Tetrachloro-p-quinone

Tetrachloro-p-quinone (1.2 g) and 3-N,N-diethylaminophenol (1.80 g) were dissolved in 50 ml methyl alcohol, 4.2 ml 28% aqueous solution sodium methoxide added, and the mixture refluxed 6 hours. Thereafter, the mixture was extracted with CH2CI2, dried, and concentrated. The product was purified by chromatography on silica gel using chloroform/hexane and cis- and trans-products, 0.42 g and O.lOg, mp = 292 °C and 288 °C isolated, respectively. H-NMR and absorption maxima and coefficients data supplied. 

To cite another of the many possible examples, tetrachloro-p-quinone (chloranil) is transformed under similar conditions to give the hexachloro-p-diketone derivative (III). Hydrolysis of this para derivative with caustic soda caused the ring to break with formation of dichlormaleic acid, trichloroethylene, and sodium chloride as follows ... 

Tetrachloro-2,5-cyclohexadiene-1,4-dione Tetrachloroquinone Tetrachloro-p-quinone... 

Reacts with amines and alkali metals forming the corresponding water-soluble salts (Sanborn et al, 1977). Reacts with nitric acid forming a mixture of tetrachloro-o and p quinones (Monsanto, 1963). 

Stade observed an interesting oxidation with tetrachloro-p-benzoquinone. In methylene chloride an intense red coloration appears, but no signal in the ESR spectrum. Apparently only a charge-transfer complex 61 is formed, without electron transfer. A similar observation has been made in the reaction of N, N, N, N -tetramethyl-p-phenylenediamine with tetrachloro-p-benzoquinone in non-polar solvents Here, as in our case, electron transfer does not take place until a polar solvent such as acetonitrile is added. The ESR spectrum initially shows the doublet of 55 (23,2 Gauss) overlapping with the sharp sin et of tetrachloro-semi-quinone 62 (which has a somewhat smaller g factor). The semiquinone signal slowly disappears until finally only the doublet of 58 remains. The following scheme summarizes the reaction course ... 

A system has been proposed which involves quinone/hydroquinone interconversions. A number of such couples are insoluble in acid solution and can therefore be used as active solid masses when made conductive by the addition of graphite. A system which has been studied experimentally is based on anthraquinone, Q, and tetrachloro-p-benzoquinone (chloranil), Qr, and their reduced or hydroforms. The overall cell reactions are then... 

The reactions of P-halophospha-alkenes with carbenes provide a new route to 1-chloro-lH-phosphirines (181). Such compounds are highly reactive, and a study of nucleophilic displacement reactions at phosphorus has been facilitated by preparation of the related P-W(CO)5 complexes.The first pentacoordinate systems derived from phosphirenes, (182), have been formed in the reactions of P-halo- or P-cyano-phosphirenes with tetrachloro-o-quinone. Evidence has been presented for the rearrangement of P-chlorophosphirenium ions (183) to the vinylphosphenium ions (184)... 

Very selective oxidizing agents suitable for the conversion of primary alcohols into aldehydes are high-potential quinones such as tetrachloro-o-benzoquinone, tetrachloro-p-benzoqninone, and 2,3-dichloro-5,6-dicyano-p-benzoquinone [973]. Such dehydrogenations are carried out in chloroform, carbon tetrachloride, or ethanol, usually under very mild conditions at room temperature or in refluxing ether, and give fair to good yields (equation 216) [973]. 

Another route to Pd(0) complexes reported recently is by reaction of [Pd(CNPh)2] with activated monoolefins 18, 220). With fumaronitrile maleic anhydride and p-quinones, 1 1 adducts are formed, whereas, with tetrachloro-p-benzoquinone, an adduct is formed in which the Pd-to-ligand ratio is 2 1. Another new procedure is the use of bis-(dibenzlideneacetone) palladium(O) which reacts directly with olefins 145). 

Tetramethyl-tetralindione (73) Tetrachloro-o-quinone n-Butyraldehyde ), benzaldehyde 15>, anisaldehyde ls), />-chlorobenzaldehyde 151 Acetaldehyde Benzaldehyde 14 ), p-tolualdehyde 145>, anisaldehyde 145 cinnamaldehyde 14B>... 

Mixed donor ligands. The reaction of [Fe(salen)] with a range of quinones yields [(Fe(salen) 2(quin)] (quin = p-benzoquinone, tetramethyl-p-benzoquinone, and tetrachloro-p-benzoquinone) which probably contain quinone ligands. With 9,10-phenanthraquinone and 1,2-naphthaquinone, [Fe(salen)(quin)] is formed. The reactions of Fe(salen) with a variety of organic halides and nitro- and nitroso-compounds have been studied. With PhN02, [Fe (salen)20], and PhN(0)=NPh are formed whereas the PhNO reaction yields the same iron(iii) compound and PhN=NPh. Reaction with RNO (R = 2-biphenyl or... 

The first tetra-TTF calix[4] pyrrole conjugate 170 has been synthesized by the condensation of acetone and the corresponding monopyrrolo-TTF unit. This calix[4]pyrrole in its 1,3-altemate conformation acted as a host for neutral electron-deficient guests such as 1,3,5-trinitrobenzene, tetrafluoro-p-benzoquinone, tetrachloro-p-benzoquinone and p-benzo-quinone. The addition of chloride ions served to effect release of these guests and thus neutral substrate recognition process could be blocked by the addition of chloride anion (2004JA16296). 

Dehydrogenation. Tetrachlorocyclohexadienes are aromatized by quinones with high oxidation potentials as tetrachloro-p-benzoquinone (TCQ) or dichlorodicyano-p-benzoquinone (DDQ) (eq 14). ... 

The nucleophilic displacement of the halogen from 2,4-dinitrohalobenzenes by azide ion is catalysed by macrotricyclic ammonium salts [69], Kinetic studies indicate that the azide ion is entrapped and transported within the macrocyclic cage. The highly explosive tetra-azido-p-benzoquinone is obtained when the tetrachloro-quinone is reacted with an excess of sodium azide under phase-transfer catalytic conditions [70]. When only a twofold excess of the azide is used, the 2,5-diazido-3,6-dichloro compound is obtained. 

Dichloro-2-hydroxy-5-2, 4, 5, 6 -tetrachloro-3-hydroxyphenoxy-p-benzo-quinone, see... 

HjCat represents catechol or hydroquinone, Q quinone, SQ semiquinone anion, HCat- catechol monoanion, and Cat2 catechol dianion DTBQ represents 3,5-di-rerr-butyl-o-quinone, o-Q o-benzoquinone, p-Q p-benzoquinone, TCQ tetrachloro-o-benzoquinone, and TFQ tetrafluoro-o-benzoquinone. 

The photochemical addition of 9,10-phenanthraquinone, tetrachloro-1,2-benzoquinone (and benzil) to alkenynes (285) has been reported.167 The addition of the quinones takes place to the ethylenic bond of the alkenyne to yield alkynyl dioxins (286) and (287). The reaction is not stereospecific and a biradical intermediate is proposed to account for the loss of the stereochemical integrity of the olefin. Ishibe et a/.168 have published the results of an investigation of the photoaddition of p-benzoquinone, 1,4-naphthoquinone, 2-methyl-1,4-benzoquinone,... 

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