Carbon dioxide, acetate synthesis from

Another B12 coenzyme-dependent dehydrase converts glycerol to 3-hydroxypropionaldehyde. A B12-dependent ethanolamine deaminase catalyzes the irreversible conversion of ethanolamine to acetaldehyde and ammonia. A corrinoid protein participates in methyl transfer reactions and methane formation by bacteria producing methane. Corrinoid proteins are also involved in acetate synthesis from carbon dioxide. 

H.A. Barker, S. Ruben and J.V. Beck, Radioactive Carbon as an Indicator of Carbon Dioxide Reduction. IV. The Synthesis of Acetic Acid from Carbon Dioxide by Clostridium Acidi-Urici, Proceedings of the National Academy of Sciences 26, 477-482, 1940. 

Synthesis from Carbon Dioxide. Acetic acid synthesis from methane and carbon dioxide was reported under the conditions similar to those for methane carbonylation (eqs. (38-40)) (55,60,63). The reaction shown in equation (39) is fascinating because it uses H2O2 as the oxidant and water as the solvent. 

Acetic acid can be formed from only methane and CO2. However, equations (38—40) all require excess oxidants and the fate of the oxygen atom is unclear. Acetic acid formation only from methane should be considered. In the vanadium-catalyzed acetic acid synthesis from carbon dioxide using K2S2O8 in CF3CO2H, the reaction is independent of the CO2 pressure and CF3H is formed (63). A radical mechanism is probably involved. 

Sakakura T, Saito Y, Choi J-C, Masuda T, Sako T, Oriyama T (1999) Metal-catalyzed carbonate synthesis from carbon dioxide and acetals. J Org Chem 64 4506-4508... 

The reactions catalyzed by B12 may be grouped into two classes those catalyzed by methylcobalamin and those catalyzed by cofactor B,2. The former reactions include formation of methionine from homocysteine, methanogenesis (formation of methylmercury is an important side reaction), and synthesis of acetate from carbon dioxide (82). The latter reactions include the ribonucleotide reductase reaction and a variety of isomerization reactions (82). Since dehydration and deamination have been studied quite extensively and very possibly proceed via [Pg.257]

The final acetate production is a result of ATP synthesis. Acetate is excreted from these organisms and used by Group II sulfate reducers. However, certain groups of organisms can oxidize some of these fermentative products to carbon dioxide, provided acetate is excreted from these organisms. This group is known as complete oxidizers. The acetate oxidation to carbon dioxide involves the TCA cycle, with a series of oxidation-reduction reactions involving electrons. 

To illustrate the specific operations involved, the scheme below shows the first steps and the final detachment reaction of a peptide synthesis starting from the carboxyl terminal. N-Boc-glycine is attached to chloromethylated styrene-divinylbenzene copolymer resin. This polymer swells in organic solvents but is completely insoluble. ) Treatment with HCl in acetic acid removes the fert-butoxycarbonyl (Boc) group as isobutene and carbon dioxide. The resulting amine hydrochloride is neutralized with triethylamine in DMF. 

In 1897, Reissert reported the synthesis of a variety of substituted indoles from o-nitrotoluene derivatives. Condensation of o-nitrotoluene (5) with diethyl oxalate (2) in the presense of sodium ethoxide afforded ethyl o-nitrophenylpyruvate (6). After hydrolysis of the ester, the free acid, o-nitrophenylpyruvic acid (7), was reduced with zinc in acetic acid to the intermediate, o-aminophenylpyruvic acid (8), which underwent cyclization with loss of water under the conditions of reduction to furnish the indole-2-carboxylic acid (9). When the indole-2-carboxylic acid (9) was heated above its melting point, carbon dioxide was evolved with concomitant formation of the indole (10). 

Still another possibility in the base-catalyzed reactions of carbonyl compounds is alkylation or similar reaction at the oxygen atom. This is the predominant reaction of phenoxide ion, of course, but for enolates with less resonance stabilization it is exceptional and requires special conditions. Even phenolates react at carbon when the reagent is carbon dioxide, but this may be due merely to the instability of the alternative carbonic half ester. The association of enolate ions with a proton is evidently not very different from the association with metallic cations. Although the equilibrium mixture is about 92 % ketone, the sodium derivative of acetoacetic ester reacts with acetic acid in cold petroleum ether to give the enol. The Perkin ring closure reaction, which depends on C-alkylation, gives the alternative O-alkylation only when it is applied to the synthesis of a four membered ring ... 

As we learned in Chapters 3 and 4, many inorganic compounds, not just ammonia, are derived from synthesis gas, made from methane by steam-reforming. In the top 50 this would include carbon dioxide, ammonia, nitric acid, ammonium nitrate, and urea. No further mention need be made of these important processes. We discussed MTBE in Chapter 7, Section 4, and Chapter 10, Section 9, since it is an important gasoline additive and C4 derivative. In Chapter 10, Section 6, we presented -butyraldehyde, made by the 0x0 process with propylene and synthesis gas, which is made from methane. In Chapter 11, Section 8, we discussed dimethyl terephthalate. Review these pertinent sections. That leaves only two chemicals, methanol and formaldehyde, as derivatives of methane that have not been discussed. We will take up the carbonylation of methanol to acetic acid, now the most important process for making this acid. Vinyl acetate is made from acetic... 

Numerous methods for the synthesis of salicyl alcohol exist. These involve the reduction of salicylaldehyde or of salicylic acid and its derivatives. The alcohol can be prepared in almost theoretical yield by the reduction of salicylaldehyde with sodium amalgam, sodium borohydride, or lithium aluminum hydride by catalytic hydrogenation over platinum black or Raney nickel or by hydrogenation over platinum and ferrous chloride in alcohol. The electrolytic reduction of salicylaldehyde in sodium bicarbonate solution at a mercury cathode with carbon dioxide passed into the mixture also yields saligenin. It is formed by the electrolytic reduction at lead electrodes of salicylic acids in aqueous alcoholic solution or sodium salicylate in the presence of boric acid and sodium sulfate. Salicylamide in aqueous alcohol solution acidified with acetic acid is reduced to salicyl alcohol by sodium amalgam in 63% yield. Salicyl alcohol forms along with -hydroxybenzyl alcohol by the action of formaldehyde on phenol in the presence of sodium hydroxide or calcium oxide. High yields of salicyl alcohol from phenol and formaldehyde in the presence of a molar equivalent of ether additives have been reported (60). Phenyl metaborate prepared from phenol and boric acid yields salicyl alcohol after treatment with formaldehyde and hydrolysis (61). 

Huisgen and coworkers have also described the cycloaddition behavior of the munchnones , unstable mesoionic A2-oxazolium 5-oxides with azomethine ylide character.166 Their reactions closely parallel those of the related sydnones. These mesoionic dipoles are readily prepared by cyclodehydration of N-acyl amino acids (216) with reagents such as acetic anhydride. The reaction of munchnones with alkynic dipolarophiles constitutes a pyrrole synthesis of broad scope.158-160 1,3-Dipolar cycloaddition of alkynes to the A2-oxazolium 5-oxide (217), followed by cycloreversion of carbon dioxide from the initially formed adduct (218), gives pyrrole derivative (219 Scheme 51) in good yield. Cycloaddition studies of munchnones with other dipolarophiles have resulted in practical, unique syntheses of numerous functionalized monocyclic and ring-annulated heterocycles.167-169... 

We discussed, in the Introduction, an attractive but nevertheless totally unrealistic route to the synthesis of acetic acid from methane and carbon dioxide ... 

The four-step synthesis of acetic acid shown above is carried out in such a way that all the chosen reactions lead to the exclusive, or at least highly predominant, formation of one product. This is ensured both by the nature of the reagents and the reaction conditions used. In turn, the proper choice of the conditions optimal for every step is possible because the synthesis is carried out in a stepwise fashion. It would be an absolutely hopeless adventure even to attempt to elaborate conditions that would enable one to achieve the synthesis of acetic acid in one flask from a simple mixture all of the required components (methane, carbon dioxide, bromine, and magnesium). 

In plant systems, de novo synthesis occurs in the plastid and results mainly in the conversion of acetate to palmitate. All 16 carbon atoms in palmitic acid are derived from acetate— half from the methyl carbon and half from the acyl carbon. Two of the carbon atoms (C-15 and C-16) come directly from acetate, and the other 14 come from acetate via the more reactive malonate. Production of malonate requires the incorporation of an additional carbon atom into the acetyl group. This is supplied as bicarbonate, and this same carbon atom is subsequently lost as carbon dioxide. The acyl groups are attached to co-enzyme A (CoASH) during part of the cycle and to acyl carrier protein (ACPSH) during another part. The abbreviated symbols used for these co-enzymes emphasize the thiol groups (SH) to which the acyl chains are attached. 

From Acetaldehyde and Malonic Acid.—Another synthesis proves the constitution of crotonic acid as A2-butenoic acid. A di-basic acid known as malonic acid has the constitution of di-carhoxy methane HOOC—CH2—COOH. When this acid is heated with acetaldehyde (paraldehyde) and glacial acetic acid condensation occurs as in the synthesis of crotonic aldehyde and in the Perkin-Fittig synthesis (p. 172). A dibasic acid is obtained which loses carbon dioxide and yields a mono-basic acid which is crotonic acid. 

From Acetic and Formic Acids.—A fourth method of synthesis from acetic and formic acid esters will be explained in detail in connection with the next acid. All of these syntheses prove the constitution of pyro-racemic acid as an a//>/fa-ketone acid as given. It may be considered as aceto formic acid which is in accord with the fourth method of synthesis. As an acid it forms all acid derivatives and as a ketone it undergoes the characteristic ketone reactions, e.g.y with phenyl hydrazine and hydroxyl amine. On heating to 150° with dilute sulphuric acid in a sealed tube it loses carbon dioxide and yields acet aldehyde. 

S3mthesis of Collidine.—The most important synthesis of pyridine homologues is that of collidine from which pyridine may be obtained by elimination of the methyl groups by oxidation and loss of carbon dioxide. When aldehyde ammonia is heated with aceto-acetic ester a derivative of a di-hydrogenated collidine is obtained, as follows ... 

The present studies confirm the earlier studies indicating the relatively great biosynthetic abilities of the methane bacteria and suggest that much of the cellular carbon compounds are probably synthesized from acetate and carbon dioxide. In view of the carbon dioxide and acetate requirements and the reductive carboxylation reactions shown to be involved in isoleucine synthesis in M. ruminantium (26) and the probability of similar carboxylation reactions in biosynthesis of isoleucine, alanine, and other amino acids in MOH, suggested by the studies on M. omelianskii (34), the operation of the pyruvate synthase reaction and some other reactions of the reductive carboxylic acid cycle (35, 36) as major pathways of biosynthesis of cellular materials in these bacteria is an attractive hypothesis. 

Other lipases have also been tested in supercritical carbon dioxide for ester synthesis. In this context, the synthesis of terpinyl acetate from a-terpineol and acetic anhydride in supercritical carbon dioxide (scCO ) was carried out using five different lipases as catalysts (Candida rugosa type Vll, Amano PS, Amano AP-6,... 

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