Fumarate fumaric acid

Diethyl fumarate Fumaric acid, diethyl ester (8) 2-Butenedioic acid ( )-, diethyl ester (9) (623-91-6)... 

Fig. IS. 12. Spectra showing changes in absorption due to C—O stretching during reaction of fumarase on 1.0 Af sodium fumarate-fumaric acid (0.04 mg enzyme/ ml). Observed absorption maxima are at 1093 and 1220...

Fig. 15.13. Spectra showing changes in absoqition due to out-of-plane deformations of the trans-hydrogens during reaction of fumarase on l.OM sodium fumarate-fumaric acid in DjO (pH 7.3, 0.04 mg enzyme/ml).

Synonyms Di-n-butyl fumarate Fumaric acid, dibutyl ester Empirical C12FI20O4... 

Fumaric acid, diallyl ester. See Diallyl fumarate Fumaric acid, dibutyl ester. See Dibutyl fumarate Fumaric resin. See Maleic resin Fumed silica Fumed silicon dioxide. See Silica, fumed Fural 2-Furaldehyde Furale. See Furfural... 

CAS 19139-31-2 EINECS/ELINCS 242-833-4 Synonyms 2-Butenedioic acid (E)-, dihexyl ester Dihexyl trans-2-butenedioate Di-n-hexyl fumarate Fumaric acid, dihexyl ester... 

Colourless prisms m.p. 130 C. Manufactured by treating maleic anhydride with water. It is converted to the anhydride by heating at By prolonged heating at 150 "C or by heating with water under pressure at 200 C, it is converted to the isomeric (trans) fumaric acid. Reduced by hydrogen to succinic acid. Oxidized by alkaline solutions of potassium permanganate to mesotartaric acid. When heated with solutions of sodium hydroxide at 100 C, sodium( )-malate is formed. Used in the preparation of ( )-malic acid and in some polymer formulations. 

Racemic acid, ( )-tartaric acid, is a compound of the two active forms. M.p. 273 C (with IHjO), m.p. 205°C (anhydrous). Less soluble in water than (-t-)-tartaric acid. Formed, together with mesotartaric acid, by boiling (4-)-tartaric acid with 30% NaOH solution, or by oxidation of fumaric acid. Potassium hydrogen racemate is very insoluble. 

Upon heating with hydrochloric acid, maleic acid, m.p. 144°, is converted into fumaric acid, m.p. 287° ... 

Both acids 3deld succinic acid, m.p. 185°, upon catalytic reduction (see Section 111,150), thus establishing their structures. Maleic and fumaric acids are examples of compounds exhibiting cis-trans isomerism (or geometric isomerism). Maleic acid has the cm structure since inter alia it readily 3delds the anhydride (compare Section 111,93). Fumaric acid possesses the trans structure it does not form an anhydride, but when heated to a high temperature gives maleic anhydride. 

Fumaric acid is conveniently prepared by the oxidation of the inexpensive furfural with sodium chlorate in the presence of a vanadium pentoxide catalyst ... 

B. Conversion of maleic acid into fumaric acid. Dissolve 10 g. of maleic acid in 10 ml. of warm water, add 20 ml. of concentrated hydrochloric acid and reflux gently (provide the flask with a reflux condenser) for 30 minutes. Crystals of fumaric acid soon crystaUise out from the hot solution. Allow to cool, filter oflF the fumaric acid, and recrystallise it from hot. A -hydrochloric acid. The m.p. in a sealed capillary tube is 286-287°. 

C. Fumaric acid from furfural. Place in a 1-litre three-necked flask, fitted with a reflux condenser, a mechanical stirrer and a thermometer, 112 5 g. of sodium chlorate, 250 ml. of water and 0 -5 g. of vanadium pentoxide catalyst (1), Set the stirrer in motion, heat the flask on an asbestos-centred wire gauze to 70-75°, and add 4 ml. of 50 g. (43 ml.) of technical furfural. As soon as the vigorous reaction commences (2) bvi not before, add the remainder of the furfural through a dropping funnel, inserted into the top of the condenser by means of a grooved cork, at such a rate that the vigorous reaction is maintained (25-30 minutes). Then heat the reaction mixture at 70-75° for 5-6 hours (3) and allow to stand overnight at the laboratory temperature. Filter the crystalline fumaric acid with suction, and wash it with a little cold water (4). Recrystallise the crude fumaric acid from about 300 ml. of iif-hydrochloric acid, and dry the crystals (26 g.) at 100°. The m.p. in a sealed capillary tube is 282-284°. A further recrystaUisation raises the m.p. to 286-287°. 

A small quantity (ca. 3 g.) of fumaric acid may be recovered from the 6ltrate by heating it on a water bath with 15 ml. of concentrated hydrochloric acid, evaporating to about 150 ml., and then cooling with running water. The fumaric acid which separates is recrystallised from N-hydrochloric acid. 

Crotonic acid exists in cis and trans forms (compare maleie and fumaric acids) CH3—C—H CH3—C—H... 

The diethyl fumarate is readily prepared as follows. Reflux a mixture of 146 g. of fumaric acid (Section 111,143), 185 g. (236 ml.) of absolute ethanol, 450 ml. of boizene and 20 g. of concentrated sulphuric acid for 12 hours. Pour into a large volume of water, separate the benzene layer, wash successively with water, saturated lodium bicarbonate solution and water, dry with anhydrous magnesium sulphate, and remove the solvent on a steam bath. Distil the residue and collect the diethyl fumarate at 213-215° the yield is 150 g. 

Supplement II, 2nd 1929 152-194 Oxalic acid, 502. Succinic acid, 601. Fumaric acid, 737... 

The biological dehydrogenation of succinic acid described in Section 5 8 is 100% stereoselective Only fumaric acid which has a trans double bond is formed High levels of stereoselectivity are characteristic of enzyme catalyzed reactions... 

Optically inactive starting materials can give optically active products only if they are treated with an optically active reagent or if the reaction is catalyzed by an optically active substance The best examples are found m biochemical processes Most bio chemical reactions are catalyzed by enzymes Enzymes are chiral and enantiomerically homogeneous they provide an asymmetric environment m which chemical reaction can take place Ordinarily enzyme catalyzed reactions occur with such a high level of stereo selectivity that one enantiomer of a substance is formed exclusively even when the sub strate is achiral The enzyme fumarase for example catalyzes hydration of the double bond of fumaric acid to malic acid m apples and other fruits Only the S enantiomer of malic acid is formed m this reaction... 

The reaction is reversible and its stereochemical requirements are so pronounced that neither the cis isomer of fumaric acid (maleic acid) nor the R enantiomer of malic acid can serve as a substrate for the fumarase catalyzed hydration-dehydration equilibrium... 

Unsaturated Polyesters. Unsaturated polyesters are produced by reaction between two types of dibasic acids, one of which is unsaturated, and an alcohol to produce an ester. Double bonds in the body of the unsaturated dibasic acid are obtained by using maleic anhydride or fumaric acid. 

Description of Method. Salt substitutes, which are used in place of table salt for individuals on a low-sodium diet, contain KCI. Depending on the brand, fumaric acid, calcium hydrogen phosphate, or potassium tartrate also may be present. Typically, the concentration of sodium in a salt substitute is about 100 ppm. The concentration of sodium is easily determined by flame atomic emission. Because it is difficult to match the matrix of the standards to that of the sample, the analysis is accomplished by the method of standard additions. 

TALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15)... 

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