Oxidative biphenylenes

Synonyms AI3-00039 AIDS-18166 (l,r-Biphenyl)-2,2 -diyl oxide Biphenylene oxide 2,2 -Biphenylene oxide CCRIS 1436 CPD-926 Dibenzo[Ac/ furan Dibenzol[Ac/ furan Diphenylene oxide EINECS 205-071-3 NSC 1245. 

Some biphenylene end-capped polyquiaolines have been used to make carbon-fiber rekiforced composites (102). However, properties of these composites dropped off significantly when oxidatively aged for 50—100 h at 316°C. 

We then focused our attention to the cationic species generated from a series of condensed aromatics fully annelated with BCO units. Newly synthesized naphthalene 12 (17), anthracene 13 (18), biphenylene 14 (19), and fluorene 15 (20) all underwent smooth one-electron oxidation by the use of 1.5... 

Oxidation of 1-aminobenzotriazole (283) among other products results in the formation of bistriazolo compound 284. This reaction involves a benzene intermediate and illustrates an example wherein IBD behaves differently than lead tetra-acetate, which in this case gives biphenylene [80JCR(S)303] (Scheme 71). 

Chlorexolone as diuretic, 1, 174 Chlorides synthesis, 1, 448 Chlorin, 4, 370 metal chelates, 4, 391 Chlorin, dihydroxy-, 4, 393 Chlorin e6, 4, 404 trimethyl ester, 4, 398 synthesis, 4, 416 Chlorination pyridazines, 3, 20, 21 Chlorine trifluoride bonding, 1, 564 Chlorin-phlorin, 4, 398 Chlorins, 4, 378 absorption spectra, 4, 389 formation, 4, 394 molecular structure, 4, 385 oxidation, 4, 395 Chlorisondamine chloride as hypertensive agent, 1, 176 Chlormethiazoles metabolism, 1, 235 Chlormethiuron against ectoparasites veterinary use, 1, 217 Chlormezanone as antidepressant, 1, 169 Chlorocruoroheme, 4, 380 Chlorofucin conformation, 7, 703 Chloronium iodide, biphenylene-reactions, 1, 566... 

The IOji dibenzocyclobutadiene dication 227 was prepared472 by the two-electron oxidation of biphenylenes in excess of SbF5-S02ClF solutions at — 10°C, and the octamethyl derivative 228 was also generated under similar conditions.473... 

Biphenylene is commercially available but expensive. It is obtained by several methods one of the best, in spite of the low yield, involved pyrolysis of dibenziodolium iodide in the presence of cuprous oxide. 

Dibenzotellurophene 7e-oxide and 2,2 -dilithiobiphenyl in diethyl ether combine to produce bis[2,2 -biphenylene] tellurium4. 

Yamashiro S (1941), Bull. Chem. Soc. Japan 16 6-15. Studies on the derivatives of biphenylene oxide. V. Bromoderivatives of biphenylene oxide" van Zorge JA., van Wijnen JH., Theelen RMC, Olie K., van den Berg M (1990), Chemosphere, 19 1881-1895. Assessment of the Toxicity of Mixtures of Halogenated Dibenzo-p-dioxins and Dibenzofurans by Use of Toxicity Equivalency Factors (TEF) . 

Yamashiro S (1941), Bull. Chem. Soc. Japan 16 6-14.. .Studies on the derivatives of biphenylene oxide. V. Bromo derivatives of biphenylene oxide"... 

The reaction of 2,2 -dilithiobiphenyl, or the analogous Grignard reagent, with excess copper(II) chloride gave a mixture of products from which biphenylene and o-tetraphenylene were isolated 235, 304). Other products were tetra- and octaphenyls. The reaction was explained in terms of the formation of a copper(II) ate complex (IX) which, under the influence of further Cu " " ions, oxidatively couples to give a 60%... 

A number of catalytic reactions involve CC bond cleavage, often driven by strain. For example, " biphenylene can be converted to tetraphenylene with Ni(cod)(PMe3)2 at 100 °C or Pt(PR3)3 at 120 °C (equation 14). In the Pt case, a series of intermediates could be isolated that suggest a pathway involving double oxidative addition of the biphenylene CC bond, as in the stoichiometric reactions previously discussed, followed by double reductive elimination to give the product. 

The oxidative cyclization by copper(II) chloride of the ketone diolate derived from 1,8 diacetylbiphenylene (equation 12) represents a key step in the preparation of cycloocta [rfe/] biphenylene-1,4-dione (25) . 

Nitric acid oxidizes (2) to 5-tert-butyl-Z3-diphenyltetra/olium nitrate (3). which on irradiation yields 5-/cr/-butyl-2,3-[2,2 -biphenylene]tetrazolium nitrate (4). Sodium hydrosulfitc reduces (4) to the deep blue radical (5). 

Maruoka has successfully developed a highly accelerated Oppenauer oxidation [31,32] system using a bidentate aluminum catalyst [29]. This modified, catalytic system effectively oxidizes a variety of secondary alcohols to the corresponding ketones as shown in Sch. 9. For example, reaction of (2,7-dimethyl-l,8-biphenylene-dioxy)bis(dimethylaluminum) (8, 5 moI%) with carveol (14) at room temperature in the presence of 4-A molecular sieves, and subsequent treatment with pivalaldehyde (3 equiv.) at room temperature for 5 h yielded carvone (15) in 91 % yield. Under these oxidation conditions, cholesterol (16) was converted to 4-cholesten-3-one (17) in 75 % yield (91 % yield with 5 equiv. t-BuCHO). 

The alkaloids ningalin A-D were first isolated in 1997 by Fenical and Kang from the marine ascidian of the genus Didemnum sp. collected in western Australia near Ningaloo Reef. By far the most complex of these four alkaloids is ningalin D (1) incorporating a biphenylene qui-none methide superimposed on an oxidized pentasubstituted pyrrole core that characterizes this class of natural products. 

In the second step an oxidation of the diamine to the biphenylene quinodiimide and subsequent imine hydrolysis occur. 

In the second step diamine 38 is heated in a mixture of THF and water under an air atmosphere. In this way, the oxidation of diamine 38 to the biphenylene quinodiimide 39 occurs and this is subsequently hydrolyzed to provide permethyl ningalin D 22. 

Synonyms 2,2 -Biphenylene oxide 2,2 -bipheny-lylene oxide dibenzo(B,D)furan diphenylene oxide... 

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