Acetic acid in ether

N — n = CH mw 84.08, N 66.64% lt-yel prisms (from eth or benz), mp 125-26°(dec) readily sol in w ale si sol in eth benz can be prepd by reduction of sym-tetrazine with H2S in cold aq soln, or with Zn dust glac acetic acid in ether and from hydrazo-formaldehyde-hydrazone by soln in dil glac acetic acid (Refs 1,2,3 4). Its expl props were not detd... 

Fraction A was obtained by a 2/1 mixture of chloroform and 2-propanol, fraction B was recovered using 2% acetic acid in ether, fraction C was eluted by methanol, and fraction D resulted from elution by a 420/350/100/50/0.5 mixture of hexane, 2-propanol, ethanol, 0.1 M aqueous ammonium acetate and formic acid. 

CaSi does not react quantitatively with acetic acid in ethereal solution, probably because the Ca acetate formed has only a very small solubility in ether279). It yields products with Si-H and Si-OOC-CH3 linkages. The IR absorption band of the Si-H bond is observable at 2100 cm-1, which is a very low frequency. Such low-frequency absorption always occurs when the Si-H bond is vicinal to Si-Si bonds and is easy to chlorinate. In a fast, quantitative reaction with acetic acid in a solution of CCI4, a product of composition [H0 75SiClo.9s(OOC CH3)0.4] was obtained. This composition shows no deficit of substituents and no ESR signal is observable to support the existence of a chain structure. 

To an ice cooled solution of the carboxylic acid in ether or ethanol, add an ethereal solution of diazomethane slowly, until gas evolution stops, and a very pale yellow colour remains. Add just enough dilute acetic acid in ether to remove the yellow colour, then evaporate the mixture and purify the product as appropriate. For very acid-sensitive reactants the acetic acid work-up can be omitted, and excess diazomethane removed by bubbling nitrogen through the reaction mixture (in a good fume cupboard) until all the yellow colour has disappeared. 

We have already alluded above to addition of bromine to [4.2.1]propell-3-ene. The saturated hydrocarbon also adds bromine to the conjoining bond at — 78°C, a reaction analogous to that of acetic acid addition. The same [4.2.1]olefin is hydrogenolyzed across the conjoining bond if platinum is used in acetic acid in ether the [4.2.1]propellane survives. 

Startg. chiral 3-acyl-2-oxazolidone treated with Na-bis(trimethylsilyl)amide in THF at -78°, the resulting Z-enolate alkylated with 3 eqs. methyl bromoacetate, allowed to warm to —20° over 1-2 h, and quenched at — 50° with 2.5 eqs. acetic acid in ether - intermediate (Y 77% d.e. 95%), treated with 2 eqs. 1 Af Na-methoxide in methanol... 

The Ce and Cw are lb mole/ft of acetic acid in ether and water, respectively. A spray column (3-inch i.d., 10 feet high, no packing) is used to extract downward flowing acetic acid-water (1.62 ft/hr) by upward flowing drops of ether (3.90 ft/hr)... 

To absolution of 1.00 mol of ethyl lithium in 800-900 ml of diethyl ether (see Chapter II, Exp. 1) was added, with cooling between -20 and -10°C, 0.50 nol of dry propargyl alcohol, dissolved in 100 ml of diethyl ether. Subsequently 1.1 mol of trimethylchlorosilane was introduced over a period of 25 min with cooling between -15 and +5°C. After stirring for an additional 2 h at about 30°C the suspension was poured into a solution of 30 g of acetic acid in 150 ml of water. After stirring for 1 h at room temperature the layers were separated and the aqueous layer v/as extracted four times with diethyl ether. The combined ethereal solutions were washed with sodium hydrogen carbonate solution in order to neutralize acetic acid, and were then dried over magnesium sulfate. The diethyl ether was removed by evaporation in a water-pump vacuum and the residue distilled... 

Bromoacetic acid can be prepared by the bromination of acetic acid in the presence of acetic anhydride and a trace of pyridine (55), by the HeU-VoUiard-Zelinsky bromination cataly2ed by phosphoms, and by direct bromination of acetic acid at high temperatures or with hydrogen chloride as catalyst. Other methods of preparation include treatment of chloroacetic acid with hydrobromic acid at elevated temperatures (56), oxidation of ethylene bromide with Aiming nitric acid, hydrolysis of dibromovinyl ether, and air oxidation of bromoacetylene in ethanol. 

One can readily appreciate the usefulness of pK value in purification procedures, e.g. as when purifying acetic acid. If acetic acid is placed in aqueous solution and the pH adjusted to 7.76 [AcOH]/[AcO ] with a ratio of 0.1/99.9], and extracted with say diethyl ether, neutral impurities will be extracted into diethyl ether leaving almost all the acetic acid in the form of AcO in the aqueous solution. If then the pH of the solution is adjusted to 1.67 where the acid is almost all in the form AcOH, almost all of it will be extracted into diethyl ether. 

Ferrocene (46.4 g., 0.250 mole) (Note 1) is added to a well-stirred solution of 43.2 g. (0.422 mole) of bis(dimethylamino)-methane (Note 2) and 43.2 g. of phosphoric acid in 400 ml. of acetic acid in a 2-1. three-necked round-bottomed flask equipped with a condenser, a nitrogen inlet, and a mechanical stirrer (Note 3). The resulting suspension is heated on a steam bath under a slow stream of nitrogen (Note 4) for 5 hours (Note 5). The reaction mixture, a dark-amber solution, is allowed to cool to room temperature and is diluted with 550 ml. of water. The unreacted ferrocene is removed by extracting the solution with three 325-ml. jiortions of ether. The aqueous solution is then looled in ice water and made alkaline by the addition of 245 g. 

This formula was confirmed hy Haworth and Perkin s synthesis of a-flZZocryptopine from herherine, the first application of a process, of which examples have heen given already in the syntheses of cryptopine (p. 298) and protopine (p. 301) hy the same authors. Anhydrotetrahydromethyl-herherine (I cf. hase (a), p. 346) in dry chloroform was added to a solution of perhenzoic acid in ether cooled helow 5°. The amine oxide, C21H23O5N (II), separated as an oil, which after shaking with sodium hydroxide solution, solidified and was crystallised from water in slender prisms, m.p. 135°. It was dissolved in acetic acid, hydrochloric acid added, the mixture heated in boiling water for an hour and the hase precipitated hy addition of potassium hydroxide. The precipitate was dissolved in methyl alcohol, ether added, the alcohol washed out with water and the ethereal... 

A decisive solvent effect is also observed with other a,/ -epoxy ketones. Specifically, 3jS-hydroxy-16a,17a-epoxypregn-5-en-20-one and its acetate do not react with thiocyanic acid in ether or chloroform. However, the corresponding thiocyanatohydrins are formed by heating an acetic acid solution of the epoxide and potassium thiocyanate. As expected, the ring opening reaction is subject to steric hindrance. For example, 3j6-acetoxy-14f ,15f5-epoxy-5) -card-20(22)-enoIide is inert to thiocyanic acid in chloroform, whereas the 14a,15a-epoxide reacts readily under these conditions.Reactions of 14a,15a-epoxides in the cardenolide series yields isothiocyanatohydrins, e.g., (135), in addition to the normal thiocyanatohydrin, e.g., (134). 

Protonation of the anion [SN2] by acetic acid in diethyl ether produces the thermally unstable sulfur diimide S(NH)2. Like all sulfur diimides, the parent compound S(NH)2 can exist as three isomers (Scheme 5.5). Ab initio molecular orbital calculations indicate that the (cis,cis) configuration is somewhat more stable than the (cis,trans) isomer, while the (trans,trans) isomer is expected to possess considerably higher energy. The alternative syn,anti or E,Z nomenclatures may also be used to describe these isomers. The structures of organic derivatives S(NR)2 (R = alkyl, aryl) are discussed in Section 10.4.2. 

A 250-ml three-necked flask is equipped with a dropping funnel, a thermometer, and a mechanical stirrer, and is charged with a solution of 22 g (0.10 mole) of 4-benzoyl-oxycyclohexanol (Chapter 7, Section X) in 40 ml of acetic acid. The solution is cooled in a water bath, and the oxidizing solution is added at a rate so as to maintain the reaction temperature below 35°. After completion of the addition, the reaction mixture is allowed to stand at room temperature overnight. The mixture is extracted with 150 ml of ether, and the ethereal solution is washed four times with 100-ml portions of water to remove the bulk of the acetic acid. The ethereal solution is then washed with sodium bicarbonate solution followed by water and then dried over sodium sulfate. The ether is evaporated, and the residue solidifies. The product keto ester may be recrystallized from ether-p>etroleum ether giving plates, mp 62-63°. The yield is about 18 g (82 %). 

The identification of camphene is best carried out by its conversion into isobomeol under the influence of acetic acid in the presence of sulphuric acid. In order to effect this conversion, 100 grams of the fraction containing the terpene in substantial quantity are mixed with 250 grains of glacial acetic acid and 10 grams of 50 per cent, sulphuric acid. Tne mixture is heated for two to three hours on a water-bath to a temperature of 50° to 60°. At first the liquid separates into two layers, bat soon becomes homogeneous and takes on a pale red colour. Excess of water is added, and the oil which is precipitated, and which contains the isobomeol in the form of its acetate, is well washed with water repeatedly. It is then saponified by heating with alcoholic potash solution on a water-bath. The liquid is then evaporated and extracted with water, and the residue recrystallised from petroleum ether. 

Bornyl Acetate.—The acetic acid ester is the most important of the series. It is a constituent of pine-needle and rosemary oils, and has a most fragrant and refreshing odour. It is prepared artificially by the action of acetic anhydride on borneol, in the presence of sodium acetate, or by the condensation of borneol with glacial acetic acid in the presence of a small amount of a mineral acid. It is absolutely necessary in the reproduction of any pine odour. It is a crystalline body, crystallising from peDroleum ether in rhombic hemihedric crystals melting at 29°. The optical activity depends on that of the borneol from which it has been prepared. It has the following characters —... 

IB) 1-(2-Amino-5-chlorophenyl)-1-(2-fluorophenyl)-3,3-bis-(ethoxycarbonyl)-2-a2a-prop-1-ene A mixture of 88 g of the product obtained above, 300 g of ethyl aminomalonate hydrochloride and 60 ml of acetic acid in 2.3 liters of absolute ethanol is heated to the reflux temperature for 6 hours. The alcohol and the acetic acid are evaporated in vacuo and the residue is taken up in ether. The solution is washed with a dilute sodium bicarbonate solution and... 

This reaction mixture is kept between 0°C and -i-5°C for six hours, with agitation and under an inert atmosphere, then 5 cc of a 0.2N solution of acetic acid in toluene are added. The mixture is extracted with toluene, and the extracts are washed with water and evaporated to dryness. The residue is taken up in ethyl acetate, and then the solution Is evaporated to dryness in vacuo, yielding a resin which is dissolved in methylene chloride, and the solution passed through a column of 40 g of magnesium silicate. Elution is carried out first with methylene chloride, then with methylene chloride containing 0.5% of acetone, and 0.361 g Is thus recovered of a crude product, which is dissolved in 1.5 cc of isopropyl ether then hot methanol Is added and the mixture left at 0°C for one night. 

To a cold (—78 C) solution of 0.8 g (3.9 mmol) of 3-(phenylsulfinyl)-l-cyclohcxcnc in 20 mL of THF is added a cold ( — 78 lC) solution of 4.37 mmol of LDA in 20 mL of THF via a cannula. The resulting yellow solution is stirred at —78 C for 30 min, and then 0.7 mL (4.0 mmol) of HMPA is added, followed after 5 min by the addition of 0.320 g (3.9 mmol) of 2-cyclopentenone, and the solution is stilted at —78 C for 15 min. A solution of 0.26 mL of acetic acid in 2 mL of diethyl ether is added and the solution warmed to 25 C, diluted with aq NH4C1, and extracted with three portions ol diethyl ether. The combined extracts are washed with aq NaCl, dried over MgSC)a, concentrated, and column chromatographed to give the title compound yield 0.562 g (50%). Starting sulfoxides and enones were also recovered. 

To a stirred solution of 0.74 g (4 mmol) of (S)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazine in 20 mL of THF under a nitrogen atmosphere are added at — 70 °C, 2.6 mL (4 mmol, 1.55 N in hexane) of butyllithium and stirring is continued for 10 min. Then, a solution of 0.97 g (6 mmol) of methyl (/f)-3-phenylpropenoate in 10 mL of THF is added. After 2 3 h a solution of 0.24 g (4 mmol) of acetic acid in 2 mL of THF is added and the mixture is allowed to warm to 25 rC. The solvent is removed in vacuo, the residual product dissolved in 10 mL of diethyl ether, then shaken with 10 mL of water, and the water layer extracted twice with 10 mL of diethyl ether. The combined diethyl ether extracts are dried over MgS04 and the diethyl ether is evaporated. The crude product is purified by bulb-to-bulb distillation to give the adduct yield 1.28 g (92%). 

Chromatography of Nonsaponifiable Lipids. The nonsaponifiable residue plus 4.5 mg. of carrier cholesterol was applied to the top of a 7.5 X 1.7 cm. column containing 20 grams of Merck alumina (suitable for chromatographic adsorption) which had been previously deactivated by mixing with 7% aqueous acetic acid (10% glacial acetic acid in distilled water) (18). The column was packed in petroleum ether (redistilled, b.p. 60-70° C.) and 10 ml. fractions were collected. The eluting solvents are shown in Table II. 

The positive bromination of aromatics ethers was first studied by Bradfield et al.193 and by Branch and Jones194. The reaction of hypobromous acid in 75 % aqueous acetic acid with benzyl 4-nitrophenyl ether and 4-nitrophenetole at 20 °C was very rapid and approximately second-order193. The value of k2/[H+] remained constant in the [H+] range 0.005-0.090 M for the effect of added mineral acids on the bromination of 4-nitroanisole and 4-nitrophenetole (at 19.8 °C)194. The variation in reaction rate with the percentage of acetic acid in the medium was also studied and showed a large increase in the 0-10 % range with a levelling off at approximately 25 % acetic acid (Table 52) this was attributed... 

To make a peroxide test, place a few milligrams of sodium iodide, a trace of ferric chloride, and 2-3 ml. of glacial acetic acid in a test tube and carefully add 1-2 ml. of the ether solution. 

In a variation of this procedure that gives a nearly quantitative yield of good material, the intermediate salt is dissolved in 250 ml. of glacial acetic acid in a 2-1. beaker, and 100 g. of 50% fluoboric acid is added with stirring. When the evolution of gas has stopped, 11. of ethyl acetate is added to precipitate tropylium fluoborate. The fluoborate is separated by filtration, washed successively with ethyl acetate and ether, and dried in an oven at 40°.4... 

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