Acetic anhydride acetate homologation

Thus, the overall acetaldehyde selectivity approaches 98%. The utility of methyl acetate as an alternative feedstock has been previously illustrated by the reported carbonylation to acetic anhydride ( ) and homologation ( ) to ethyl acetate via reaction with synthesis gas. 

Coumarin formation proceeds via an intramolecular attack by enol ester 9 on the ketone to give 10. Dehydration of 10 then affords coumarin 11. It has been observed that coumarins are favored when higher order homologs of acetic anhydride and their corresponding salts such as propionic anhydride/sodium propionate and butyric anhydride/ sodium butyrate are used. 

Sen and Kakaji synthesized a series of 4-butyrylnaphthocoumarins 48 from l-butyryl-2-naphthols 49 using acetic anhydride and two homolog anhydrides in excellent yields. They also showed that l-propionyl-2-naphthols and l-acetyl-2-naphthols could be converted to their corresponding coumarins using the same three anhydrides. However, l-acetyl-2-naphthol in the presence of acetic anhydride and sodium acetate gave a chromone not a coumarin. 

Reactions lla-e add up to Reaction 10. Reactions lla-b have been shown above to be catalyzed by Rh/CH3l. Reaction 11c, i.e. acid-catalysed pyrolysis of EDA to acetaldehyde and acetic anhydride, is well documented (9). Both reaction lid, hydrogenation of aldehyde, and Reaction lie, carbonylation of alcohols, are of course well known. The reaction sequence is in agreement with the fact that EDA and AH, especially in short-duration experiments, are detected as by-products. Acetaldehyde is also observed in small quantities, but no ethanol is found. Possibly, Reactions lid and He occur concertedly. We have separately demonstrated that both EDA and AH are suitable feeds to produce propionic acid under homologation reactions conditions. We thus demonstrated... 

For both reactions a RhCl3/CH3l/TPO catalyst in acetic acid as reaction solvent affords propionic acid in more than 80 % yield according to the respective stoichiometries of Equations 12 and 13. Although acetic acid is present in excess in the reaction medium, it does not participate in the homologation as reactant. Only traces of propionic acid are produced in the absence of methyl acetate, ethyli-dene diacetate or acetic anhydride under our reaction conditions. Homologation of carboxylic acids has been reported by Knifton (10) to require more severe reaction conditions (220 °C, > 100 bar). 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

Oxazolin-5-ones have also proven to be important intermediates in the homologation of carboxylic acids (71AG(E)655). The IV-acyl-DL-valine derivative (402), prepared from the acid chloride of the carboxylic acid and DL-valine by the Schotten-Baumann procedure, was treated with excess acetic anhydride to afford (403). Reaction of (403) with acrylonitrile and triethylamine led to (404) in good yield. Hydrolysis of (404) with dilute alkali or acid gave the y-keto nitrile or y-keto acid (Scheme 89). 

Co(III)] complexes. For example, the coupling of 3-halocholestanes (333) and Michael acceptors affords epimeric mixtures of the 3-homologated steroids (334). The electrochemical nucleophilic acylation of a, 3-unsaturated aldehydes, a,3-unsaturated ketones and a,(3-unsaturated nitriles with acyl anhydrides affords adducts (335) in moderate yields.226a-b Similarly, the reduction of N-methyloxazolinium salts (336) affords die A, O-acetal intermediates (337) which are readily hydrolyzed (Scheme 102).226c... 

In the first step of this one-carbon homologation, the diazomethane carbon is acylated by an acid chloride or mixed anhydride, to give an a-diazoketone. The excess diazomethane can be destroyed by addition of small amounts of acetic acid or vigourous stirring. Most a-diazoketones are stable and can be isolated and purified by column chromatography. 

In the future, there is no doubt that alcohols will play a major role not only as fuel components (70,71) but also as feed stocks for the syntheses of more complicated organic compounds (72). A great amount of research effort is presently directed to the economic conversion of CO and to methanol (73), and on homologation of methanol to higher alcohols (74). Conversion of synthesis gas from coal to acetic anhydride (75) through the intermediacy of methyl acetate (from methanol) will soon be a commercial reality. 

The method used depends upon the fact that although acetic acid and its homologs react with difficulty with bromine, the anhydrides and add bromides readily yield bromo substitution products. ... 

The mono- and poly-alkylated benzenes are treated using modifications of the above procedure. Monoalkylbenzenes are added to a preformed complex of acyl halides and aluminum chloride in carbon tetrachloride (Perrier modification). In this manner, the manipulation is easier, no tars are encountered, and the yields are improved (85-90%). The procedure shows no advantage, however, in the acylation of alkoxy- or chloro-aromatic compounds. The addition of benzoyl chloride to p-alkylbenzenes in the presence of aluminum chloride in cold carbon disulfide is a good procedure for making p-alkylbenzophenones (67-87%). The condensation of homologs of benzene with oxalyl chloride under similar conditions yields p,p -di alkylbenzophenones (30-55%). Polyalkylbenzenes have been acylated with acetic anhydride and aluminum chloride (2.1 1 molar ratio) in carbon disulfide in 54-80% yields. Ferric chloride catalyst has been used under similar conditions. Acetylation of p-cymene with acetyl chloride and aluminum chloride in carbon disulfide yields 2-methyl-5-isopropylaceto-phenone (55%). ... 

Acetic acid is quantitatively converted to acetic anhydride by reaction with ketene. Mixed anhydrides are formed when homologs of acetic acid or aromatic acids are used in the reaction. Upon distillation at atmospheric pressure, the mixed anhydrides disproportionate into acetic anhydride and the symmetrical anhydride corresponding to the carboxylic acid. Yields of propionic, n-butyric, and w-caproic anhydrides prepared by this method are in the range of 80% to 87%. ... 

Some supporting facts for the participation of acetic anhydride may be derived from the interaction of I—or III—with weakly nucleophilic water. Interestingly, not only is the homolog of II, namely, X, produced in this fashion, but two additional components, XI and XII, have been shown to coexist with it as well. If the formation and/or survival of a-aminohydrin XI is surprising, the anti-Bredt structure XII, which is in fact the hydroxide salt of intermediate... 

In order to study possible side reactions which may reduce the yield in the Woodward method of annulation of azetidin-2-ones (Scheme 31) similar reactions of ylides (214), which do not contain groups capable of conversion to carbonyl by DMSO-acetic anhydride treatment, have been investigated. 30 A range of products, e.g. (215) and (216), were obtained. A mild, four-carbon homologation of the 4-formyl-substituted azetidinone (217) involving reaction with the phosphonium ylide (218) has been used to synthesize (219), a useful intermediate in the synthesis of carbacephem antibiotics. 3 ... 

Amino-5-aminomethyl-3-benzyltriazole acetate, when heated with triethyl orthoformate, produced lV,AI -bis- 5-aminomethyl)-3-benzyltriazol-5-ylformamidine (30) (100°C, 1 hr, 90%). The same starting material, but as the free base, heated with triethyl orthoformate and acetic anhydride, gave 5-acetamidomethyl-3-benzyl-4-ethoxymethylenaminotriazole (31a) (100°C, 1 hr, 80%) triethyl orthoacetate similarly made the homolog 31b (50%) [76JCS(P1)291]. 

Barbier-Wieland degradation. Stepwise carboxylic acid degradation of aliphatic acids (particularly in sterol side chains) to the next lower homo log. The ester is converted to a tertiary alcohol that is dehydrated with acetic anhydride, and the olefin oxidized with chromic acid to a lower homologous carboxylic acid. 

Carboxamide and ureido groups react on heating the compound in a mixture of dioxane and acetic anhydride the product is a homologous purinedione. 

However, 70 hr at 200°C was necessary to convert 2-aminobenzonitrile in formic acid to quinazolin-4-one.193 Acetic anhydride formed the 2-methyl homolog under similar conditions, but higher anhydrides reacted very little.194... 

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