Hydroxymethyl Functional Groups Research Articles

Investigation of the microscopic damage mechanisms in cotton fibers induced by mechanical friction

For the problem of friction damage in cotton fiber processing, a multi-scale combination of investigation methods is proposed. The surface of damaged cotton fiber is detected by relevant test means with damage features such as dislocations, defects and cracks. The internal pyranose ring and glycosidic bond fail, the crystallinity decreases, and the number of hydrogen bonds decreases. Anisotropy exists in the frictional properties of the microscopic surface of the cotton fiber. The results of molecular dynamics simulation showed that the cellulose main chain failed mainly at the glycosidic bond, and the side chain failed mainly at the hydroxymethyl functional group. Its interchain hydrogen bond O3H…O5 was the least damaged. The cellulose crystal (200) surfaces had poor abrasion resistance, and the frictional properties of each crystal surface were anisotropic. The results of the study provide a theoretical basis for improving friction and wear problems in cotton fiber processing.

Concise Synthesis of 2,5-Diketopiperazines via Catalytic Hydroxy-Directed Peptide Bond Formations.

2,5-Diketopiperazines (DKPs) with hydroxymethyl functional groups are essential structures found in many bioactive molecules and functional materials. We have established a simple protocol for the concise synthesis of this type of DKPs through diboronic acid anhydride-catalyzed hydroxy-directed peptide bond formations. The sequential reactions in this report, which consist of three steps, an intermolecular catalytic condensation reaction in which water is the only byproduct, a simple deprotection of the nitrogen-protecting group, and an intramolecular cyclization, enabled the synthesis of functionalized DKPs in high to excellent yields without any intermediate purification. The utility of this protocol has been demonstrated by synthesizing natural products, phomamide and Cyclo(Deala-l-Leu).

Greener approach for the synthesis of nitrovinylfurans from biomass-derived 5-hydroxymethyfurfural as selective antiproliferative agents

Biomass-derived chemical platforms such as 5-hydroxymethylfurfural (5-HMF) can offer straightforward access to new value-added products. The presence of an aldehyde and hydroxymethyl functional groups in this molecule are interesting structural motifs to explore the synthesis of new bioactive compounds. In this contribution, a strategy to quickly and efficiently synthesize nitrovinylfurans starting from 5-HMF under greener conditions is described and the antiproliferative activity of the synthesized compounds evaluated. 5-HMF obtained by microwave-assisted saturated biphasic dehydration from fructose was used to produce furaldehyde derivatives. Next, through a nitroaldolic condensation, the desired nitrovinylfurans were generated using efficient heating sources, ultrasound, or a non-microwave instant heating reactor, under solvent-free conditions. Most of the newly synthesized compounds showed growth inhibition when assayed for their in vitro antiproliferative activity against six cancer cell lines (A549, HBL-100, HeLa, SW1573, T-47D, and WiDr), with lower toxicity on the human macrophage-like cells (THP-1). Our strategy allowed the rapid identification of nitrovinylfurans 16, 17, 19, and 20 as future candidates for the development of new selective anticancer drugs.

Liquid-Phase Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over Co/Mn/Br Catalyst

2,5-Furandicarboxylic acid (FDCA), mainly synthesized by the selective oxidation of 5-hydroxymethylfurfural (HMF), is a biobased monomer for high-performance polymers. In this work, we have a comprehensive investigation on the rapid and highly selective oxidation process of HMF to FDCA in acetic acid (HAc) with Co/Mn/Br catalyst and air as the oxidant. It was found that both aldehyde and hydroxymethyl functional groups of HMF could be first oxidized in the sequential oxidation of HMF to FDCA, but 2,5-diformylfuran (DFF) was the main oxidation intermediate. Apart from the side reaction of HMF overoxidation to COx (CO and CO2) and HMF condensation to polymers, a small part of HMF will be further oxidized to maleic acid (MA) and fumaric acid (FA) via the ring-opening reactions under severe conditions because of the instability of furan ring. To reduce the side reactions and maximize the FDCA yield, the effects of temperature, pressure, substrate solvent ratio, catalyst composition and concentration, and water concentration on the main reactions and side reactions of the HMF oxidation were systematically evaluated. Under the optimum conditions, the selectivity of FDCA reached 92% with the total conversion of HMF in less than 20 min at a high mass ratio of substrate and solvent (1/9), and the purity of FDCA exceeded 99.8%. The experimental results provide a great reference and inspiration for the optimization of the HMF oxidation process and the large-scale production of FDCA.

Improved synthesis of MC4-PPEA and the biological evaluation of its hydroxymethyl derivative

Nicotinamide phosphoribosyltransferase (Nampt) is an intriguing target for the treatment of many diseases, including cancer. Previously, our group demonstrated that carborane clusters may be used to increase the potency of small molecule inhibitors of Nampt over other, similarly sized organic moieties. Herein, we report a greatly improved, gram-scale synthesis of our most potent agent: 1-(4'-(trans-3″-(3‴-pyridyl) acrylamide)butyl)-1,7-dicarba-closo-dodecaborane (MC4-PPEA). Additionally, the carborane moiety of the molecule has been modified with a hydroxymethyl functional group to allow for its covalent attachment to targeted prodrugs, the synthesis of which are underway. Using cell viability assays, we demonstrate that this new derivative exhibits low, to mid-nanomolar potencies against human breast cancer cell lines in vitro.

Synthesis and Reactivity of Tris(Hydroxymethyl)Phosphine-Mimicking Nonsymmetrical Diphosphine Ligands

GRAPHICAL ABSTRACT

Hydroxylated Detonation Nanodiamond: FTIR, XPS, and NMR Studies

Detailed and unambiguous characterization of the surface structure of detonation nanodiamond (DND) particles remains one of the most challenging tasks for the preparation of chemically functionalized nanodiamonds. In the present paper, a combination of FTIR, NMR, and XPS was used to characterize DND particles that were treated in a reduction reaction that results in the enrichment of hydroxyl and hydroxymethyl functional groups. FTIR spectra and quantum-chemistry modeling demonstrated that the vacuum treatment of the sample, with the purpose of the removing adsorbed water and other volatile contaminates, is mandatory to obtain the correct data on the nature and relative content of the −OH surface groups on DND. 13C and 1H NMR spectra show signals from the diamond core, hydroxyl, hydrocarbon groups, and moisture on the diamond surface. NMR data were taken for as-prepared DNDs, as well as those that were dried under vacuum conditions of 10–4 Torr, in order to distinguish between the NMR signal contributions...

Thymine‐functionalized polystyrenes for applications in biotechnology. III. Increasing the thymine loading via a new synthetic pathway

AbstractIn this article, we report an efficient method for the synthesis of thymine‐functionalized polystyrene microspheres. First, poly(styrene‐co‐4‐chloromethylstyrene) copolymers slightly crosslinked with divinylbenzene were synthesized in batch free‐radical emulsion copolymerization. Microspheres with a particle size of ∼40–70 nm were obtained with greater than 99% conversion. The chloromethylstyrene (CMS) groups were then converted into thymylmethylstyrene (TMS) in a two‐phase system with greater than 80% efficiency, and up to a 45 mol % thymine loading was achieved. The functionalized microspheres were characterized by elemental analysis, Fourier transform infrared, and X‐ray photoelectron spectroscopy. The analyses revealed partial hydrolysis of the CMS functionalities, yielding hydroxymethyl functional groups in addition to the thymine functionalities. These copolymers have potential applications in biotechnology. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5545–5553, 2005

Syntheses of four peptides from the immunodominant region of hepatitis C viral pathogens using PS-TTEGDA support for the investigation of HCV infection in human blood.

Four peptides were designed and synthesized on a highly solvating copolymer of tetraethyleneglycol diacrylate cross-linked polystyrene (PS-TTEGDA) support with very high purity and yield. The polymer was synthesized in various cross-linking densities (1, 2, 3, 4, 5 and 10%) using radical aqueous suspension polymerization. Four per cent PS-TTEGDA resin showed rigidity and mechanical characteristics comparable with those of divinylbenzene cross-linked polystyrene (PS-DVB) support. Swelling and solvation characteristics of PS-TTEGDA were much higher than PS-DVB support in all solvents used in solid-phase peptide synthesis. Forty-eight hour treatment of the support with neat trifluoroacetic acid did not show any change in its infrared spectra. PS-TTEGDA could be functionalized with chloromethyl, aminomethyl and hydroxymethyl functional groups under various controlled conditions. Synthetic utility of the support was demonstrated by the synthesis of four peptides selected from the envelope and nonstructural protein region of the prototype hepatitis C virus (HCV). These peptides were later used successfully to develop a peptide-based immunoassay (PBEIA) for the detection of HCV immunity. Peptides designed from the NS1 and NS4 protein regions were found to be very promising for the development of a new diagnostic kit to detect HCV infection in human blood. Peptide purity was tested by RP-FPLC and the peptide identity was confirmed by amino acid analysis.

Examination of selected synthesis parameters for typical wood adhesive‐type urea–formaldehyde resins by 13C NMR spectroscopy. I

Selected synthesis parameters of typical wood adhesive-type urea–formaldehyde (UF) resins were examined using the 13C NMR spectroscopy. The monomeric hydroxymethylureas and methylene–ether derivatives formed in the initial alkaline reaction polymerize in the subsequent acidic reaction by forming methylene bonds and cleaving some hydroxymethyl groups as formaldehyde. For typical resin syntheses at F/U ratio of 2.10, the resulting UF polymer is found to be a number-averaged pentamer having 3.25 polymer chain branches with about 80% of chain ends bonded to hydroxymethyl groups and the rest being free amide groups. When the second urea is added during the cooling period, about 67% of hydroxymethyl groups cleave from the UF polymeric components and the freed formaldehyde reacts with second urea to form monomeric hydroxymethylureas. This hydroxymethyl group move is suppressed when the second urea is added at low temperatures, suggesting that wood adhesive-type UF resins are composed of monomeric and polymeric UF components having hydroxymethyl functional groups in varying proportions. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 995–1007, 1999

Examination of selected synthesis parameters for typical wood adhesive-type urea-formaldehyde resins by13C NMR spectroscopy. I

Selected synthesis parameters of typical wood adhesive-type urea–formaldehyde (UF) resins were examined using the 13C NMR spectroscopy. The monomeric hydroxymethylureas and methylene–ether derivatives formed in the initial alkaline reaction polymerize in the subsequent acidic reaction by forming methylene bonds and cleaving some hydroxymethyl groups as formaldehyde. For typical resin syntheses at F/U ratio of 2.10, the resulting UF polymer is found to be a number-averaged pentamer having 3.25 polymer chain branches with about 80% of chain ends bonded to hydroxymethyl groups and the rest being free amide groups. When the second urea is added during the cooling period, about 67% of hydroxymethyl groups cleave from the UF polymeric components and the freed formaldehyde reacts with second urea to form monomeric hydroxymethylureas. This hydroxymethyl group move is suppressed when the second urea is added at low temperatures, suggesting that wood adhesive-type UF resins are composed of monomeric and polymeric UF components having hydroxymethyl functional groups in varying proportions. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 995–1007, 1999

Reverse Phase High Performance Liquid Chromatography of Human Bence Jones Proteins

Abstract A high performance liquid chromatography system is presented for analytical and preparative separations of human Bence Jones proteins. The method utilizes 5–7 um macroreticular polystylene resin with bonded hydroxymethyl functional groups, and the proteins are eluted with a linear gradient of an increasing concentration of acetonitorile(10–60%, V/V) in 0.1 % (V/V) trifluoroacetic acid, pH 2.1. By this elution condition, seven X type Bence Jones proteins with molecular weights of 23,600 (monomer)-47,000(dimers) daltons(216–434 amino acids) were eluted within 80 min with the yields of 78%–98%. The method allows a rapid and sharp elution of Bence Jones proteins.

Stepwise reduction of coordinated carbon monoxide

Reduction of ((eta-C/sub 5/H/sub 5/)Re(NO)(CO)/sub 2/)(BF/sub 4/) (1) by NaBH/sub 4/ in THF and THF/H/sub 2/O mixtures afforded formyl ((eta-C/sub 5/H/sub 5/)Re(NO)(CO)CHO, 2), hydroxymethyl ((eta-C/sub 5/H/sub 5/)Re(NO)(CO)CH/sub 2/OH, 3), and methyl ((eta-C/sub 5/H/sub 5/)Re(NO)(CO)CH/sub 3/, 4) derivatives selectively and in high yields depending upon stoichiometry and reaction conditions. Individual reduction steps among 1 to 4 have been investigated. Reduction of 2 to 4 and 3 to 4 by NaBH/sub 4/ in THF demonstrates the activation of formyl and hydroxymethyl functional groups in these complexes. Pentamethylcyclopentadienyl analogues of all compounds have been prepared; (eta-C/sub 5/Me/sub 5/)Re(NO)(CO)CHO (6) has enhanced stability and crystallinity relative to 2 and can be isolated in analytically pure form. 1 figure.