Hydrophobic amides

Interactions between proteins and salts in the binding buffer are also a major determinant of selectivity. Salts that are strong retention promoters in HIC are excluded from protein surfaces by repulsion from their hydrophobic amide backbones and hydrophobic amino acid residues.8,9 This causes the mobile phase to exert an exclusionary pressure that favors the association of proteins with the column, regardless of stationary-phase hydrophobicity.1(W2 Because this mechanism involves the entire protein surface, the degree of exclusion is proportional to average protein hydrophobicity, regardless of the distribution of hydrophobic sites. 

Rhone-Poulenc indicates that cellulose acetate with a degree of substitution of about 2 is biodegradable, in agreement with its earlier reference [176]. Cellulose has been discussed as a renewable resource [177], A recent publication [178] on chitosan reacted with citric acid indicates that the ampholytic product is biodegradable. Chitosan acetate liquid crystals [179], hydrophobic amide derivatives [180], and crossUnked chitosan [181] are also claimed to be biodegradable. 

Zhu Y-L, Kozuma Y, Katayama Y, Miura T (2009) Electrochemical behavior of Ni(II)/Ni in a hydrophobic amide-type room-temperature ionic liquid. Electrochim Acta 54 7502-7506... 

Very unstable modifications, like the reddish, chlorine-free a-copper phthalocyanine, can be stabilized with amides or salts of copper phthalocyanine sulfonic acids (59—63). Mixture with other metal phthalocyanines, eg, tin, vanadium, aluminum, or magnesium, also inhibits crystallization change and poor performance in binders and prints (flocculation) due to the hydrophobic character of unsubstituted phthalocyanines. 

Amines with Amide Linka.ges, Representatives of this group are prepared from carboxyUc acids and di- and polyamines. The amide linkage connects the amine to relatively inexpensive hydrophobes. Eormulas for typical amide amines are as foUow ... 

A variety of waxy hydrophobic hydrocarbon-based soHd phases are used including fatty acid amides and sulfonamides, hydrocarbon waxes such as montan wax [8002-53-7], and soHd fatty acids and esters. The amides are particularly important commercially. One example is the use of ethylenediamine distearamide [110-30-5] as a component of latex paint and paper pulp blackHquor defoamer (11). Hydrocarbon-based polymers are also used as the soHd components of antifoaming compositions (5) examples include polyethylene [9002-88-4], poly(vinyl chloride) [9002-86-2], and polymeric ion-exchange resins. 

Fluorocarbon soHds are rare in defoamer compositions, presumably on account of their cost. SoHd fluorine-containing fatty alcohols and amides are known. The most familiar fluorocarbon soHd is polytetrafluoroethylene [9002-84-0]. Because it is more hydrophobic than siHcone-treated siHca, it might be expected to perform impressively as a defoamer component (14). However, in conventional hydrocarbon oil formulations it works poorly because the particles aggregate strongly together. In lower surface tension fluids such as siHcone and fluorocarbon oils, the powdered polytetrafluoroethylene particles are much better dispersed and the formulation performs weU as a defoamer. 

A selection of amino acids (acid A, acid B,...) terminated at both ends by amide functionality, i.e., MeNHCO-CHR-NHCOMe, are provided. These are given in the ionization states found at neutral pH. For each, first identify the amino acid, and then the ionization state (neutral, protonated or deprotonated). Next compare electrostatic potential maps among the different amino acids. Which amino acids would prefer hydrophobic environments Hydrophilic environments Explain your reasoning. 

The C-6 carboxamide analogues of zanamivir, represented by the general structure 24, provided an avenue to introduce more hydrophobic side-chains onto the dihydropyran scaffold to interact with the hydrophobic regions of subsites S4 and S5 (reviewed in Islam and von Itzstein 2007). The most active tertiary amides (24 = alkyl) showed comparable inhibitory activity to their glycerol side-... 

As such, the magainins provide a useful initial target for peptoid-based peptido-mimetic efforts. Since the helical structure and sequence patterning of these peptides seem primarily responsible for their antibacterial activity and specificity, it is conceivable that an appropriately designed, non-peptide helix should be capable of these same activities. As previously described (Section 1.6.2), peptoids have been shown to form remarkably stable hehces, with physical characterishcs similar to those of peptide polyprohne type-I hehces (e.g. cis-amide bonds, three residues per helical turn, and 6A pitch). A faciaUy amphipathic peptoid helix design, based on the magainin structural motif, would therefore incorporate cationic residues, hydrophobic aromatic residues, and hydrophobic aliphathic residues with threefold sequence periodicity. 

The indicator variable I is assigned the value of 1 for the presence of amide derivatives and 0 for the esters. Its negative coefficient suggests that esters would be preferred over amides for this data set. nx is the calculated hydrophobic parameter of the X-substituents. Its positive coefficient suggests that the highly hydrophobic X-substituents would be preferred. 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

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