Sodium acetate, acetic anhydride anhydrous, preparation

Carry out this preparation precisely as described for the a-compound, but instead of zinc chloride add 2 5 g. of anhydrous powdered sodium acetate (preparation, p. 116) to the acetic anhydride. When this mixture has been heated on the water-bath for 5 minutes, and the greater part of the acetate has dissolved, add the 5 g. of powdered glucose. After heating for I hour, pour into cold water as before. The viscous oil crystallises more readily than that obtained in the preparation of the a-compound. Filter the solid material at the pump, breaking up any lumps as before, wash thoroughly with water and drain. (Yield of crude product, io o-io 5 g.). Recrystallise from rectified spirit until the pure -pentacetylglucose is obtained as colourless crystals, m.p- 130-131° again two recrystallisations are usually sufficient for this purpose. 

J The hexa.acetyl derivative, m.p. 121°, may be prepared as follows. Boil under reflux 1 part of mannitol with 5 parts by weight of acetic anhydride and 1 part of anhydrous sodium acetate or with a little anhydrous zinc chloride for 15-20 minutes, pour into excess of water, stir the mixture until the oil has solidifled, and then recrystallise from methylated spirit. 

The important chemical properties of acetyl chloride, CH COCl, were described ia the 1850s (10). Acetyl chloride was prepared by distilling a mixture of anhydrous sodium acetate [127-09-3J, C2H202Na, and phosphorous oxychloride [10025-87-3] POCl, and used it to interact with acetic acid yielding acetic anhydride. Acetyl chloride s violent reaction with water has been used to model Hquid-phase reactions. 

Bisa.codyl, 4,4 -(2-PyridyLmethylene)bisphenol diacetate [603-50-9] (Dulcolax) (9) is a white to off-white crystalline powder ia which particles of 50 p.m dia predominate. It is very soluble ia water, freely soluble ia chloroform and alcohol, soluble ia methanol and ben2ene, and slightly soluble ia diethyl ether. Bisacodyl may be prepared from 2-pyridine-carboxaldehyde by condensation with phenol and the aid of a dehydrant such as sulfuric acid. The resulting 4,4 -(pyridyLmethylene)diphenol is esterified by treatment with acetic anhydride and anhydrous sodium acetate. Crystallisation is from ethanol. 

Preparation of Bisacodyl 5 grams of (4,4 -dihydroxy-diphenyl)-(pyridyl-2)-methane are heated with 5 grams of anhydrous sodium acetate and 20 cc of acetic anhydride for three hours over a boiling waterbath. The cooled reaction mixture is poured into water, whereby after a while a colorless substance precipitates, which Is filtered off with suction, washed with water and recrystallized from aqueous ethanol. Colorless bright crystals, MP 138°C are obtained. 

Dodecatrien-1-ol, 3,7,11-trimethyl-, (E,E)-] (Note 1) and 40 ml. of dry pyridine (Note 2) is prepared in a stoppered 250-ml. Erlenmeyer flask, and 40 ml. of acetic anhydride is added in four portions over a 15-minute period. The mixture is stirred well and allowed to stand for 6 hours and then poured onto 250 g. of ice. Water is added (400 ml.), and the mixture is extracted with five 100-ml. portions of petroleum ether (b.p. 60-68°). The organic extracts are combined and washed in succession with two 50-mi. portions each of water, 5% aqueous sulfuric acid, and saturated aqueous sodium bicarbonate. Anhydrous magnesium sulfate (ca. 50 g.) is used to dry the petroleum ether solution, which is then concentrated on a rotary evaporator to provide 28-29 g. (94-98%) of famesyl acetate as a colorless oil (Note 3). 

A large number of reagents are available for the preparation of nitro PAHs. These include fuming nitric acid in acetic acid (20) or acetic anhydride (13), sodium nitrate in trifluoroacetic acid (21) or trifluoroacetic acid and acetic anhydride (17), dinitrogen tetroxide in carbon tetrachloride (22), sodium nitrate in trimethyl phosphate and phosphorus pentoxide (23), and nitronium tetrafluoroborate in anhydrous acetonitrile (24). Alternative approaches must be used to synthesize nitro PAHs substituted at positions other than the most reactive carbon. For instance,... 

Acetyl chloride (54 g. =075 mole) is allowed to run drop by drop from a tap funnel on to 80 g. of finely powdered anhydrous sodium acetate prepared in the manner described below. When about half of the chloride has been added the experiment is interrupted for a short time in order to stir the pasty mass of material with a bent glass rod, the lower end of which has been flattened. The rest of the acetyl chloride is then run in at such a rate that none passes over unchanged. The anhydride is now distilled from the residual salt by mean of a luminous flame kept constantly in motion. Complete conversion of the last traces of unchanged acetyl chloride to acetic anhydride is attained by adding 3 g. of finely powdered anhydrous sodium acetate to the distillate, which is finally fractionally distilled. Boiling point of acetic anhydride 138°. Yield 55-60 g. Use for acetylation, in Perkin s synthesis (Chap. V. 8, p. 232), preparation of acetophenone (Chap. IX. 3 6, p. 346). 

Phenyl cinnamate and other phenolic esters have been prepared by heating the acid and phenol in the presence of phosphorus oxychloride,1 and by heating the acid anhydride and phenol together in the presence of a dehydrating agent such as fused zinc chloride or anhydrous sodium acetate.2 Phenyl cinnamate has also been prepared by the careful distillation of phenyl fumarate.3... 

Preparation of nitrile acetates from oximes with sodium acetate and acetic anhydride. Pentaacetyl-v-glucononitrile. If only the nitrile is needed, isolation of the oxime can be avoided. One hundred grams of anhydijous n-glucose was dissolved in 50 ml. of warm water, and maintaining the temperature at 60°, a solution of 28 g. of hydro-xylamine in 700 ml. of ethanol was added sufficiently slowly that no precipitation took place. After one hour at 65°, the reaction mixture was concentrated under reduced pressure to a thick sirup. The residue was mixed with absolute ethanol, the ethanol evaporated and the operation repeated in order to eliminate all water. One hundred and twenty grams of anhydrous sodium acetate and 700 ml. of acetic anhydride were added to the sirup, and the mixture was slowly and cautiously warmed in a water bath to 95°. It was advisable to agitate the flask continuously and to watch the... 

Carboxy-2-pyridylthio)propionic acids, prepared by the reaction of 2-mercatopyridin-3-carboxylic acid with 3-bromopropionic acid in aqueous KOH, undergo cyclization upon treatment with anhydrous sodium acetate and acetic anhydride to afford 2,3-dihydrothiopyrano[2,3-3]pyridin-4(4//)-ones. These products undergo further reaction with phenylhydrazine to give the phenylhydrazone (isolated) and then Fischer indole cyclization to give novel 5/7,1177-pyrido[2, 3 2,3]thiopyrano[4,3-3]indoles <2000JHC379>. 

The above procedure is a very slight modification of a recently described 1 general method for condensing ketones with ethyl cyanoacetate. Ethyl (l-ethylpropylidene)-cyanoacetate also has been prepared by condensing diethyl ketone with ethyl cyanoacetate in the presence of piperidine or acetic anhydride and zinc chloride,5 or piperidine and anhydrous sodium sulfate in a pressure bottle at 100°.6... 

The preparation of the first unsaturated azlactone was reported in 1883 by Plochl/40 who condensed benzaldehyde with hippuric acid in presence of acetic anhydride. This approach was later used by Erlenmeyer/41 who extended the procedure to include other aldehydes and also established the usefulness of azlactones as intermediates in the synthesis of DHAs. The method involves the condensation of an A-acylglydne 4 with aldehydes and ketones in the presence of acetic anhydride and anhydrous sodium acetate (Scheme 2)J41 t5l Other catalysts such as copper(II) acetate/46 lead acetate/47,48 potassium carbonate/49 or potassium hydrogen carbonate 50 have also been used. The reaction proceeds via formation of an azlactone 5, which then condenses with the appropriate aldehyde or ketone to give unsaturated azlactone 6. Reaction of 6 with a nucleophile such as OH, OR, or NHR leads to the corresponding A-acyl-DHA derivatives 7. Reaction with the sodium salt of an amino acid gives a DHA containing dipeptide acid. 51 ... 

Esterification is effected in the cold in presence of alkali or by heating the alcohol and anhydride together, usually in presence of a dehydrating agent—e.g., fused zinc chloride, anhydrous sodium acetate, etc. Preparation 204.—Mannitol Hexacetate. 

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