Cationic condensing agent

Aiming at demonstrating the potentialities of the hexameric capsule as a substrate selective nanoreactor, Scarso and coworkers extended the concept to a stoichiometric reaction. In particular, the steric hindrance due to the confined space within the cavity of the capsule was exploited in the substrate selective amide synthesis mediated by the cationic condensing agent 1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride [47]. Similarly to the encapsulation of other cationic species, the cationic condensing agent that in... 

TABLE 7.1 Catalytic Tests for the Competitive Coupling of Pairs of Amines with one Acid and Pairs of Acids with one Amine Mediated by the Carbodiimide Cationic Condensing Agent in the Presence or Absence of the Hexameric Capsule as Supramolecular Nanoreactor at 60°C, Time 18 h. + Presence Absence... 

Fig. 5.5 The oligopeptide synthesis at cationic micelles using the condensation agent CDI leads to the intermediate (I), which is in equilibrium with an IV-carboxyanhydride (II). A free primary or secondary amino acid reacts with (II) and forms an amide linkage as well as a carbamide terminus. ...

Under a variety of conditions, plasmid DNA undergoes a dramatic compaction in the presence of condensing agents such as multivalent cations and cationic polymers. Naked DNA coils, typically with a hydrodynamic size of hundreds of nanometers, after condensation it may become only tens of nanometer in size. Contrary to proteins which show a unique tertiary structure, DNA coils do not condense into unique compact structure. Cationic polymers execute their gene carrier function by their condensation effect on gene materials and, furthermore, their protection effect on DNA from nuclease digestion. Currently, the most widely used cationic polymers in research include linear or branched PEI (poly (ethyleneimine) (161-165), polypeptides such as PLL (poly-L-lysine) (166-169), PLA (poly-L-arginine) (170). 

High concentration, however, is not the only means to obtain LC phases of DNA in aqueous solutions. DNA has been found to collapse upon adding in the solutions various condensing agents, which introduce effective attractive interhelical interactions. This is what happens with alcohols and other solvents, which reduce DNA solubility [40], or with multivalent cations like spermidine, spermine, and cobalt hexamine, which are thought to establish correlated counterion fluctuations with... 

Addition of polyelectrolyte DNA-condensing agents such as polyethyleneimine, polylysine, protamine sulfate, etc., before the addition of cationic lipids has become a widely accepted practice in an effort to stabilize and optimize lipoplexes performance... 

In conclusion, we have designed a synthetic vesicular DNA carrier that physically and functionally mimics an enveloped virus particle. To achieve an acceptable degree of encapsulation within the vesicle, we use a process that is essentially inverse to the preparation of cationic lipid-DNA complexes. A suitable DNA condensing agent is introduced that, at a certain critical concentration, conveys a weak net cationic charge to the condensed DNA that then interacts spontaneously with a liposome containing one or more anionic components. These DNA formulations behave distinctly different from classic cationic liposome DNA complexes in vitro in as much as they have been shown to be nontoxic, to display a traditional linear dose response, and to be serum-insensitive. 

A single-bath method can be used if desired. The dyes are dissolved separately and added to the dyebath which already contains an ethylene oxide condensate which acts as an anti-precipitant. The dyebath is adjusted to pH 5 to 5-5 with acetic acid and sodium acetate and the goods are entered at 40 to 45°C (104 to 113°F). A period of 45 minutes is taken to raise the temperature to the boil, at which it is maintained for one hour. Alternatively, the acrylic fibre may be dyed first and then the same liquor is neutralized and the cellulosic fibre is dyed. Application of a cationic fixing agent improves wet fastness of direct dyes but copper after-treatment should be avoided because this can have an adverse effect on the light fastness of the cationic dye. Very good fastness is obtained if, after the acrylic component has been dyed, the cellulosic fibre is brought to shade with vat dyes. 

Intrasoft . [Crompton Knowles] Fatty acid condensate cationic softening agent for textiles. 

Overall, the hexameric resorcin[4]arene capsule showed very interesting selective properties for the condensation reaction between carboxylic acids and amines mediated by a cationic carbodiimide-based condensing agent similarly to what was observed in the previous case for the alkyne hydration reaction, the capsule prefers the encapsulation of smaller and more compact substrates that react faster than longer ones. 

The discrete phase transition is induced by various kinds of condensation agents such as neural synthetic polymer (PEG) [6, 7], cationic surfactant (CTAB) [8, 9], alcohol [11], multi-valent inorganic cation [12], and polyamine [10]. 

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