ring). A conformational analysis for the rotation around the hydroxyalkyl substituent is also performed. It is observed that there is a correspondence between the conformational energies and the IHB. The strongest intramolecular hydrogen bonds are those involving a phenolic proton and a carbonyl oxygen atom, forming a six-membered ring, and the weakest are those involving a phenolic proton with the oxygen atom of the chromenone, forming five-membered rings. Additionally, the synthesis and structural assignment of two pairs of regioisomeric hydroquinones, by 2D-NMR experiments, are reported. These results can be useful in the design of biologically-active molecules.

Organometallic Nucleoside Analogues: Effect of Hydroxyalkyl Linker Length on Cancer Cell Line Toxicity

A new series of chiral ferrocene derivatives containing both a hydroxyalkyl group and a thyminyl group on one cyclopentadienyl ring have been synthesised to probe structure–activity relationships in cancer cell line cytotoxicities. The stereoisomers of enantiomeric pairs of these so‐called ferronucleosides have been studied and characterised by a combination of chiral analytical HPLC and single‐crystal X‐ray diffraction. Biological activity studies revealed that changing the length of the hydroxyalkyl group had marked effects on IC50 values, with compounds having shorter arms that more closely resemble endogenous nucleosides exhibiting lower cytotoxicities. The lipophilicities and electrochemical properties of this compound series have been studied to rationalise these trends and indicate future directions of study.

Dinuclear Cu(II) complexes of compartmental Schiff base ligands formed from unsymmetrical tripodal amines of varying arm lengths: Crystal structure of [Cu2L1](ClO4)2 and theoretical studies

Three new dinuclear copper complexes were synthesized via condensation reaction of three new unsymmetrical N-capped tripodal amines and 2,6-diformyl-4-methylphenol, in the presence of copper(II) perchlorate. The solid-state structure of the dinuclear complex, [Cu2L1](ClO4)2, has been determined by X-ray crystallography, showing that the CuII centers have distorted square-pyramidal geometry with N3O2 coordination. The copper (II) ions are bridged by phenolic and hydroxyalkyl groups when in both cases, deprotonation of the hydrogen atoms of the OH groups occurs. The distance between the copper atoms is 3.062 Å. This compound consists of the dication [Cu2L1]2+ and two ClO4− anions in which one of ClO4− groups has a week interaction with one of the Cu atoms. All complexes were characterized by a variety of physico-chemical techniques such as elemental analyses, IR, mass spectra, conductivity measurements and electronic spectral studies. Computational investigation of mentioned binuclear Cu(II) complexes was done by using M062X method with LANL2DZ basis set in vacuo.

Synthesis of polysiloxane-based quaternized imidazolium salts with a hydroxy group at the end of alkyl groups

A series of polysiloxane derivatives having quaternized imidazolium moieties with hydroxyalkyl groups ([HPImnOH]Xs) (where n is the number of methylene group and X is counter anion) were prepared by quaternization of poly(3-chloropropylmethylsiloxane) (P1) using 1-(ω-hydroxyalkyl)imidazole derivatives (ImnOHs) and anion-exchange reaction using lithium bis(trifluoromethanesulfonyl)imide. Polysiloxane-based quaternized imidazolium salts having hydroxyalkyl groups with chloride anion ([HPImnOH]Cls) were obtained with high quaternization ratio of approximately 100mol%. The glass transition temperatures (Tgs) of [HPImnOH]Xs were reduced by introducing a hydroxy group at the end of alkyl groups; however, no significant reduction in Tgs was observed by anion exchange from chloride anion to bis(trifluoromethanesulfonyl)imide one (Tf2N−).

Structure-Binding Effects: Comparative Binding of 2-Anilino-6-naphthalenesulfonate by a Series of Alkyl- and Hydroxyalkyl-Substituted β-Cyclodextrins.

Cyclodextrins (CDs) are the most widely used organic hosts for the inclusion of guest molecules. CDs can be readily modified through substitutions of the hydroxyl groups, and these modified CDs can have different host binding properties compared to those of parent CDs. However, only relatively few systematic studies of the effects of chemical substitution on CD binding ability have been reported thus far. In this paper, we report the study of the binding properties of five different analytically pure modified β-cyclodextrin (β-CD) hosts (substituted with alkyl and/or hydroxyalkyl groups) with 2-anilino-6-naphthalenesulfonate (2,6-ANS) as guest. Binding constants for the formation of the inclusion complex between 2,6-ANS and each CD were determined using both fluorescence spectroscopy and capillary electrophoresis. Addition of modified CDs to an aqueous solution of 2,6-ANS resulted in significant enhancement of the fluorescence intensity of 2,6-ANS, as well as a significant spectral blue shift, indicative of inclusion. Inclusion of 2,6-ANS within the CD cavity was confirmed by NMR spectroscopy. Substitution at position 3 decreased the magnitude of the binding constants, while alkyl or hydroxylalkyl substitution of the primary hydroxyl at position 6 increased the magnitude of the binding constant in all cases, in relation with increasing length of the alkyl chain linker. In addition, binding constants decreased with solvent polarity when increasing amounts of methanol were added. Structure-binding correlations for CDs based on these binding constant results are presented and discussed.

곁가지에 다양한 길이의 알코올 그룹을 지닌 고분자들의 저임계 용액온도 민감성 제어

하이드록시 그룹을 지닌 온도민감형 고분자들이 원자전이라디칼중합법(ATRP)과 클릭반응(click reaction)에 의해 합성되어졌다. 고분자들의 분자량과 분자량 분포도는 gel permeation chromatography(GPC)에 의하여 얻어졌고, 고분자들의 분자량은 잘 제어되었으며 분자량 분포도도 낮게 유지되었다. 클릭반응의 효율은 <TEX>$^1H$</TEX> NMR spectroscopy에 의해 얻어졌으며, 높은 효율을 나타내었다. 고분자 사슬 곁가지의 아민 그룹의 종류와, 치환된 알코올 그룹의 종류에 따라 저임계 용액 온도(LCST)의 제어가 가능했다. Thermoresponsive polymers were successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized by ATRP, followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-alkyne. Homopolymers having secondary amine groups, tertiary amines with hydroxyethyl and hydroxypropyl groups were synthesized by adding 2-azido-N-ethyl-ethanamine, 2-[(2-azidoethyl)amino]ethanol, and 2-[(2-azidoethyl)amino]propanol, respectively, to the PHEMA-alkyne backbone using click chemistry. Molecular weight (MW), molecular weight distribution (MWD), and click reaction efficiency were determined by gel permeation chromatography (GPC) and <TEX>$^1H$</TEX> NMR spectroscopy. The transmission spectra of the 1.0 wt% aqueous solutions of the resulting polymers at 650 nm were measured as a function of temperature. Results showed that the lower critical solution temperature (LCST) could be easily controlled by the length of the hydroxyalkyl groups.

Synthesis, structure, and catalytic activity of new aluminum complexes formed with sterically bulky ligands

A reaction of pyridine related ligands containing two hydroxyalkyl groups, 2,6-(HO-Z-CH2)2C5H3N (Z is 1,1-cyclohexylene, 2,2-adamantylene) with trimethylaluminum and trimethoxyaluminum leads to three new aluminum complexes with the Me-Al or MeO-Al bond: 2,6-C5H3N(CH2-Z-O)2Al-X (Z is 1,1-cyclohexylene, X = Me (5), OMe (6); Z is 2,2-adamantylene, X = Me (7)). The structures of new derivatives were confirmed by NMR spectroscopy and elemental analysis. The structure of complex 5 was studied by X-ray diffraction analysis. Complex 5 is a dimer in the solid state due to the formation of a four-membered ring...Al-O...Al-O.... Complexes 5 and 6 were studied as initiators of the ring-opening polymerization of e-caprolactone.

Diastereoselective Synthesis of Tetrahydrofurano‐ and Tetrahydropyrano‐dihydropyrroles Containing N,O‐Acetal Moieties via Rhodium‐Catalyzed Transannulation of N‐Sulfonyl‐1,2,3‐triazoles with Oxacycloalkenes

AbstractDiastereoselective synthesis of tetrahydro‐furanodihydropyrroles and tetrahydropyranodihydropyrroles containing N,O‐acetal moieties is reported via rhodium‐catalyzed denitrogenative transannulation of N‐sulfonyl‐1,2,3‐triazoles with oxacycloalkenes. A multitude of functionalized pyrroles possessing hydroxyalkyl group at C3‐position could be prepared via Rh‐catalyzed denitrogenative transannulation/acid‐catalyzed ring‐opening reaction. A three component, one‐pot method is also achieved starting from terminal alkynes, tosyl azides, and dihydrofurans.magnified image

Organometallic nucleoside analogues with ferrocenyl linker groups: synthesis and cancer cell line studies.

Examples of organometallic compounds as nucleoside analogues are rare within the field of medicinal bioorganometallic chemistry. We report on the synthesis and properties of two chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group. These so-called ferronucleosides show promising anticancer activity, with cytostatic studies on five different cancer cell lines indicating that both functional groups are required for optimal activity.

A study on the impact of different clay minerals on the dispersing force of conventional and modified vinyl ether based polycarboxylate superplasticizers

The impact of three different clay minerals (montmorillonite, kaolinite and muscovite) on the dispersing force of vinyl-ether based PCE superplasticizers was studied. At first, a conventional vinyl-ether PCE was synthesized from maleic anhydride (MA), mono methoxy poly(ethylene glycol) ester of MA and 4-hydroxy butyl vinyl ether (HBVE). Additionally, a PEG-free PCE was prepared by substituting MPEG with hydroxyalkyl groups in the ester. Next, the effect of three different clay minerals on the fluidity of cement paste admixed with both PCEs was investigated. It was found that the conventional PCE is negatively affected by the clays in the order: montmorillonite≫kaolinite>muscovite. Whereas, the PEG-free PCEs were only slightly affected. The study suggests that conventional PCEs containing PEG reasonably tolerate all types of clay minerals except montmorillonite. When montmorillonite is present as a contaminant, then use of a PEG-free PCE such as described here presents a viable mitigation strategy.