4,4 -Diphenyl ether dicarboxylic acid

Isophthaloyl chloride 4 4 -Diphenyl ether dicarboxylic acid 2,2 -(Oxydi-4,l-phenylene)bis[5-(4-fluorophenyl)-l,3,4-oxadiazole] 1... 

A perfect transformation of an a2 + b2b into an ab2 polycondensation was first reported by a team of DSM NV [78, 79], Bis(2hydroxypropyl)amine reacts rapidly and almost quantitatively with the amino group, so that a bis(hydroxyalkyl) carboxylic acid is formed (see Formula 10.5). The polyesterification at higher temperatures yields a poly(ester amide), which was commercialized under the trademark Hybrane. Another example of an in situ formation of an ab2 monomer was described by Shu et al. [80]. The reaction of 1,4-diaminobenzene with the monoanhydride of a diphenyl ether tetracarboxylic acid (see Formula 10.5) produces an amino dicarboxylic acid which upon further polycondensation yields a hb poly(amide imide). Polycondensations of 4,3, 5 -trifluorodiphenylsulfone with commercial diphenols were studied by the Fossum group [81, 82]. The para C-F bond id particular reactive and substitution of one meta-position lowers the reactivity of the last C-F group. Therefore, variation of the reactions conditions allows for systematic variation of the DB. 

The thermal ring closure of AM 1 -ethyl-4-oxo-1,4-dihydroquinolin-7-yl)aminomethylenemalonate (605) in diphenyl ether at 260°C for 1 hr afforded l,7-phenanthroline-3,9-dicarboxylic acid 9-ethyl ester (606) in 23% yield (88USP4719302). 

An investigation of several phenyl-substituted oxetanes and of rrani-diethyl oxetane-2,3-dicarboxylate has been carried out in hot solutions rather than in the gas phase. The solvents must, of course, be high boiling and completely free of any acidic impurities, which would cause an acid-catalyzed decomposition. 2,2-Diphenyl-3,3,4,4-tetramethyloxetane (27) pyrolyzed at 310 °C at practically the same rate in each of three solvents of quite different polarity — diphenyl ether, DMF and TMEDA — showing that the intermediate is relatively non-polar. High regioselectivity is shown in this reaction, which gave mainly benzophenone... 

Phenazine-1,6-dicarboxylic acid (1) is a precursor for microbiological transformation to phenazine-6-carboxylic acid. " - Decarboxylation of phenazine-l,6-dicarboxylic acid (1) in refluxing diphenyl ether affords a mixture of phenazine (2 yield 33%) and phenazine-l-car-boxylic acid (3 yield 25% mp 242-243... 

Table 22 lists four polymer series of PEIs which contain an ether, sulphone or carbonyl linked diphenyl tetracarboxylimide unit [36]. Each of the four series contains two imide and two ester groups and have four aromatic co-monomers. Polymer series 7 and 9 also contain two units of p-aminophenol in conjunction with a bicyclic aromatic dicarboxylic acid, whereas polymer series 6 and 8 are based on m-aminophenol. The Mesogenic Index correctly predicts that series 6, 8 and 9 give rise to isotropic copolymers. However, in the case of series 7, in which the variable monomer was based on ether or thioether diphenol derivatives, thermotropic phases were observed in all three cases. When all four series are viewed as a whole it is clear that an MI value of 9.5 represents a borderline condition for a mesophase to occur. It also corresponds with the minimum value for a mesophase observed in NCPT-based PEIs. 

Ethyl cyanoacetate added with cooling to benzalmethylamine in ether, and allowed to stand 24 hrs. at room temp. l,3-diphenyl-2,4-dicyanocyclobutane-2,4-dicarboxylic acid ethyl ester methylamide. Y 78%. F. e. s. H. Bohme and S. Ebel, B. 98, 1819 (1965). 

When the methine base derived from trilobamine diethyl ether ethiodide is oxidised by permanganate it furnishes 2-ethoxydiphenyl ether 5 4 -dicarboxylic acid, identical with that (XXXIV p. 348, R = Et) similarly formed from oxyacanthine (p. 347) or dauricine (p. 358) and in the present ease derived from the diphenyl ether residue represented by rings (1) and (2) in formula (A) or (B). This fixes the position of one hydroxyl group at OR in (A) or (B) the position of the second is still undetermined but it may well be OR in ring (3) of (A) or ring (4) of (B). ... 

Among melt-spun fibers, those based on thermotropic liquid-crystalline melts have the highest strength and rigidity reported to date, and appear comparable to polyamides spun from lyotropic liquid-crystalline solutions. This was a very active field of research in the 1970s and later, and many comonomers have been reported. Obviously, these compositions must contain three components at a minimum, but many have four or five components. Some frequently used constituents, in addition to those mentioned above, are 2,6-naphthalene-dicarboxylic acid, hydro-quinone, 4,4 -biphenol, isophthalic acid, and 4,4 -dihydroxy-diphenyl ether. 

---