Benzenediol

Section 24 14 Oxidation of 1 2 and 1 4 benzenediols gives colored compounds known as qumones... 

The close electrochemical relationship of the simple quinones, (2) and (3), with hydroquinone (1,4-benzenediol) (4) and catechol (1,2-benzenediol) (5), respectively, has proven useful in ways extending beyond their offering an attractive synthetic route. Photographic developers and dye syntheses often involve (4) or its derivatives (10). Biochemists have found much interest in the interaction of mercaptans and amino acids with various compounds related to (3). The reversible redox couple formed in many such examples and the frequendy observed quinonoid chemistry make it difficult to avoid a discussion of the aromatic reduction products of quinones (see Hydroquinone, resorcinol, and catechol). 

Chemical Designations - Synonyms 1,4-Benzenediol p-Dihydroxybenzene Hydroquinol Pyrogentisic acid Quinol Chemical Formula 1,4-CjH4(OH)2. 

The three dihydroxy derivatives of benzene may be naned as 1,2-, 1,3-, and 1,4-benzenediol, respectively, but each is more faniliaily known by the common nane indicated in parentheses below the structures shown here. These common names are permissible lUPAC nfflnes. 

Benzenediol, quinol, or p-dihydroxy benzene [CgH4-l,4-(OH)2] has a MW of 110.1. It is a white crystalline powder formed by the reduction of p-benzoquinone [quinone, CgH4 ( 0)2],... 

Cyclopentadiene was prepared2 by heating dicyclopentadiene (purchased from Eastman Organic Chemicals) and a pinch of hydro-quinone (1,4-benzenediol) under a column of glass helices or a Vigreux column at 175° and collecting the distillate in a receiver cooled with a 2-propanol-dry ice bath. The monomer was dried over Linde 4A Molecular Sieves at —20° and could be stored at this temperature for several weeks without excessive dimerization. 

Pure (A)-1 -chloropropene was obtained by careful distillation of a mixture of (E)- and ( )-l -chloropropene (available from Columbia Organic Chemicals Company Inc.) using a Nester-Faust Teflon annular spinning band column [(Z)-l-chloropropene has b.p. 33° (A)-l-chloropropene has b.p. 37°]. Small quantities of powdered sodium bicarbonate and hydroquinone (1,4-benzenediol) placed in the distillation flask inhibit acid-catalyzed isomerization and polymerization. Gas chromatographic analysis of the material used in these experiments on a 4-m., 15% l,2,3-tris(2-cyanoethoxy)propane (TCEP) on Chromosorb P column, operated at room temperature, typically indicated that it had isomeric purity >99.9%. (A)- 1-Chloropropene is stable for several months at room temperature, but it should be stored in a cool place. 

Our recent studies on effective bromination and oxidation using benzyltrimethylammonium tribromide (BTMA Br3), stable solid, are described. Those involve electrophilic bromination of aromatic compounds such as phenols, aromatic amines, aromatic ethers, acetanilides, arenes, and thiophene, a-bromination of arenes and acetophenones, and also bromo-addition to alkenes by the use of BTMA Br3. Furthermore, oxidation of alcohols, ethers, 1,4-benzenediols, hindered phenols, primary amines, hydrazo compounds, sulfides, and thiols, haloform reaction of methylketones, N-bromination of amides, Hofmann degradation of amides, and preparation of acylureas and carbamates by the use of BTMA Br3 are also presented. 

The reaction of 1,4-benzenediols with an equimolar amount of BTMA Br3 in dichloromethane in the presence of aq. sodium acetate at room temperature gave 2,5-cyclohexadiene-l,4-diones in good yields. On the other hand, the reaction of 1,4-benzenediols with a large excess of the agent in aq. acetic acid at 40-60°C gave polybromo-substituted products (Fig. 25) (ref. 33). 

Benzenediol-oxygen complex (Hydroquinone-oxygen clathrate)... 

See Silver nitrate Ammonia, Sodium hydroxide 1,4-Benzenediol... 

Benzenediol, h86 Benzenemethanol, b78 1,2,3-Benzenetriol, t317 Benzenethiol, tl 56 Benzhydrazide, b71 Benzhydrol, d760 Benzhydrylamine, d761... 

Cyclohexadiene-l,4-dione with 1,4-benzenediol (1 1), ql Cyclohexaneacetic acid, c373... 

Aluminium, 0048 Ammonium phosphinate, 4554 Barium phosphinate, 0210 f Benzaldehyde, 2731 1,4-Benzenediol, 2333 Bis(hydrazine)tin(II) chloride, 4070 Calcium acetylide, 0585 Calcium phosphinate, 3931 Chromium(II) chloride, 4052 Chromium(II) oxide, 4241 Chromium(II) sulfate, 4244 Copper(I) bromide, 0265 Diacetatotetraaquocobalt, 1780 Diisobutylaluminium hydride, 3082 f 1,2-Dimethylhydrazine, 0955... 

Synonyms AI3-00072 Arctuvin p-Benzenediol 1,4-Benzenediol Benzohydroquinone Benzoquinol Black and white bleaching cream BRN 0605970 CCRIS 714 Dihydroxybenzene jO-Dlhydroxybenzene 1,4-Dihydroxybenzene p-Dioxobenzene EINECS 204-617-8 Eldopaque Eldoquin HQ Hydroquinol Hydroquinole a-Hydroquinone p-Hydroquinone 4-Hydroxy-phenol p-Hydroxyphenol NC1-C55834 NSC 9247 Quinol p-Quinol Quinone Tecquinol Tenox HQ Tequinol UN 2662 USAF EK-356. 

Benzenediol, see Hydroquinone p-Benzenediol, see Hydroquinone Benzeneformic acid, see Benzoic acid Benzene hexachloride, see Lindane Benzene hexachloride-a-isomer, see a-BHC Benzene-crs-hexachloride, see p-BHC Benzene-y-hexachloride, see Lindane a-Benzene hexachloride, see a-BHC p-Benzene hexachloride, see p-BHC 6-Benzene hexachloride, see 8-BHC y-Benzene hexachloride, see Lindane frans-a-Benzene hexachloride, see p-BHC Benzene hexahydride, see Cyclohexane Benzene methanoic acid, see Benzoic acid Benzene methanol, see Benzyl alcohol Benzene tetrahydride, see Cyclohexene Benzenol, see Phenol... 

D-Erythrose undergoes self-aldolization in alkali solution, to form d- / co-L- /3 C6 TO-3-octulopyranose by combination of the 1,2-enediol and aldehyde forms. In weak alkali at 105°, syrupy D-erythrose yields d- /ycero-tetrulose, jS-D-a/tro-L-g/ycero-l-octulofuranose, and a-Ti-gluco-i -g/ycero-3-octulopyranose. At 300° in alkali, the major products from syrupy D-erythrose were 1-5% of butanedione (biacetyl) with smaller proportions of pyrocatechol, 33, 2,5-dimethyl-2,5-cyclohexadiene-l,4-dione (2,5-dimethylbenzoquinone), and 2,5-dimethyl-1,4-benzenediol (2,5-dimethylhydroquinone). It was assumed that D-erythrose is reduced to erythritol by a Cannizzaro type of reaction, followed by dehydration of erythritol to form biacetyl. However, very low proportions (<1%) of biacetyl are formed from erythritol compared with D-erythrose itself. Apparently, some other mechanism predominates in the formation of biacetyl. 

Synonyms 1,4-Benzenediol 1,4-dihydroxy-benzene p-hydroxybenzene hydroquinol quinol Tecquinol... 

P-Azo-[2-methyl-1,2-dicarbadecaborane( 14)], 2624 2-Azoxyanisole, 3653 1,4-Benzenediol-oxygen complex, 2334 Benzeneperoxy sulfonic acid, 2341 Benzeneseleninic acid, 2335 Benzeneseleninic anhydride, 3495 Benzenethiol, 2344 2,2 -Bi-l,3-dithiole, 2215 2,2 -Bipyridyl 1-oxide, 3258 Bis(cyclopentadienyl)lead, 3294 Bis-A(imidosulfurdiiluoridato)mercury, 4342 Bismuth trisulfide, 0234... 

Hydroquinone, Hydroquinol, 1,4-Benzenediol or p-Dihydroxybenzene (Hydrochinon in Ger). See 1,4-Dihydroxybenzene in Vol 5 of Encycl, p D1270-R... 

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