Fumaric acid, dihydroxy

Fumaric acid Pentanedioic acid 2- Pentanedioic acid 27 3,4-Dihydroxy benzoic add... 

Addition of a small proportion of iron (II) sulfate to D-tartaric acid-hydrogen peroxide causes rapid conversion into a product closely related to dihydroxymaleic acid. Occurrence of a reaction with substituted hydrazines indicates the presence of a keto acid (1), and isolation of a diacetate and a dibenzoate favors the hypothesis of formation of dihydroxy-fumaric acid (2). On the basis of pH studies, Hatcher and Sturrock ... 

In some cases, one of the precursors contributes to the formation of both the hard and the soft blocks. Aleksandrovic and Djonlagic [23] copolycondensed a mixture of diesters of terephthalic and fumaric acids, 1,4-butanediol and a,o>-dihydroxy-poly(oxytetramethylene) in the presence of tetrabutoxytitanium... 

Ascorbic acid serves as a reductant with phenolase or in the dopamine hydroxylating system, while tetrahydropteridine is the immediate electron donor in the phenylalanine hydroxylase system. In the latter case TPNH is serving as a reductant indirectly because the oxidized pteridine derivative produced in the hydroxylation reaction is reduced by a TPNH-linked system (Kaufman, this volume, Chapter4). Dihydroxy-fumaric acid serves as an electron donor in the peroxidase-catalyzed non-specific aromatic hydroxylating system (Mason, 1957b). 

The pnndpal unsaturated acids used are maleic and fumaric. Saturated acids, usually phthahe and adipic, may also be included. The function of these acids is to reduce the amount of unsaturation in the final resin, making it tougher and more flexible. The acid anhydrides are often used if available and applicable. The dihydroxy alcohols most generally used are ethylene, propylene, diethylene, and dipropylene glycols. Styrene and diallyl philialate are the most common cross-linking agents, Polyesters are resistant to corrosion, chemicals, solvents, etc. 

Osmium tetroxide is also a catalyst in the oxidation of the double bond by chlorates. Cis addition of hydroxyl groups takes place as is shown by the preparation of cis-l,2-cyclohexanediol from cyclohexene and the formation of the proper diastereoisomeric dihydroxy derivatives of maleic, fumaric, and 4-halocrotonic acids. Silver chlorate is preferred to potassium chlorate in the hydroxylation of crotonic acid. ... 

The Diels-Alder reactions of cyclopentadiene with the unsymmetrical maleates or fumarates of axially chiral 8,8 -dihydroxy-l,l -binaphthalene have been investigated under different conditions in the presence of a Lewis acid [107]. Diastereo- and endol exo selectivity depends on the Lewis aeid used. High diastereoselectivity has been achieved with TiCl(0/-Pr)3 for the endo adduct of the maleate (Eq. 68), and with... 

Irans-cyclohexanedimethanol hir-(p-carboxyphenoxy)propane 9,10-dihydroxy-stearic acid desaminotyrosyl-tyrosine hexyl ester 1,6-hexanediol peak molecular weight weight average molecular weight oligo(poly(ethylene glycol) fumarate) poly(Bisphenol A) poly(trani-cyclohexanedimethanol-co-, 6-hexanediol) poly(E-caprolactone) poly(h -(p-carboxyphenoxy)propane) poly(h/s-(p-carboxyphenoxy)propane-co-sebacic acid)... 

The amount of gases liberated from these polymers constitutes 20% of the initial weight at 500°C. For polyarylates based on 4,4 -dihydroxy-diphenyl-2,2 -propane with fumaric and sebacic acids, appreciable gas evolution begins at only 300 °C. 

Nitrones activated by chiral 2,2 -dihydroxy-l,P-bisnaphthol (BINOL)-AlMe complexes undergo enantioselective inverse-electron-demand 1,3-dipolar cycloaddition reactions with electron-rich alkenes to produce exo-diastereoisomers of isoxazolidines. The diastereoselectivity of the 1,3-dipolar cycloaddition between diphenyl nitrone and 4-(5 )-benzyl-( )-but-2 -enoyl)-l,3-oxazolidin-2-one can be controlled by inorganic salts whose cations behave like Lewis acids.The Cu(OTf)2-bisoxazoline-catalysed asymmetric 1,3-dipolar cycloaddition of nitrones with electron-rich alkenes at room temperature gave isoxazolidines in good yields and diastereoselectivity and with high enantioselectivities of up to 94% ee. ° Kinetic studies have shown that the reaction rate of the 1,3-dipolar cycloaddition of C,tV-diphenyl nitrone with dibutyl fumarate increases dramatically in aqueous solutions... 

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