Formic acid anhydride

In the reaction of formic acid 494 with DCC, the very unstable formic acid anhydride 495 can be obtained." ... 

Derivatives of 7-(benzylamino)[l,2,5]thiadiazolo[3,4-tf]pyrimidine with formic acid anhydride give the corresponding formyl analogs which, following reductive desulfurization with Raney nickel, undergo cyclization through the formyl moiety, yielding 9-benzyladenines, e.g. 6. ... 

Chlorosulfonyl isocyanate was introduced by Olah for the preparation of acid anhydrides. Under very mild conditions it is even possible to obtain formic acid anhydride. This method has been applied successfully to other examples (equation 38). ... 

The lifetime of glycidaldehyde against reaction with OH is estimated to be about 7 h for daytime [OH] 2.5 x 10 molecule cm . Maet al. (1998) also showed that photolysis is likely an important loss process, with an estimated lifetime of 4 h for a noontime, midlatitude summer day see section lX-C-2 and table IX-M-1. These workers also studied the OH-initiated oxidation of glycidaldehyde in the absence of NOx, and identified initial yields of formic acid anhydride ( 45%), formic acid ( 20%), formaldehyde ( 25%), and CO2 ( 20%), as the major products. The main channel for OH reaction is likely via abstraction of the aldehydic H-atom, which would be expected to lead (in part) to formation of CO2 and the oxiranoxy radical, whose chemistry is outlined in figure Ill-E-2. 

O -ester rearrangement (Tuazon et al., 1998b) to give HC(0)0H and HCO radicals and reaction with O2 to give HC(0)0C(0)H (formic acid anhydride). 

Pungent odour. Formic acid, acetic acid, acetyl chloride, acetic anhydride, benzoyl chloride, benzyl chloride, pyridine. Benzoquinone (when warmed with water). 

Boric anhydride. This is a powerful and efficient desiccant and will absorb up to about 25 per cent, of its weight of water. It is useful for drying formic acid. 

The desired pyridylamine was obtained in 69 % overall yield by monomethylation of 2-(aminomethyl)pyridine following a literature procedure (Scheme 4.14). First amine 4.48 was converted into formamide 4.49, through reaction with the in situ prepared mixed anhydride of acetic acid and formic acid. Reduction of 4.49 with borane dimethyl sulfide complex produced diamine 4.50. This compound could be used successfully in the Mannich reaction with 4.39, affording crude 4.51 in 92 % yield (Scheme 4.15). Analogous to 4.44, 4.51 also coordinates to copper(II) in water, as indicated by a shift of the UV-absorption maximum from 296 nm to 308 nm. 

Acetic acid, fp 16.635°C ((1), bp 117.87°C at 101.3 kPa (2), is a clear, colorless Hquid. Water is the chief impurity in acetic acid although other materials such as acetaldehyde, acetic anhydride, formic acid, biacetyl, methyl acetate, ethyl acetoacetate, iron, and mercury are also sometimes found. Water significantly lowers the freezing point of glacial acetic acid as do acetic anhydride and methyl acetate (3). The presence of acetaldehyde [75-07-0] or formic acid [64-18-6] is commonly revealed by permanganate tests biacetyl [431-03-8] and iron are indicated by color. Ethyl acetoacetate [141-97-9] may cause slight color in acetic acid and is often mistaken for formic acid because it reduces mercuric chloride to calomel. Traces of mercury provoke catastrophic corrosion of aluminum metal, often employed in shipping the acid. 

The anhydride of formic acid has not been isolated, but mixed anhydrides are known, and, with acetic acid, the latter have utifity as formylating agents (22). The only known formyl haUde is the fluoride, which has a boiling poiat of —29° C. 

Aldehyde Synthesis. Formylation would be expected to take place when formyl chloride or formic anhydride reacts with an aromatic compound ia the presence of aluminum chloride or other Friedel-Crafts catalysts. However, the acid chloride and anhydride of formic acid are both too unstable to be of preparative iaterest. 

Oxidation. Maleic and fumaric acids are oxidized in aqueous solution by ozone [10028-15-6] (qv) (85). Products of the reaction include glyoxyhc acid [298-12-4], oxalic acid [144-62-7], and formic acid [64-18-6], Catalytic oxidation of aqueous maleic acid occurs with hydrogen peroxide [7722-84-1] in the presence of sodium tungstate(VI) [13472-45-2] (86) and sodium molybdate(VI) [7631-95-0] (87). Both catalyst systems avoid formation of tartaric acid [133-37-9] and produce i j -epoxysuccinic acid [16533-72-5] at pH values above 5. The reaction of maleic anhydride and hydrogen peroxide in an inert solvent (methylene chloride [75-09-2]) gives permaleic acid [4565-24-6], HOOC—CH=CH—CO H (88) which is useful in Baeyer-ViUiger reactions. Both maleate and fumarate [142-42-7] are hydroxylated to tartaric acid using an osmium tetroxide [20816-12-0]/io 2LX.e [15454-31 -6] catalyst system (89). 

In principle, aspartame is produced through the coupling of two amino acid moieties. One moiety consists of T.-phenylalanine methyl ester hydrochloride (2) made by treating the amino acid ia methanol and hydrochloric acid the other is aspartic acid anhydride hydrochloride or formic acid salt. The coupling reaction generates two positional isomers, a and p. 

The alkanoic acids, with the exception of formic acid, undergo typical reactions of the carboxyl group. Formic acid has reducing properties and does not form an acid chloride or an anhydride. The hydrocarbon chain of alkanoic acids undergoes the usual reactions of hydrocarbons except that the carboxyl group exerts considerable influence on the site and ease of reaction. The alkenoic acids in which the double bond is not conjugated with the carboxyl group show typical reactions of internal olefins. All three types of reactions are industrially important. 

Acetals. Acetal resins (qv) are polymers of formaldehyde and are usually called polyoxymethylene [9002-81-7]. Acetal homopolymer was developed at Du Pont (8). The commercial development of acetal resins required a pure monomer. The monomer is rigorously purified to remove water, formic acid, metals, and methanol, which act as chain-transfer or reaction-terminating agents. The purified formaldehyde is polymerized to form the acetal homopolymer the polymer end groups are stabilized by reaction with acetic anhydride to form acetate end groups (9). 

Hydrazinopyridazines are easily formylated with formic acid or ethyl formate and acety-lated with acetic anhydride. A-Pyridazinylthiosemicarbazides are obtained from thiocyanates or alkyl- and aryl-isothiocyanates. Hydrazinopyridazines condense with aliphatic and aromatic aldehydes and ketones to give hydrazones. 

Acid moieties include formic acid itself, formates and orthoesters, formamide, DMF dimethyl acetal and ethyl diethoxyacetate, acids, acid chlorides and anhydrides, the last including a rare [3,4-oxalate esters, 2-acyl or 2-ethoxycar-bonyl derivatives e.g. 180) are formed. 

Paint and varnish manufacturing Resin manufacturing closed reaction vessel Varnish cooldng-open or closed vessels Solvent thinning Acrolein, other aldehydes and fatty acids (odors), phthalic anhydride (sublimed) Ketones, fatty acids, formic acids, acetic acid, glycerine, acrolein, other aldehydes, phenols and terpenes from tall oils, hydrogen sulfide, alkyl sulfide, butyl mercaptan, and thiofen (odors) Olefins, branched-chain aromatics and ketones (odors), solvents Exhaust systems with scrubbers and fume burners Exhaust system with scrubbers and fume burners close-fitting hoods required for open kettles Exhaust system with fume burners... 

Boric anhydride. (Prepared by melting boric acid in an air oven at a high temperature, cooling in a desiccator, and powdering.) Mainly used for drying formic acid. 

Anhydrides have also been employed (31). The mixed anhydride of acetic and formic acid reacts with the enamine (113) to give a 50% yield of 2-hydroxymethylene cyclohexanone (119). 

However, though N2O can be made in this way it is not to be regarded as the anhydride of hyponitrous acid since H2N2O2 is not formed when N2O is dissolved in H2O (a similar relation exists between CO and formic acid). 

Several examples exist for the conversion of 5-aminothiazoles into the corresponding thiazolopyrimidines. Shaw and Butler report the formation of aminothiazole thiocarboxyamide 27 from the thioamide 26 and carbon disulphide using Cook and Heilbron s procedure. Methylation of 27 gave carboxythioimidate 28 which then reacted with sodium hydroxide to give amino-nitrile 29, and with formic acid and acetic anhydride to give the thiazolopyrimidine 30. 

In an interesting analogy to the penicillin series, acylation of 7-ACA with the phenylglycine moiety affords a compound with oral activity. Thus, phenylglycine is first protected as the carbo tertiary butyloxy derivative (45). Reaction of this with isobutyloxy chloroformate affords the mixed anhydride (46). Condensation of that with 7-ACA gives the intermediate, 47. Treatment with either trifluoroacetic or formic acid provides the free amine cephaloglycin (48). ... 

Schimmel Co. attempted to acetylise the alcohol by means of acetic anhydride, but the reaction product only showed 5 per cent, of ester, which was not submitted to further examination. The bulk of the alcohol had been converted into a hydrocarbon, with loss of water. Ninety per cent, formic acid is most suitable for splitting off water. Gne hundred grams of the sesquiterpene alcohol were heated to boiling-point with three times the quantity of formic acid, well shaken, and, after cooling, mixed with water. The layer of oil removed from the liquid was freed fi-om resinous impurities by steam-distillation, and then fractionated at atmo.spheric pressure. It was then found to consist of a mixture of dextro-rotatory and laevo-rotatory hydrocarbons. By repeated fractional distillation, partly in vacuo, partly at ordinary pressure, it was possible to separate two isomeric sesquiterpenes, which, after treatment with aqueous alkali, and distillation over metallic sodium, showed the following physical constants —... 

Acetylation of kasuganobiosamine with acetic anhydride in methanol gave N,N -diacetylkasuganobiosamine which contained no titrable group and reduced 6.6 moles of sodium periodate, affording 4.7 moles of formic acid, 0.5 mole of carbon dioxide, and a reducing substance —i.e., N,N -diacetylkasugamine. 

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