Hydrolysis with phosphoric acid

Trichloroacetyl fluoride, 45, 6 2-(Trichloromethyl)bicyclo[3.3.0]octane, from reaction of chloroform and cib,o i-l,5-cyclooctadiene, 47,10 hydrolysis with phosphoric acid to c.ro-m-bicyclo[3.3.0]octane-2-carboxylic acid, 47, 11 1,1,3-Trichloro- -nonane, 46,104 Tricyclo[2.2.1,02 6]heptan-3-ol, 46,... 

This reaction was initially reported by Franchimont in 1872. It is a condensation of two a-bromocarboxylic acids in absolute alcohol in the presence of sodium cyanide to give 1,2-dicarboxylic acids after hydrolysis and decarboxylation. In the case of a-bromoketones, 1,4-diketones are produced similarly after hydrolysis with phosphoric acid. It was found that the bulky group at the ester end prevents condensation, as in the case of phenyl and naphthyl esters. Although the substituent at j0-position does not prevent such condensation, it reduces the overall yield. In addition, a compound with two ester groups at proper position will form cyclic diacid under such reaction conditions and cyclobutane, " cyclopentane and cyclohexane dicarboxylic acid have been prepared in such a way. In the case of l,4-dibromo-l,4-dibenzoylbutane, a derivative of cyclopentanone is produced after acidic hydrolysis. It should be pointed out that other common solvents—including acetone, ether, and acetonitrile- are not good for this reaction. ... 

Phosphorolysis is a term sometimes used to describe the transfer of group (11.33b), since the reaction is analogons to that of hydrolysis with phosphoric acid replacing water (11.40). A process of this kind occnrs in other reactions below, such as the breakdown of glycogen (11.58) and the degradation of polynncleotides (11.122). 

The lignin is obtained from the biomass by a two-step hydrolysis with phosphoric acid, followed by an enzymatic hydrolysis in order to remove the polysaccharides. The nitrogen in the lignin can be increased by a Mannich reaction, thus increasing the ionic capacity. It has been foimd that cationic lignin is suitable to catch chloride ions in concrete (49). 

Polyamide 6 depolymerisation was performed using microwaves as the energy source for the acid catalysed hydrolysis, with phosphoric acid as the catalyst. The product mixture was analysed by chromatographic and spectroscopic methods. 19 refs. 

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). 

Aminotrimethanephosphonic acid is formed from formamide, acetamide, urea, or alkanenitriles with phosphorous acid [296]. By reaction of monoalkyl phosphite or P406 with glacial acetic acid or the corresponding anhydride ethane-1 -hydroxy-1,1-diphosphonic acid is formed after hydrolysis [297,298]. P406 can be obtained from P4 and 02 in a high yield of 85-90% [299]. 

An alternative sequence utilized 2-oxazolidone, which was readily synthesized from urea and ethanolamine, as the glycine equivalent. Subsequent treatment with phosphorous acid and formaldehyde produced iV-phosphonomethyl-2-oxazolidone 12 (16). Upon hydrolysis, and loss of CO2,12 provided the related derivative, iV-phosphonomethylethanolamine 13, which was oxidized at high temperature with a variety of metal catalysts including cadmium oxide (16) or Raney copper (17) to give GLYH3, after acidification. A similar oxidation route has also been reported starting from iV-phosphonomethy 1-morpholine (18). 

Several 1 -phosphates of deoxyfluoro sugars were prepared, and their acid-catalyzed hydrolysis was studied. 2-Deoxy-2-fluoro- (580), 3-deoxy-3-fluoro- (582), 4-deoxy-4-fluoro- (583), and 6-deoxy-6-fluoro-a-D-gluco-pyranosyl phosphates (584) were prepared by treatment of the corresponding per-( -acetylated )9-D-glucopyranoses with phosphoric acid [the p anomer (581) of 580 was prepared by a different method]. The first and second ionization constants (pA a, and pA a2) of these compounds were determined potentiometrically, as well as by the F-n.m.r. chemical shifts at a series of pH values, and then the rate constants of hydrolysis for neutral (B) and monoanion (C) were decided. The first-order rate-constants (k) for 580-584 and a-D-glucopyranosyl phosphate (in Af HCIO4,25 °) were 0.068, 0.175, 0.480, 0.270, 1.12, and 4.10 (all as x lOVs), respectively. The rate... 

Partial hydrolysis reactions lead to a monoalkyl phosphite, but complete hydrolysis gives phosphorous acid. The hydrogen atom bound to phosphorus can also be replaced by reaction with sodium, showing that the hydrogen atom has slight acidity. 

Acid phosphatase (acid phosphomonoesterase, EC 3.1.3.2) also catalyzes the hydrolysis of phosphoric acid monoesters but with an acidic pH optimum. It has broad specificity and catalyzes transphosphorylations. Acid phosphatases are a quite heterogeneous group with monomeric, dimeric, larger glycoprotein, and membrane-bound forms. Acid phosphatase activity is present in the heart, liver, bone, prostate, and seminal fluid. Prostate carcinomas produce large quantities of acid phosphatase, and the enzyme is, therefore, used as a biomarker [141]. 

In whole blood, phosphatase activity is associated primarily with red blood cells, but it is recognized that blood has a low phosphatase activity compared to other tissues such as the kidney, brain, liver, lung, and heart ([87] [88] and refs. cit. therein). Thus, studies with blood preparations should underestimate the in vivo rate of hydrolysis of phosphoric acid esters, a point of significance in the development of phosphate prodrugs. 

Condensation of the pyrrolidine enamine of cyclohexanone with l,l-dicyano-2,2-dimethylcyclopropane proceeds smoothly in refluxing dry xylene and gives the expected adduct in 76% yield. Recrystallisation of the adduct from 95% ethanol, however, gave a 91% yield of a product which no longer contained the pyrrolidine group but whose spectral data clearly showed the presence of a ketone group and an enaminonitrile function. Hydrolysis of this latter product with phosphoric acid/acetic acid gave 5-(2-oxo-4,4-dimethylcyclopentyl)pentanoic acid in 83% yield. 

Conversion of (107) into the dimethyl acetal (108) with trimethyl orthoformate and Rexyn 101, followed by pyrolytic elimination in refluxing o-xylene, gave (109). Treatment of (109) with n-butyl-lithium and C02 in THF, followed by hydrolysis, afforded the keto-acid (110). Reduction of (110) with borohydride, followed by dehydration with phosphoric acid and esterification, gave (111). 

Weber [61,62] has developed in the context of prebiotic chemistry an original pathway for a-aminothioester synthesis [180], which can start from hydroxyaldehydes 30 intermediates in the formose reaction (a likely prebiotic pathway to carbohydrates). Obviously, thioesters themselves are not observed as products because of their fast hydrolysis in the medium, but they could be converted into peptide bonds in the presence of amino acids or peptide free amino groups, and into mixed anhydride with phosphoric acid in the presence of inorganic phosphate. The reaction involves two key-steps the condensation of ammonia and of the mercaptan on a-keto aldehyde 31... 

Production of alumina aquosols from alumina has been well researched in sol-gel science [19]. Yoldas [20] was the first one to show that monolithic alumina gels could be formed by hydrolysis and condensation of aluminum alkoxide. As discussed in Chapter 5, formation of aquosols and their gel is an intermediate step in the formation of chemically bonded phosphate ceramics. Condensation of the hydrated alumina sols by reaction with phosphoric acid to form A1(H2P04)3-H20 gel is the first step toward synthesis of a berlinite-bonded alumina ceramic. When this gel is heated to 150°C, this gel reacts with additional alumina and releases water, and crystalline berlinite is produced. This Chapter... 

Figure 8. Homogeneous hydrolysis in phosphoric acid, illustrating enhanced rate for wood pulp (MS40, 50) compared to that of cotton samples (MS51, 91). (Reproduced with permission from Ref. 2. Copyright 1971 Wiley.)...

The preparation can be carried out with phosphoric acid in place of sulfuric acid, but it is customary instead to prepare hydrogen bromide in the laboratory by the hydrolysis of phosphorus tribromide, PBrg. The reaction can be carried out by mixing red... 

As some fractions of the limit dextrins produced by the common amylases have a much higher phosphorus content than starch, the author assumed that the substitution with phosphoric acid is one of the anomalies postulated as the cause of the limit dextrin formation. That the phosphoric acid acts in this way is evident from the investigations of Posternak, who isolated a tetraose phosphate from a mixture of limit dextrins. On acid hydrolysis this gave D-glucose 6-phosphate. 

Fluidization with phosphoric acid is not recommended because darkening of the product and hydrolysis may occur. Degumming with acetic anhydride results in fluidized lecithins possibly because PE is acetylated by the reagent. Nonedible lecithins may be fluidized by the addition of acidulated and dried soapstock. 

Complete hydrolysis (with mineral acid) of each of these nucleotides gives the appropriate purine or pyrimidine base, phosphoric acid, and a pentose or furfural (its degradation product). Since the nucleotides... 

Hydrolysis gives phosphorous acid and the halogen hydracid the ease of hydrolysis increases with molecular weight ... 

This compound (4) was prepared both by Holker132, and Buchi et al.55), in connection with studies done to help elaborate the structures of the B and G series of toxins. Condensation of phloroglucinol dimethyl ether (39)133 with diethyl j3-oxoadipate (sulfuric acid) gave the coumarin (6), after a hydrolysis-cyclization (phosphoric acid) sequence. Compound (4) was then able to be obtained by catalytic hydrogenation of(6). 

For tricresyl phosphate to be effective, oxygen, water and other polar impurities are important for the formation of reaction films. The beneficial influence of water and oxygen indicates that the formation of the reaction film is preceded by the hydrolysis of ester and the release of phosphoric acid which Anally reacts with the surface oxide film. The importance of the polar impurities present in TCP has been demonstrated [26] the probable identity of the important impurity is lauryl acid phosphate, found to be 20 times as effective at wear protection compared to pure tricresyl phosphate. A conclusion is that the ester function of phosphoric acid is necessary only to ensure solubility of the product in oil. TCP can also give rise to anti-rust protection by hydrolysis to phosphoric acid. 

As noted (1, 132), an early procedure of Eliel and Doyle for the reduction of 4-t-butylcyclohexanone to cis-4-f-butylcyclohexanol used iridium trichloride supplied by Fisher. This reagent is no longer available and, in a newer procedure,1 iridium tetrachloride is used as catalyst in combination with trimethyl phosphite, which undergoes hydrolysis to phosphorous acid the actual reducing agent is probably... 

Functionalized five- to eight-membered dioxo-l,2-azaphosphacyclanes 129 were prepared by cyclization of dicarbocylic acid diamides and dinitriles with phosphorous acid and phosphorus halogenides followed by hydrolysis (Scheme 78) [173], Such cyclic aminophosphonic acids were suggested as efficient complexing agents for Ca2+ for reduction of aorta calcification (on the rat model) and as hardening retardants for gypsum, etc. 

USE Separation of Ce from other rare earths catalyst in hydrolysis of phosphoric acid esters mixture with ThfNOj) (1 99) formerly used in manuf incandescent mantles. 

Organophosphates Organophosphates are long-acting drugs they form an extremely stable phosphate complex with the enzyme after initial hydrolysis, the phosphoric acid residue is released over periods of days to weeks. 

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