With ether groups

The phase behavior of several polybibenzoates with oxyalkylene spacers has been reported [11,14,15,20-27]. These spacers include the dimer of trimethylene glycol and different ethylene oxide oligomers. The most noticeable characteristic of these polybibenzoates with ether groups in the spacer is the considerable decrease of the rate of the mesophase-crystal transformation. Thus, Fig. 8 shows the DSC curves corresponding to a sample of poly[oxybis(trimethylene)p,p -bibenzoate], PDTMB, with a structure similar to that of P7MB but with the... 

E. Mixed Complexes between Lithioacetonitrile and Chiral Lithium Amides with Ether Groups... 

The monomers used to generate polyesters can be used to form many copolymers that will contain ester groups. The esters can be included in copolymers with other esters, with ether groups, amides, carbonates, etc. Some examples of such copolymers are listed in Table 10.1.9. 

Stereoselective conversions of various terminal or phenyl-substituted internal alkynes with ether groups attached to the side chain using Ni[P(OPh)3]4 as a precatalvst give 1 89 mixtures of the regioisomers25. Hydrocyanation of aliphatic internal alkynol derivatives leads to 1 1 mixtures of both regioisomers25. 

Derivatives of d- and L-thrcitol with ether groups in positions 1 and 4, such as 33 and 34, have been used for the synthesis of chiral alkenes (Section D.l. 6.1.5.) and for the formation of monoke-tals with dicarbonyl compounds which then add Grignard reagents enantioselectively (Section D.l.3.1.4.). Both enantiomers of 1,4-di-O-benzylthreitol 33 and 1,4-di-O-methylthreitol 34 are commercially available and can be prepared from tartaric acid via the intermediate 4,5-bis(hy-droxymethyl)-2,2-dimethyl-1,3-dioxolanes (vide supra), either via butanediepoxide23,45 or directly by alkylation/hydrolysis23 46. 

The data presented in this review testify to the appearance of a large series of novel bis(naphthalic anhydrides). These monomers are characterized by structural moieties which determine an enhanced solubility (and processability) of the derived polyheteroarylenes. Bis(naphthalic anhydrides) with ether groups may be employed in the preparation of systems similar to polyetheramides but having higher glass transition temperatures. The majority of novel bis(naphthalic anhydrides) may be used in the preparation of novel poly-naphthoylenebenzimidazoles which combine satisfactory processability with very high thermal and chemical stability. 

During the polymerization, most of the cheap maleic anhydride residues isomerize to the technologically more desirable fumaric acid residues. In addition, up to 15% of the maleic acid double bonds add on glycol with ether group formation, and, so, the polycondensation cannot be carried out stoichiometrically. 

Cellulose ethers are obtained by the substitution of hydroxyl groups with ether groups. Different derivatives are commercially available, but the most important among the water soluble products are the CMC. These compounds, depending on the substituent density (or the degree of substitution, DS, characterizing the average number of... 

Functionalization of pyrrole with ether groups has been studied less, probably because of the difficulties often encountered in the synthesis of substituted pyrroles. 3,4-Dimethoxypyrrole (46) has been prepared [249] electropolymerization has given a highly conducting polymer (120 S cm" ), but its electrochemical behavior is not significantly different from that of polypyrrole. 

Calixarenes fully functionalized at the lower rim with ether groups show a weak affinity for alkali metal ions. The case of the tetramethyl ether of /7-T rT-butylcalix[4]arene (13) is quite interesting, since it is conformationally mobile, and can adapt its conformation to different metal ions. The Na+ ion is exclusively complexed by the cone isomer, while Cs is preferentially bound by the partial cone isomer. 

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