By ester groups

In 2004, Weberskirch and co-workers tried a new approach by synthesising [RhBr(COD)(NHC)] 23 (NHC = l-(2 -hydroxyethyl)-3-methylimidazolidine-2-ylidene) [28]. Subsequently, attaching the unsymmetrical, monohydroxy-functionalised NHC by ester groups to an amphiphilic, water-soluble polymer support (ps)... 

Dicyclopropylallene reacts with olefins activated by ester groups at 200 °C to yield the adducts 20 predominantly (Table 12.1). In contrast, the reactions with methylenemalononitrile occurred at room temperature with selective production of the adduct 19 [18], A dipolar mechanism is assumed for the latter reaction. 

Especial points which emerge from these studies include (a) the almost complete absence of reactivity of the hydroxy-groups of simple carbohydrates in water, which is attributed to their powerful solvation by water preventing a close approach of any other solute and (b) the ability of ester groups to interact with proton-acceptors. The refractive index tests, examination of m.p. or b.p., and infrared spectra of certain mono- and poly-esters appear to be interpreted most simply by assuming the formation of weak CH bonds by ester groups under the activating influence of the adjacent (5—0 double bond. These bonds can account for certain properties of l 2-diesters and for the adsorption of proton-acceptor solutes by cellulose acetates. 

Where the polymer-to-plasticizer attraction is strong, the plasticizer has high compatibility with the resin and is said to be of the primary or solvent type. With polyvinyl chlondc this attraction is furnished particularly well by ester groups. Where the polymer-to-plasticizer attraction is low the plasticizer is of the secondary or nonsolvent type it functions as a spacer between polymer chains but cannot be used alone because of limited compatibility. This is manifested by exudation of the plasticizer from the resin. Secondary plasticizers are often employed to take advantage of other desirable properties which they may impart Where they are used merely to cheapen the formulation, they are usually referred to as extenders. ... 

Lehmann et al. developed the concept of star-shaped molecules composed of three phenylbenzoate based rod-like cores directly connected by ester groups to a central... 

Activation of alkenes by amides and A-alkylamides has not been used as much as activation by ester groups. The amides are more difficult to reduce than the corresponding esters but have been reported to give the LHDs in 40-80% yields [2,4]. 

In LC polymers possessing mesogenic cores linked by ester groups, it is possible for transesterification to occur at elevated temperatures. In... 

Copolymers of ACN with other monomers containing fluorophores and attached to the polymer chain by ester groups had exciton migration distances which are greater than their calculated end-to-end distances, CTable IV). It is noted that ester groups may be photo-labile. 

Polyesters are step-growth polymers in which the monomer units are joined together by ester groups. They have found wide commercial use as fibers, plastics, and coatings. The most common polyester is known by the trade name Dacron and is made by the transesterification (Section 17.10) of dimethyl terephthalate with ethylene glycol. High resilience, durability, and moisture resistance are the properties of this polymer that contribute to its wash-and-wear characteristics. 

The new quats generation presents readily biodegradable surfactants the long chains of which are interrupted by ester groups, thus named "esterquats" [102, 108]. Esterquats are derived frequently from the diester of triethanolamines and the partially hydrogenated tallow or oleic acid followed by a diester quaternisation. The final product, N-methyl-N,N-di[2-(Ci6-i8-acyIoxy)-ethyl]-N-(2-hydroxyethyl)ammonium methosulphate (VIII), of the formula... 

OEt introduction of both new substituents directed by ester group... 

Lower solvatochromism in the polymer spectrum implies that merocyanine is solvated by ester groups of the same polymer chain and are shielded from the bulk solvent. This observation fits in with the foregoing conclusions on microenvironment polarity as estimated from the shift of the absorption band of the solvatochromic reporter SB. 

Vinyl ester resin n. Any of several epoxy-related resins in which the epoxides groups have been replaced by ester groups, typically acrylic. When cured, they have excellent resistance to strong chemicals such as chlorine and caustics. 

Poly(e-caprolactone) (PCL) consists of sequences of methylene units separated by ester groups and is one member of the general series of aliphatic polyesters 2 which have different methylene to carbonyl ratios, i.e. have different values of n. In these structures there is little steric hindrance to rotation about main-chain bonds and, in consequence, amorphous PCL has a low glass-transition temperature and is soft and rubbery. Regularity in its molecular structure renders PCL highly crystallisable and the crystalline entities reinforce the material and enhance its mechanical properties. 

As a result, it clarified that fatty acid ester was a great influential factor on the processability of NR. The relationship between non-rubber part content and the occurring gel content at the different storage intervals of 3 and 6 months showed that the protein and fatty acid ester present on the rubber molecules closely related to the occurring gel content as shown in Table 18.2. The processability might be assumed to closely relate to the gel content that was mainly caused by ester groups present on the NR molecules. 

Polyesters A substance with two alcohol groups reacts with a substance with two carboxylic acid groups to form a polyester, a polymer whose repeating units are joined by ester groups. The reactant molecules join as links of a chain to form a very long... 

Depsides, tridepsides, and tetradepsides consist of two, three, and four hydroxybenzoic acid residues linked by ester groups. These are the most numerous classes of secondary metabolites in lichens. More than one hundred Uchen compounds are depsidones, which have an additional ether bond between aromatic rings. Depsidones in Uchen are believed to arise by oxidative cycUzation of depsides. It has been found that depsidone and depside compounds such as atranorin, divaricatic acid, lecanoric acid, evemic acid, salazinic acid, physodic acid, and stictic acid possess important antimicrobial activity (Manojlovic et al. 2012 Kosanic et al. 2013, 2014a Rankovic et al. 2014). 

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