Anhydrid, acetic phosphoric

Thiele reaction Acetic anhydride. Acetic phosphoric anhydride. Boron trifluoride etherate. 

FIGURE 3.10 (a) Electrostatic repnlsion between adjacent partial positive charges (on carbon and phosphorns, respectively) is relieved upon hydrolysis of the anhydride bonds of acetic anhydride and phosphoric anhydrides. The predominant form of pyrophosphate at pH values between 6.7 and 9.4 is shown, (b) The competing resonances of acetic anhydride and the simnltaneons resonance forms of the hydrolysis product, acetate. 

Resonance stabilization in the products is best illustrated by the reactant anhydrides (Figure 3.10b). The unpaired electrons of the bridging oxygen atoms in acetic anhydride (and phosphoric anhydride) cannot participate in resonance structures with both electrophilic centers at once. This competing resonance situation is relieved in the product acetate or phosphate molecules. 

There are many methods for the preparation of ethane-1-hydroxy-1,1-diphosphonic acid including reacting phosphorus trichloride and acetic acid in the presence of tributylamine [106], phosphorus with acetic acid and oxygen [108], acetic anhydride with phosphorous acid and acetyl chloride [80,84-86,109,110], and acetic anhydride with phosphoric acid and acetic acid [111]. By another method ketene and phosphorous acid can be used [112], as shown in Eq. (68) ... 

Alcohols can also be acylated by mixed organic-inorganic anhydrides, such as acetic-phosphoric anhydride, MeCOOPO(OH)2 (see 10-35). ... 

The reaction of acetic anhydride with phosphoric acid will generate the same electrophile and offers the advantage that only the monoacyl produci results. Acylation of the first ring deactivates the second and the concentration of CH3C+=0 from the phosphoric ucid reaction is too small to produce the diacyl product. 

Acetic-phosphoric anhydride, ho-p-o cch. [1, 4, before Aceloacetyl fluoride],... 

Despite wide variations of synthesis conditions, the treatment of cellulose with dimethylphosphite, monomethylphosphite and phosphorous acid failed to yield phosphites containing only one type of phosphorus-containing groups. This difficulty was overcome by using phosphoric anhydrides as the esterifying reagents. The action of mixed anhydrides of phosphorous acids and acetic acid on cellulose has yielded cellulose esters with alkyl-(methyl-)phosphorous acid (73) ... 

Fuming nitric acid in the presence of acetic anhydride oxidizes iodine, producing the compound I(OCOCH3)3. On oxidation of iodine with concentrated nitric acid in the presence of acetic anhydride and phosphoric acid, the compound IP04 is obtained. No direct structural information is available for these compounds, but they are probably best regarded as covalent. Nevertheless, electrolytic dissociation can occur and when a saturated solution of I(OCOCH3)3 in acetic anhydride is electrolyzed the quantity of silver iodide formed at a silvered platinum gauze cathode is in... 

Cyclodehydration of the thioamide-derived structures was induced by treatment with an acetic anhydride and phosphoric acid mixture, hi the case of the mixture of 90 and 91, N-glucopyranosyl tetrahydrothioxopyridine 92 was obtained upon acidic treatment [123]. Under the same conditions, compound 93 evolved to N-glucopyranosyl thioxopyrroline 94. 

Acetyl phosphate, which can be synthesized from acetic anhydride and phosphoric acid [526], is a commonly used regeneration system in conjunction with acetate kinase [527]. It is modestly stable in aqueous solution and while its phosphoryl donor potential is lower than that of PEP, it is considerably cheaper. As for pymvate kinase, acetate kinase also can accept nucleoside phosphates other than adenosine, and it is inhibited by acetate. 

The Friedel-Crafts acylation of ferrocene, which was mentioned above, has been studied in considerable detail. Substitution can be effected under very mild conditions, for instance with acetic anhydride containing phosphoric add as catalyst, to give mono-acetylferrocene. With aluminium chloride as catalyst, good yields of either mono- or l,l -diacetylferrocene can be obtained according to the proportions of reagents taken. 

B3 the slow distillation of an aromatic carboxylic acid and acetic anhydride in the presence of a little phosphoric acid ... 

Place 150 g. of benzoic acid, 150 g. (139 ml.) of acetic anhydride and 0-2 ml. of syrupy phosphoric acid in a 500 ml. bolt-head flask. Fit the latter with a two-holed stopper carrying a dropping funnel and an efficient fractionating column (compare Fig. 7/7, 61, 1) it is advisable to lag the latter with asbestos cloth. Set up the flask in an oil bath or in a fusible metal bath. Distil the mixture very slowly and at such a rate that the temperature of the vapour at the head of the column does... 

It may be pointed out that dehydration of p hydroxy esters with fused potassium hydrogen sulphate, acetic anhydride, phosphoric oxide or with tliionyl chloride in benzeue solution leads to ap unsiiturated esters containing some PY-unsaturated ester the proportion of the latter depends not only upon the structure of the ester but also upon the dehydrating agent used. Elehydration occasionally occurs during the reaction itself or upon attempted distillation. 

The important chemical properties of acetyl chloride, CH COCl, were described ia the 1850s (10). Acetyl chloride was prepared by distilling a mixture of anhydrous sodium acetate [127-09-3J, C2H202Na, and phosphorous oxychloride [10025-87-3] POCl, and used it to interact with acetic acid yielding acetic anhydride. Acetyl chloride s violent reaction with water has been used to model Hquid-phase reactions. 

Jicyylic anhydride is formed by treatment of the acid with acetic anhydride or by reaction of acrylate salts with acryloyl chloride. Jicryloylchloride is made by reaction of acryhc acid with phosphorous oxychloride, or benzoyl or thionyl chloride. Neither the anhydride nor the acid chloride is of commercial interest. 

The synthesis of 2,4-dihydroxyacetophenone [89-84-9] (21) by acylation reactions of resorcinol has been extensively studied. The reaction is performed using acetic anhydride (104), acetyl chloride (105), or acetic acid (106). The esterification of resorcinol by acetic anhydride followed by the isomerization of the diacetate intermediate has also been described in the presence of zinc chloride (107). Alkylation of resorcinol can be carried out using ethers (108), olefins (109), or alcohols (110). The catalysts which are generally used include sulfuric acid, phosphoric and polyphosphoric acids, acidic resins, or aluminum and iron derivatives. 2-Chlororesorcinol [6201-65-1] (22) is obtained by a sulfonation—chloration—desulfonation technique (111). 1,2,4-Trihydroxybenzene [533-73-3] (23) is obtained by hydroxylation of resorcinol using hydrogen peroxide (112) or peracids (113). 

Reactions. Heating an aqueous solution of malonic acid above 70°C results in its decomposition to acetic acid and carbon dioxide. Malonic acid is a useful tool for synthesizing a-unsaturated carboxyUc acids because of its abiUty to undergo decarboxylation and condensation with aldehydes or ketones at the methylene group. Cinnamic acids are formed from the reaction of malonic acid and benzaldehyde derivatives (1). If aUphatic aldehydes are used acryhc acids result (2). Similarly this facile decarboxylation combined with the condensation with an activated double bond yields a-substituted acetic acid derivatives. For example, 4-thiazohdine acetic acids (2) are readily prepared from 2,5-dihydro-l,3-thiazoles (3). A further feature of malonic acid is that it does not form an anhydride when heated with phosphorous pentoxide [1314-56-3] but rather carbon suboxide [504-64-3] [0=C=C=0], a toxic gas that reacts with water to reform malonic acid. 

Many other polymerization processes have been patented, but only some of them appear to be developed or under development ia 1996. One large-scale process uses an acid montmorrillonite clay and acetic anhydride (209) another process uses strong perfiuorosulfonic acid reski catalysts (170,210). The polymerization product ia these processes is a poly(tetramethylene ether) with acetate end groups, which have to be removed by alkaline hydrolysis (211) or hydrogenolysis (212). If necessary, the product is then neutralized, eg, with phosphoric acid (213), and the salts removed by filtration. Instead of montmorrillonite clay, other acidic catalysts can be used, such as EuUer s earth or zeoHtes (214—216). 

Synthesis. Hydroxyhydroquiaone is not produced on a large scale, but many uses for it are being developed. The most convenient preparation of hydroxyhydroquiaone is the reaction of -benzoquiaone with acetic anhydride ia the preseace of sulfuric acid or phosphoric acid. The resultant triacetate (29) can be hydrolyzed to hydroxyhydroquiaone (86). 

Phenyl isothiocyanate has been prepared from thiocarbanilide by the action of phosphorus pentoxide, hydrochloric acid, iodine, phosphoric acid, acetic anhydride, and nitrous acid. It has also been prepared from ammonium phenyl dithiocarbamate by the action of ethyl chlorocarbonate, copper sulfate lead carbonate, lead nitrate, ferrous sulfate,and zinc sulfate. ... 

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