Inner anhydrides

Preparation 491.—Diazobenzenesulphonic Acid Anhydride (Inner salt of bcnzenediazonium-hydroxide-i-sulphonic Acid). 

Lactones, which may be regarded as cyclic or inner esters, react similarly. Anhydrides of carboxylic acids also react with hydroxylamine to form hydroxamic acids ... 

The preparation of these [4-hydroxy-THISs, (1), X = O] by cydization of a-carboxy-N-arylthiobenzimides (5) by treatment with acetic anhydride and triethylamine has been investigated in detail, and the structure has been revised for the compound previously described as 2.3-diphenyl-4-hydroxythiazolium hydroxide inner salt (1, X = 0, R = R = Ph, R = H) (Scheme 5) (3, 10). 4-Hydroxy-THlSs also arise by condensation of gem-dicyanoepoxides with thioamides (Scheme 6) (8). 

Hydroxvthiazolium hydroxide inner salts (2) (X = 0) have been synthesized by an improved acetic-anhydride-triethylamine-caialyzed cyclization of N-substituied N-thiobenzovlalanines (Scheme 15) (23). 

Chloroform combines with the inner anhydride of salicyclic acid to form a well-defined crystalline double compound (12) ... 

The hydiobiomides of /3-y unsaturated acids like /S-phenyl-crotonic acid beha e Cjuite differently. On l oiling with water, lactones are formed, i.e., inner anhydrides of o. y-acids,... 

The investigation on the use of K-10 montmorillonite under free solvent conditions was then extended to inner ring dienes such as furan and its 2,5-dimethyl derivative [9] (Table 4.3). The cycloadditions generally proceed slowly, and Zn(II)-doped clay and microwave irradiation were used to accelerate the reactions. The reaction with maleic anhydride preferentially affords the thermodynamically favored exo adduct. 

The graphitic layers remain unchanged while the pore volume increases [93, 94]. Toebes et at. showed that the most predominant effect is the opening of the inner tubes of the fibers [93]. The oxidation did not only occur at the surface but also developed 2-3 run into the subsurface [93]. Carbonyl groups are formed, which are subsequently converted into carboxyls and carboxylic anhydrides [92]. 

Triazines 113 reacted with dimethyl acetylenedicarboxylate in acetic acid-acetic anhydride to give pyridotriazines 114 and minor quantities of the inner salts 115, which were too unstable to purify (77LA1421). 

Among the NO-donor mesoinoic heterocycles, the sydnonimines have attracted by far the most interest. They were first obtained by Brookes et al. [78] and Kato et al. [79] by the action of nitrous fumes on a-( N-rnelh yl-N-riilrosoamino)-nitriles followed by the action of acetic anhydride. Whereas sydnones represent a family of stable heterocycles, sydnonimines, with the exception of 3-hydroxysydnonimine (81, R=OH, Ri =H) that forms an inner salt [80], are unstable if not protonated to a salt or acylated to stable N-acylimino derivatives. In this case they can be stored at room temperature... 

Although the polyhydric alcohols derived from sugars have been the subject of numerous investigations over many years, the inner ethers or anhydrides of these substances have been for the most part neglected, despite the fact that many of them were isolated and some description of their properties recorded before the advent of the twentieth century. In recent years, however, the anhydrides of polyhydric alcohols derived from sugars have received marked attention in several countries. Some indeed have achieved importance in chemical industry. Most interest has been centered on the anhydrides of pentitols and hexitols and this article will be restricted to a discussion of the chemistry of these substances. 

Isatin is the inner anhydride (lactam) of a y-amino-a-ketocarboxylic acid, isatinic acid (A), and is converted into a salt of this acid by the action of alkali. The keto-group in position 3 can condense with many other substances, and for this reason isatin is manufactured on a technical scale and converted into valuable indigoid vat dyes. The magnificent thioindigo scarlet, which is obtained from isatin and a sulphur analogue of indoxyl (the so-called hydroxythionaphthene), may be taken as example qq... 

After uptake by the cell, fatty acids are activated by conversion into their CoA derivatives—acyl CoA is formed. This uses up two energy-rich anhydride bonds of ATP per fatty acid (see p. 162). For channeling into the mitochondria, the acyl residues are first transferred to carnitine and then transported across the inner membrane as acyl carnitine (see B). 

Alkylation of ll-mercaptopyrido[l,2-h]cinnolin-6-ium hydroxide inner salts (e.g., 41) with ethyl bromoacetate gave ll-(ethoxycarbonylmethyl(thio derivatives 64 (R = H), which could be hydrolyzed to the ll-(carboxy-methyl)thio derivative or back to the starting compound 41 (74JHC125). Hydrolysis of the ll-bis(methoxycarbonyl)methylene 66 (R = H), and 2-cyano derivatives of 17 (R = H) in boiling HCl afforded 11-methyl and 2-carboxylic acid derivatives, respectively (74JHC125). The 2-nitro derivative of 17 (R = H) was reduced to the 2-amino derivative over Pd/C with NaBH4 in aqueous methanol, and the 2-amino group was acylated with acetic anhydride at 100°C. 

Weigh a sample, transfer it to a round-bottom flask equipped with a reflux condenser cooled with tap w and introduce through the inner tube of condenser, a quantity of acetic anhydride slightly in excess of that required for acetylation. After introducing through the condenser an amt of pyridine = to ca 10% of acetic anhydride, the reaction of acetylation starts spontaneously and then procedes at a much slower rate. The following reaction takes place ... 

Ill an inner compound an additional valence hnnd has been formed between two atoms of an already existing structure, usually by loss of ihe elements of water or other simple substance. Inner compound formation commonly results in the formation of a ring. The inner esters, inner anhydrides, and inner coordination compounds are well-known classes of inner compounds. 

A. Itaconic Anhydride A 500-cc. Pyrex Kjeldahl flask is fitted with an outlet tube 12 mm. in diameter bent for downward distillation. It is attached to a 100-cm. water-cooled condenser having an indented Pyrex inner tube (Note 1). Two 250-cc. long-neck distilling flasks are used in series as receivers, the vapors being led to the center of each flask by means of an adapter and glass tubing. Both receivers are cooled in a mixture of ice and water. 

Encycl) with a binder (such as epoxy-polyamide, expoxy-anhydride, and polyurethane resins) and loading the resulting mixture into the annulus between the inner and outer parts of a cylindrical mold. After curing for 24hr, this cylindrical part of cartridge was attached to a noncombustible base(metallic or plastic), which served as an obturator... 

Lowering the reaction temperature or adding urea or basic solvents decreases the extent of chlorination. Solvents such as nitrobenzene, trichlorobenzene, alcohols, glycols, pyridine, and aliphatic hydrocarbons are employed. By using substituted phthalic acids such as 4-chlorophthalic acid anhydride, 4-sulfophthalic acid anhydride, or 4-nitrophthalimide, phthalocyanines with inner substitution can be produced. The products can often be purified by sublimation in vacuo at 300-400 °C. Soluble Pc s can be purified by recrystallization. 

The catalytic oxidation of benzene to maleic anhydride in a fluid bed reactor has been investigated by Kizer, Chavarie, Laguerie and Cassimatis (9). Their reactor had an inner diameter of 18 cm. Shallow beds of catalyst with bed heights less then 10 cm were used with reaction temperatures between 420 and 460 °C. The catalyst was silica supported VjOj. 

Figure 4.9 Carbonylation of methyl acetate to acetic anhydride. The right-hand-side cycle is the same as in 4.1 and 4.2. The big cycle on the left is similar to the organic cycle of 4.2, where acetic acid and methyl acetate substitute for water and methanol. The small inner cycle on the left is the dominant product-forming pathway.

Apparently an inner anhydride is formed between the carbinol hydroxyl and the sulfo group, and this causes the stability toward soda and caustic alkali. This assumption appears probable because dyes of the type below are entirely insoluble ... 

The inner etherification induced in the sorbitol and D-mannitol structures during polyester formation, made a study of their inner ethers or anhydrides a matter of practical significance. A new monoanhydride of sorbitol was described (21) and designated arlitan (from the initials of the Atlas Research Laboratory). Identification as 1,4-anhydro-D-glucitol was made by comparison of its sirupy tetramethyl ether with that obtained by acid anhydrization of Irvine s 2,3,5,6-tetramethyl-D-glu-citoP by oxidation of the tetramethyl ether to dimethyl-L-threaric acid [0-dimethyl-L-((iea tartaric acid] and identification as the crystalline diamide and by its behavior on oxidation with lead tetraacetate. ... 

Diphenylpyrazine (1, R = R = Hi, R = R = H) was the second pyrazine synthesized, and it was prepared by Staedel and Riigheimer (10) in 1876 by the action of ammonia on w-chloroacetophenone and was named isoindol. These authors postulated the first structure for a pyrazine as an inner anhydride (2) of an amino ketone. 

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