Biphenyl-2,2 ,6,6 -tetracarboxylic acid

In connection with their synthetic approach to the study of axial pseudoasymmetry, Prelog and co-workers (81) systematically desymmetrized the D2d symmetry inherent in biphenyl-2,2, 6,6 -tetracarboxylic acid (Figure 15) by converting the four functional groups to proper AS units. In principle this is identical with the desymmetrization of spiro [4.4] nonane (Figure 8), which was shown to afford four symmetries D2, S4, C2, and Cj. The desymmetrization (81) was achieved by amidation with optically active a -phenylethylamine. It should be noted that the interesting compound (-)-64, m.p. 140°C of D2 symmetry, which was prepared simply by amidation with the (-)-(5)-amine, possesses no axial chirality. 

Figure 15. Schematic representation of the diastereomers generated by desymmetrization of biphenyl-2,2, 6,6 -tetracarboxylic acid with enantiomeric o-phenylethylamines.

Cheng L, Wang JQ, Gou SH. A new three-dimensional cobalt(II) coordination polymer based on biphenyl-2,2 6,6 -tetracarboxylic acid and 1,2,4-triazole synthesis, crystal structure and magnetic properties. Inorg Chem Commun 2011 14(1) 261. ... 

A noteworthy example of dynamic motion and rearrangements of the molecular components in response to guest removal in SC-SC manner is found for the 2D square-grid MOF, [Ni(cyclam)]2[BPTC] 2nH20 [36]. This compound on heating loses all the water molecules to yield [Ni(cyclam)]2[BPTC] [36 j (H4BPTC = 1,1 -biphenyl-2,2, 6,6 -tetracarboxylic acid). Cell parameters... 

Oxidative homocoupling of aromatic and heteroaromatic rings proceeds with Pd(OAc)2 in AcOH. Biphenyl (165) is prepared by the oxidative coupling of benzene [104,105], The reaction is accelerated by the addition of perchloric acid. Biphenyl-tetracarboxylic acid (169), used for polyimide synthesis, is produced from dimethyl phthalate (168) commercially [106], Intramolecular coupling of the indole rings 170 is useful for the synthesis of staurosporine aglycone 171 [107]. 

IR spectroscopy may be used to follow two reactions occurring in polyimides exposed to high temperatures and humidities hydrolysis of the imide linkages and hydrolysis of residual anhydride end groups. The hydrolytic susceptibilities of several polyimides were measured at 90°C/95% R.H. Polymers based on benzophenone tetracarboxylic acid dianhydride (with either oxydianiline or m-phenylene diamine) appeared to undergo rather rapid hydrolysis initially, but the reaction had essentially halted by the time the measured imide content had decreased by 5-6%. Polymers based on 3,3 ,4,4 -biphenyl tetracarboxylic acid dianhydride (with p-phenylene diamine) and pyromellitic dianhydride (with oxydianiline) showed no significant imide hydrolysis. In all the polymers, the anhydride was hydrolyzed quite readily. 

The polyamic acids were prepared in these laboratories using modifications of a standard preparation (7). Benzophenone tetracarboxylic acid dianhydride (BTDA), benzenetetracarboxylic acid dianhydride (pyromellitic dianhydride PMDA), oxydianiline (ODA), 1,4-phenylenediamine (PDA) and 1,3-phenylenediamine (MPDA) were all obtained from Aldrich Chemical Co. The S -biphenyl tetracarboxylic acid dianhydride (BPDA) was obtained from Ube Chemical Company. The polyamic acids were prepared in N-methylpyrrolidinone (BTDA-ODA, BTDA-MPDA and BTDA with a 1 1 molar ratio of MPDA and ODA) or dimethyl acetamide (BPDA-PDA and PMDA-ODA). 

Pyrido[2,l-/][l,2,4]triazine-5,6,7,8-tetracarboxylic acid, 4,4a-biphenyl-l-p-tolyl-synthesis, 3, 428 Pyridotropylium cations... 

The first patent of Edwards and Robinson147 claims the condensations of pyromel-litic acid and aliphatic diamine salt to prepare polyimide. Recently, that approach has been revisited, and biphenyl tetracarboxylic and pyromellitic acids give a salt monomer by reaction with 1 mol of an aliphatic diamine (octamethylene diamine and dodecamethylene diamine). The salts were polymerized under 250 MPa at 250°C for 5 h in closed reaction vessels (Fig. 5.32) giving crystalline polymers.148 By reaction of pyromellitic tetraacid with oxydianiline, it has been possible to isolate a monomeric salt. It was polymerized under 30 MPa giving a PMDA-ODA polyimide with water elimination. 

Dibenzothiophene acts as a 7r-electron donor and readily forms complexes with known electron acceptors. In such cases the electronic spectrum of a solution of the two compounds shows a new absorption band, usually in the visible region. The order of donor strengths of several o,o -bridged biphenyls has been estimated from their respective charge-transfer spectra and found to be carbazole > fluorene > dibenzothiophene >dibenzofuran. Dibenzothiophene forms complexes with tetracy-anoethylene, various polynitro derivatives of fluorenone, > naphthalene-1,4,5,8-tetracarboxylic acid dianhydride, and tetra-methylmic acid. ... 

Starting materials and solvents were purchased from Aldrich Chemical Co. acetonitrile (ACN), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP) were obtained anhydrous in Sure/Seal bottles and used as received. The polyamic acid of PMDA-ODA (2545 Pyralin) was supplied by DuPont. The soluble polyimide XU-218, derived from 3,3, 4,4 -benzophenone tetracarboxylic dianhydride (BTDA) and diamino-1,1,3-trimethyl-3-phenylindan isomers (DAPI) was purchased from Ciba-Geigy Corp. The acetylene terminated imide oligomer powder (Thermid MC-600) derived from BTDA, aminophenylacetylene, and 1,3-bis (2-aminophenoxy) benzene (APB) was obtained from National Starch and Chemical Company. Kapton Type II (PMDA-ODA) films were obtained from DuPont Co., Apical polyimide films were obtained from Allied Corp., and Upilex Type-S and Type-R polyimide films derived from 3,3, 4,4 -biphenyl tetracarboxylic dianhydride (BPDA) plus p-phenylenediamine (PDA) and ODA, respectively were obtained from ICI Americas Inc. 

Other popular scaffolds have been derivatives of biphenyls which are now readily prepared using solid phase methods [265,464-469]. A solution phase approach has been to react a polyfunctional ised core containing reactive groupings - acid chlorides or isocyanates are easily prepared examples -with a mixture of reagents. One of the earliest synthetic examples showed the use of cubane tetracarboxylic acid chloride [151]. Two recent methods have used functionalised xanthene (library 71) [470] or diphenylmethane cores (library 72) [471] to identify DNA and urokinase receptor antagonists respectively. 

All PEIs derived from 3-aminophenol exclusively formed only isotropic melts. Thermotropic character was however observed in PEIs derived from 4-aminophenol and diphenylether 3,3, 4,4 -tetracarboxylic acid, but not when diphenyl sulphone or isopropylidene diphenyl units were employed. PEIs formed from 4-aminophenol and biphenyl-3,3, 4,4 -tetracarboxylic anhydride have also been found to form nematic melts [37]. 

C22H14N206 polyamidocarboxylic acid based on 3,3, 4,4 -biphenyl-tetracarboxylic dianhydride and para-phenylene diamine 182... 

Application of this technique to the identification of methyl esters of the organic acids obtained by the controlled oxidation of bituminous coal allowed the more volatile benzene carboxylic acid esters to be identified (Studier et al., 1978). These were esters of benzene tetracarboxylic acid, tere-phthalic acid, toluic acid, and benzoic acid. Decarboxylation of the total acid mixture was shown to afford benzene, toluene, Cj-benzenes (i.e., ethylbenzene or xylenes), Cj-benzenes, butylbenzenes, Cj-benzenes, Cybenzenes, naphthalene, methylnaphthalene, C2-naphthalene, biphenyl, methylbi-phenyl, C3-biphenyl, indane, methylindane, Cj-indane, phenanthrene, and fluorene. 

Biphenyl tetracarboxylic add dianhydride/phenylene diamine (BPDA-PDA) polyamic acid, 14.5% solids in N-methylpyrrolidone (NMP), TEF SOB, 60%... 

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