Hydrophobic derivatives

The hydroxypropyl derivative of guar GaM (HPG) was prepared with propylene oxide in the presence of an alkaline catalyst. HPG was subsequently etherified as such with docosylglycidyl ether in isopropanol and presence of an alkaline catalyst [432]. The peculiar features of the long-chain hydrophobic derivatives were ascribed to a balance between inter- and intramolecular interactions, which is mainly governed by the local stress field. 

Organic modification of the nanofillers to obtain hydrophobic derivatives having improved compatibility with the polymer. 

A similar procedure was adopted for synthesis of nanoparticles of cellulose (CelNPs). The polysaccharide nanoparticles were derivatised under ambient conditions to obtain nanosized hydrophobic derivatives. The challenge here is to maintain the nanosize even after derivatisation due to which less vigorous conditions are preferred. A schematic synthesis of acetyl and isocyanate modified derivatives of starch nanoparticles (SNPs) is shown in scheme 3. The organic modification was confirmed from X-ray diffraction (XRD) pattern which revealed that A- style crystallinity of starch nanoparticles (SNPs) was destroyed and new peaks emerged on derivatisation. FT-IR spectra of acetylated derivatives however showed the presence of peak at 3400 cm- due to -OH stretching indicating that the substitution is not complete. 

In the ion-association extraction systems, hydrophobic and interfacially adsorbable ions are encountered very often. Complexes of Fe(II), Cu(II), and Zn(II) with 1,10-phenanthro-line (phen) and its hydrophobic derivatives exhibited remarkable interfacial adsorptivity, although the ligands themselves can hardly adsorb at the interface, except for protonated species [19-21]. Solvent extraction photometry of Fe(II) with phen is widely used for the determination of trace amounts of Fe(II). The extraction rate profiles of Fe(II) with phen and its dimethyl (DMP) and diphenyl (DPP) derivatives into chloroform are shown in Fig.9. In the presence of 0.1 M NaC104, the interfacial adsorption of phen complex is most remarkable. The adsorption of the extractable complex must be considered in the analysis of the extraction kinetic mechanism of these systems. The observed initial rate r° shows the relation... 

Although there are other types of nonionic surfactant, the great majority are adducts of ethylene oxide with hydrophobes derived from three sources ... 

It was found that in spite of the large excess of modifying amine (N-isopropyl-, -diethyl, -dipropyl, -diisopropyl, -n-hexyl, -cyclohexyl, -n-octyl), the extent of substitution did not exceed 5-10 molar %. For the case of the N-isopropyl derivative, i.e. [poly(AAm-co-NiPAAm)], the authors connected such results with the temperature-induced conformational transformation of partially hydrophobized copolymer acquiring the contracted conformation, "... which made it difficult for N-isopropylamine to react further with the amide groups [22], Unfortunately, no data on the solution behaviour of these interesting copolymers have been reported to date, although there is a high probability that they would demonstrate certain properties of the protein-like macromolecules. At least, in favour of similar supposition is supported by the results of our studies [23] of somewhat different PAAm partially hydrophobized derivative, whose preparation method is depicted in Scheme 3. 

A new class of lipophilic ferrichrome analogs carrying acetoxymethyl ester moieties 203 has been synthesized and shown to penetrate rapidly through cell membranes. Intracellular esterase mediated hydrolysis transformed the lipophilic termini from hydrophobic to hydrophilic. The intracellular retention was visualized in hepatoma cells by labeling these analogs with a fluorescent naphthy-imide probe . Their fluorescence analogs retained their fluorescent properties for extended periods in comparison to hydrophobic derivatives 204 lacking the cleavable substituents. 

M,N -Dialkyl, Af,AT-diaryl-dipicolinamides [261-263] 2,6-bis( 1 -Aryl-1 -H-tetrazol-5-yl)pyridines (ATP, [265]) Hydrophobic derivatives of N,N A AT-tetrakis (2-methylpyridyl ethylenediamine (TPEN [266])... 

Matsumura, T., Takeshita, K. 2006. Extraction behavior of Am(EH) from Eu(III) with hydrophobic derivatives of N,N,N ,N -tetrakis(2-methylpyridyl)ethylenediamine (TPEN). Journal of Nuclear Science and Technology 43(7) 824—827. 

Since most P-gp effectors are hydrophobic, it was of interest to study flavonoids substituted with different hydrophobic groups, for example the isoprenyl group [210]. Isoprenylated flavonoids are natural compounds which constitute a class of plant secondary metabolites. Comte et al. [210] have synthesized a series of C- or O-substituted hydrophobic derivatives of chrysin (22). Increasing the hydrophobicity of substituents at positions 6, 7, or 8 increased the affinity of binding to the purified cytosolic domain of P-gp. Isoprenylated derivatives also increased intracellular daunomycin (78) accumulation in K562/R7 leukemic cells. 

ISEs Based on Cobyrinates. Vitamin B12 is hydrophilic and, therefore, it is necessary to modify it chemically in order to use it as ionophore in polymer membrane-based ISEs. Different hydrophobic derivatives that lack the nucleotide part of the vitamin (cobyrinates) have been prepared for this purpose. These compounds, although structurally similar to vitamin B12, have a quite different coordination behavior from that of the vitamin (7). 

The conversion of hydrophilic analytes into more hydrophobic derivatives... 

Hydrophobic derivatives Alkylated (3-CyD DE-(3-CyD TE-(3-CyD Acylated (3-CyD TAcyl-(3-CyD TValeryl-(3-CyD... 

It is reported that the covalent attachment of PEG or other polymers to enzymes allows them to be soluble in polar organic solvents (e.g., dioxane, carbon tetrachloride, and benzene), which in turn enhances their catalytic rates. ° The methodology involves tedious bioconjugation chemistry steps to attach activated forms of polymers (e.g., PEG monomethyl ether) to the free amino (lysine) groups of enzymes. In addition, isolation of the modified protein from the bioconjugate chemical reaction mixtnre is required. Proteins can also be modified using fatty acid chlorides, to create hydrophobic derivatives for cell membrane insertion. Modification is not recommended by the author for most situations due to the modest... 

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