Succinic acid anhydrides 2 molecules

Friedel-Crafts Acylation. The Friedel-Crafts acylation procedure is the most important method for preparing aromatic ketones and thein derivatives. Acetyl chloride (acetic anhydride) reacts with benzene ia the presence of aluminum chloride or acid catalysts to produce acetophenone [98-86-2], CgHgO (1-phenylethanone). Benzene can also be condensed with dicarboxyHc acid anhydrides to yield benzoyl derivatives of carboxyHc acids. These benzoyl derivatives are often used for constmcting polycycHc molecules (Haworth reaction). For example, benzene reacts with succinic anhydride ia the presence of aluminum chloride to produce P-benzoylpropionic acid [2051-95-8] which is converted iato a-tetralone [529-34-0] (30). 

Glutaric acid is a linear, five carbon molecule with carboxylic acid groups on both ends. It contains one additional carbon in length than the similar compound succinic acid. The anhydride... 

Maleic acid is a linear four carbon molecule with carboxylate groups on either end similar to succinic acid, but with a double bond between the central carbon atoms. The anhydride of maleic... 

Maleic acid is a linear four-carbon molecule with carboxylate groups on either end, similar to succinic acid, but with a double bond between the central carbon atoms. The anhydride of maleic acid is a cyclic molecule containing five atoms in its ring. Although the reactivity of maleic anhydride is similar other such reagents like succinic anhydride, the products of maleylation are much more unstable toward hydrolysis, and the site of unsaturation lends itself to additional side reactions. Acylation products of amino groups with maleic anhydride are stable at neutral pH and above, but they readily hydrolyze at acid pH values (around pH 3.5) (Butler etal., 1967). Maleylation of sulfhydryls and the phenolate of tyrosine are even more sensitive to hydrolysis. 

The mechanisms of modification are different and depend on the chemical molecules used for the reactions. The anhydride of succinic acid reacts with lysine residues, a-amino groups of proteins and free thiol groups. During succinylation, proteins lose their globular structure and undergo aggregation by disulfide cross-binding with other whey proteins. Acetyl anhydride can modify tyrosine residues. 

IV.42 SUCCINATES, C4H402 Solubility Succinic acid, HOOC.CH2. CH2.COOH or H2.C4H404 (a dibasic acid), is a white, crystalline solid with a melting point of 182° it boils at 235° with the formation of succinic anhydride, C4H403, by the loss of one molecule of water. The acid is fairly soluble in water (68 4 g -1 at 20°), but more soluble in hot water it is moderately soluble in alcohol and in acetone, slightly soluble in ether, and sparingly soluble in chloroform. Most normal succinates are soluble in cold water the silver, calcium, barium, and basic iron(III) salts are sparingly soluble. 

Succinic acid, however, forms an anhydride by the loss of one molecule of water from one molecule of the acid, as follows ... 

Introduction. The object of this experiment is to illustrate two general methods for the preparation of acid anhydrides. Two carboxyl groups may under certain conditions be dehydrated to give an anhydride. The two carboxyl groups may be derived from the same molecule, as in succinic and phthalic anhydrides, or from different molecules, as in acetic anhydride. The simple anhydrides are usually prepared in the laboratory by the action of an acyl chloride on the salt of the acid ... 

An anhydride is formed by coupling two COOH units, derived from two carboxylic acids (see Section 20.4). Because a dicarboxylic acid has two COOH units, it is possible to couple these units intramolecularly to form a cyclic anhydride. The smallest commonly observed cyclic anhydride formed contains five atoms formed by heating succinic acid (152). Loss of a molecule of water leads... 

Hydroxamic acids are an important class of compounds targeted as potential therapeutic agents. A-Fmoc-aminooxy-2-chlorotrityl polystyrene resin 61 allowed the synthesis and subsequent cleavage under mild conditions of both peptidyl and small molecule hydroxamic acids (Fig. 14) [70]. An alternative hydroxylamine linkage 62 was prepared from trityl chloride resin and tV-hydroxyphthalimide followed by treatment with hydrazine at room temperature (Scheme 30) [71]. A series of hydroxamic acids were prepared by the addition of substituted succinic anhydrides to the resin followed by coupling with a variety of amines, and cleavage with HCOOH-THF(l 3). 

Imide.—When ammonium acid succinate is heated water is lost in two steps. First, succinamic acid is obtained and then an anhydride compound. The same compound is also obtained when the symmetrical di-amide is heated and a molecule of ammonia is lost. The compound has been shown to have an inner anhydride structure exactly analogous to succinic anhydride and is known as succin-imide. The reactions may be represented as follow ... 

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