Diphenyl-2,2 -dicarboxylic acid

Diphenyl-2,2 -dicarboxylic acid, 35 Diphenyldi( 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propoxy)sulfurane, 239 Diphenyl diselenide, 235 Diphenyl disulfide, 31, 235-236, 313... 

Diphenic acid (diphenyl-2,2 -dicarboxylic acid) [482-05-3] M 242.2, m 228-229°, pK25 3.46. Crystallise dipherric acid from water. Hot AC2O provides the anhydride below. [Beilstein 9 H 922, 9 IV 3552.]... 

Dinitrodiphenic Acid (4 i -Dinitro-diphenyl-2 2 -dicarboxylic acid)... 

We expected that polyarylates derived from 4,4 -diphenyl-dicarboxylic acid(BB) would show increased stability of the liquid crystalline state compared with PEC due to the longer mesogen unit,but at the same time,we were afraid that melting temperatures(Tms) of these polyarylates would be very high because Tm of poly(ethylene 4,4 -diphenyldicarboxylate) was much higher than that of poly(ethylene terephthalate) and poly(methylhydroquinone terephtalate)(Me-HQ/TA) showed no liquid liquid crystallinity even at the temprature above 450 C. 

Aziridine, 2,3-diphenyl-l-(2,4,6-trinitrophenyl)-irradiation, 7, 61 Aziridine, 1,2-divinyl-rearrangement, 7, 539 Aziridine, 2,3-divinyl-rearrangement, 7, 42, 65, 539 Aziridine, N-ethyl-inversion, 7, 6 Aziridine, 2-halo-reactions, 7, 74 Aziridine, A/-halo-invertomers, 7, 6 Aziridine, 2-methyl- N NMR, 7, 11 Aziridine, methylene-ring-ring valence isomerizations, 7, 22 synthesis, 7, 92 Aziridine, iV-nitroso-reactions, 7, 74 Aziridine, iV-phosphino-inversion, 7, 7 Aziridine, 1-phthalimido-UV irradiation, 7, 62-63 Aziridine, l-(3-thienyl)-2-vinyl-rearrangement, 4, 746 Aziridine, 7V-trimethylsilyl-inversion, 7, 7 Aziridine, 1,2,3-triphenyl-irradiation, 7, 61 Aziridine, vinyl-isomerization, S, 287 Aziridinecarboxylic acid ring expansion, 7, 262 Aziridine-2,2-dicarboxylic acid, 1-methoxy-diethyl ester... 

Imidazole-4,5-dicarboxylic acids, coupling, 5, 403 decarboxylation, 5, 434 1-substituted synthesis, 5, 468 synthesis, 5, 362, 402, 484 Imidazole-4,5-dione, l-alkyl-2-phenyl-synthesis, 5, 129, 479 Imidazole-2,4-diones tautomerism, 5, 370 Imidazole-4,5-diones tautomerism, 5, 370 Imidazole-2,4-dithione, 5,5-diphenyl-tautomerism, 5, 370 Imidazole-2,4-dithiones tautomerism, 5, 370 Imidazolepropanol synthesis, 5, 486 Imidazoles accelerators epoxy resins, 1, 407... 

Thiophene-2,4-dicarboxylic acid, 3,4-diphenyl-diethyl ester, 4, 135... 

As the mechanism, a radical and a cationic pathway are conceivable (Eq. 31). The stereochemical results with rac- or mcjo-1,2-diphenyl succinic acid, both yield only trans-stilbene [321], and the formation of a tricyclic lactone 51 in the decarboxylation of norbornene dicarboxylic acid 50 (Eq. 32) [309] support a cation (path b, Eq. 31) rather than a biradical as intermediate (path a). 

Several routes have been reported for the synthesis of aromatic poly(azole)s such as poly(benzimidazole), poly(benzoaxazole), and poly(benzthiazole) melt polycondensation of dicarboxylic acid diphenyl esters with tetramines21 and high-temperature solution polycondensation of dicarboxylic acids or their derivatives with tetramine hydrochlorides in PPA.22 PPA acts as condensing agent and solvent. Ueda etal.23 developed a modified method for the synthesis ofpolyazoles with the use of PPM A. 

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). 

The technical production of poly(benzimidazole) (PBI) is also carried out in two steps. In the first step an aromatic tetramine is condensed with the diphenyl ester of an aromatic dicarboxylic acid at 220-260 °C, yielding a poly(amino amid) with elimination of phenol. Ring closure with elimination of water occurs in the second step (solid-phase polycyclocondensation), conducted at 400 °C and yielding the polybenzimidazole (experimental procedure, see Table 2.3). 

Various organic plasticizers having boiling points over 300 °C are available, such as di(2-ethylhexyl) phthalate (4a), di(2-ethylhexyl) adipate (8), oligomers formed from dicarboxylic acids and diols with molecular weights ranging up to 3500, esters of tri-mellitic acid, epoxidised fatty acids or organic phosphates, such as tris(2-ethylhexyl) phosphate (9) or (2-ethylhexyl) diphenyl phosphate (10). Most phosphates also function as flame retardants and some, such as 10, are smoke suppressants as well (Meier, 1990). 

Another group of polymeric organic tellurium compounds was obtained from diphenyl tellurium dichloride and disilver salts of dicarboxylic acids. 

When refluxed in acetonitrile or 1,4-dioxane, diphenyl tellurium dichloride and silver salts of dicarboxylic acids produced polymeric diphenyl tellurium carboxylates4. 

Decarboxylation of pyridazinecarboxylic acids usually presents no difficulty and it has been carried out by heating the acid alone or in sulfuric acid, generally over 200°. Decarboxylation of 4,5-pyrida-ziriedicarboxylic acid has been discussed earlier (Section II). Removal of both carboxyl groups has been performed with 3,6-diphenyl-4,5-pyridazinedicarboxylic acid and 4-oxo-l,4-dihydro-3,6-pyridazine-dicarboxylic acid, but more frequently stepwise decarboxylation is reported. The 4-carboxyl group is usually split off first from a 4,5-pyridazinedicarboxylic acid or 6-oxo-l,6-dihydro-3,4-pyrida-zinedicarboxylic acid, but not in the case of a 3,4-pyridazine-dicarboxylio acid where the 3-carboxyl is removed. ... 

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... 

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