Acetylation with acetyl chloride

Acyl halides, both aliphatic and aromatic, react with the sodium derivative, but the product depends largely on the solvent used. Thus acetyl chloride reacts with the sodium derivative (E) suspended in ether to give mainly the C-derivative (t) and in pyridine solution to give chiefly the O-derivative (2). These isomeric compounds can be readily distinguished, because the C-derivative (1) can still by enolisation act as a weak acid and is therefore... 

N.B. In all these reactions acetyl chloride reacts with much greater vigour than the other compounds, and accordingly tests with this substance must be carried out toith extreme care. 

Most cellulose acetate is manufactured by a solution process, ie, the cellulose acetate dissolves as it is produced. The cellulose is acetylated with acetic anhydride acetic acid is the solvent and sulfuric acid the catalyst. The latter can be present at 10—15 wt % based on cellulose (high catalyst process) or at ca 7 wt % (low catalyst process). In the second most common process, the solvent process, methylene chloride replaces the acetic acid as solvent, and perchloric acid is frequentiy the catalyst. There is also a seldom used heterogeneous process that employs an organic solvent as the medium, and the cellulose acetate produced never dissolves. More detailed information on these processes can be found in Reference 28. 

Otherwise, the main reactions at the methylene group are the dialkylation with alkyl haUdes (77), the acetylation with acetyl chloride which yields acetylma1 ononitrile [1187-11-7] (78), the Knoevenagel condensation, as well as the condensation with triethyl orthoformate, gives... 

Cinnolin-3(2//)-one (7) is methylated with diazomethane or methyl sulfate to give 2-methylcinnolin-3(2H)-one. In a similar manner, benzylation with benzyl chloride, cyanoethylation with acrylonitrile in the presence of benzyltrimethylammonium hydroxide and glucosidation with tetra-O-acetyl-a-o-glucopyranosyl bromide in the presence of a base affords the corresponding 2-substituted cinnolin-3(2//)-ones. However, glucosidation of the silver salt of cinnolin-3(2//)-one produces the corresponding O-substituted compound. 

Quinoxaline mono-N-oxides are also available by a direct synthesis from n-nitroaniline derivatives. Condensation of acetyl chloride derivatives with o-nitroaniline followed by treatment with sodium ethoxide in ethanol yields the mono-N-oxides in good yields (Scheme 20) (64JCS2666). 

Triazoles are acylated with acyl halides, usually initially at the 1-position, but the acyl group may migrate to the 2-position on heating or on treatment with base. Thus acetylation with acetyl chloride often gives 1-acetyl derivatives, which rearrange to the 2-isomers above 120 °C (74AHCil6)33). 

To dehydrolaudanosoline chloride Robinson and Sugasawa, and independently Schopf and Thierfelder ascribe formula (VI), which makes it 2 3 11 12-tetrahydroxy-8-methyldibenzotetrahydropyrrocolinium chloride. The primary tetracetyl-derivative, m.p. 148°, is represented by (VII R = acetyl) and the second acetyl derivative, m.p. 215°, by (VII R = acetyl) with an ethylenic linkage between carbon atoms 15 and 16. Similarly, the initial tetramethoxy-derivative is to be represented by (VI) with the four hydroxyl groups replaced by methoxyl groups the primary product formed on heating, by loss of methyl chloride, will be represented by (VII R = OMe), and the second product, m.p. 201-3°, of the reaction will be represented by (VII R = OMe), with an ethylenic linkage between and C e-... 

Acetyl chloride, reaction with 2-acetamido-2-deoxy-D-glucose, 46, 1... 

Evaporate the sample to dryness with clean, dry nitrogen. Add 250 /jl of methanol and 50 fil of concentrated sulfuric acid. Heat at 60° for 45 min. Add 250 fil of distilled water and allow to cool. Then add 50 fil of chloroform or methylene chloride. Shake the mixture for 2 min. Remove the bottom layer with a syringe. Evaporate to dryness with clean, dry nitrogen. Acetylate with 50 ju.1 of three parts acetic anhydride and two parts pyridine for 30 min at 60°. Evaporate to dryness with clean, dry nitrogen. Dissolve the residue in 25 fi of ethyl acetate. 

Preparation of the acetate derivative Concentrate the aqueous mixture of saccharides to approximately 0.5 ml in a 20-50 ml container. Reduce the saccharides by adding 20 mg of sodium borohydride that has been dissolved carefully into 0.5 ml of water and let the reducing mixture stand at room temperature for at least 1 hour. Destroy the excess sodium borohydride by adding acetic acid until the gas evolution stops. Evaporate the solution to dryness with clean nitrogen. Add 10 ml of methanol and evaporate the solution to dryness. Acetylate with 0.5 ml (three parts acetic anhydride and two parts pyridine) overnight. Evaporate to a syrupy residue and add 1 ml of water. Evaporate again to dryness to remove the excess acetic anhydride. Dissolve the residue in 250 /d methylene chloride. 

Ab initio molecular orbital calculations are being used to study the reactions of anionic nucleophiles with carbonyl compounds in the gas phase. A rich variety of energy surfaces is found as shown here for reactions of hydroxide ion with methyl formate and formaldehyde, chloride ion with formyl and acetyl chloride, and fluoride ion with formyl fluoride. Extension of these investigations to determine the influence of solvation on the energy profiles is also underway the statistical mechanics approach is outlined and illustrated by results from Monte Carlo simulations for the addition of hydroxide ion to formaldehyde in water. 

The sulfonylated and acylated PPO presents solubility characteristics which are completely different from those of the parent PPO. Table V presents the solubility of some modified structures compared to those of unmodified PPO. It is very important to note that, after sulfonylation, most of the polymers become soluble in dipolar aprotic solvents like dimethyl sulfoxide (DMSO), N,N— dimethylformamide (DMF) and N,N-dimethylacetamide (DMAC). At the same time it is interesting to mention that, while PPO crystallizes from methylene chloride solution, all the sulfonylated polymers do not crystallize and form indefinitely stable solutions in methylene chloride. Only some of the acetylated polymers become soluble in DMF and DMAC, and none are soluble in DMSO. The polymers acetylated with aliphatic acid chlorides such as propionyl chloride are also soluble in acetone. 

Similarly, Shen and coworkers36 obtained 4-0-(2-acetamido-3,4,6-tri-O- acetyl - 2 - deoxy -/ - d- glucopyranosyl) -N- (benzyloxycarbonyl)homo-serinamide (164) by coupling 2-acetamido-3,4,6-tri-0-acetyl-2-deoxy-a-D-glucopyranosyl chloride (6) with 2-N-(benzyloxycarbonylamino)-4-hydroxybutanamide128 (163) in the presence of mercury dicyanide. 

A propoxyphene-like analgesic which obeys the empirical morphine rule is pyrroliphene (101). A Mannich reaction involving pyrrolidine, formaldehyde and propiophenone gave amino ketone 99, which was converted to tertiary carbinol 100 by reaction with benzyl magnesium chloride reaction with acetyl... 

Acetyl chloride reacts with (C5H5)Fe(CO)2 to produce an acyl derivative. 

Acetate A general name for processes for making cellulose acetate fibers. Cellulose is acetylated, dissolved in acetone, and spun into fibers by injecting through orifices into heated chambers. Cellulose mono-acetate is made by acetylating with a mixture of acetic acid, acetic anhydride, and sulfuric acid as the catalyst. Cellulose tri-acetate is made in a similar fashion, but using perchloric acid as the catalyst, and dry-spinning from a solution in ethanol/ methylene chloride. Cellulose tri-acetate fibers were first made commercially by Courtaulds in London in 1950. 

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