Benzenediols

J.M.J. Frechet (C. J. Hawker, 1990) replaced the divergent synthesis by a convergent growth of a dendritic polymer. The repeatedly employed monomer, 5-hydroxymethyl-l, 3-benzenediol, was 1,3-O-dibenzylatcd with 3,5-bis(benzyloxy)benzyl bromide. The resulting benzyl alcohol containing 7 benzene rings was converted to the benzyl bromide which was... 

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

Polyhydric phenols with more than two hydroxy groups (ie, the three positional isomers of benzenetriol, the three isomeric benzenetetrols, benzenepentol [4270-96-6] and benzenehexol [608-80-0]) are discussed in this article. The benzenediols are catechol, resorcinol, and hydroquinone (see Hydroquinone, RESORCINOL, AND CATECHOL). 

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). 

Benzenedisulfonic acid [831-59-4] (disodium salt), produced by the neutralization of the disulfonic acid with sodium sulfite [7757-83-7] is used in the manufacture of resorcinol [108-46-3] (1,3-benzenediol) (2), a chemical component found in mbber products and wood adhesives (72). The disodium salt is fused with sodium hydroxide, dissolved in water, and acidified to produce resorcinol, which is isolated via extraction (73). 

CA name (R)-(-)-4-[l-hydroxy-2-(methylamino)eth5l]-1,2-benze nediol (R)-(-)-4-(2-amino-1-hydroxyethyl)-1,2-benzenediol... 

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. 

Chemical Name 4-[1-hvdroxv-2-(methvlamino)ethyl]-1,2-benzenediol borate Common Name Methylaminoethanolcatechol borate adrenalin borate... 

Chemical Name 4-[1-hydroxy-2-[(1-methylethyl)amino] ethyl]-1,2-benzenediol sulfate Common Name Isoprenaline sulfate isopropylarterenol sulfate... 

Chemical Name 5-[1 -Hydroxy-2-[ (1 -methylethyDamino] ethyl] -1 -benzenediol sulfate Common Name Orciprenaline sulfate... 

Chemical Name 4-[2- [ [2-(1,3-benzodioxol-5-yl)-Tmethylethyll amino] -l-hydroxyethyl] -1,2-benzenediol... 

Safrole, a substance isolated from oil of sassafras, is used as a perfumery agent. Propose a synthesis of safrole from catechol (1,2-benzenediol). 

Efficient asymmetric transfer is also observed for 1,2-benzenediol induced reactions of a-sub-stituted (Z)- and ( ,)-allyl(trialkoxy)silanes prepared by hydrosilation of conjugated dienes, although in this case the electrophile attacks the C-C double bond of the allylsilane syn with... 

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. 

Dimethylpropylcyanobetene can be prepared in an analogous fashion starting from the commercially available 2,5-bis(l,l-dimethyl-propyl)-l,4-benzenediol. This ketene seems to be very similar in stability and reactivity to its [Pg.38]

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. 

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