Ether from

CiaH3 7N02,CH3-[CH2],2-CH CH.CH(0H). CH(NH2>-CH20H. a base, forming part of the molecules of sphingomyelins and the cerebrosides, from which it splits off on hydrolysis. It crystallizes in needles from ether. 

In a 250 ml. bolt-head flask, fitted with a reflux condenser, place a mixture of 10 g. of benzoin (Section IV,125) and 20 g. (25 ml.) of rectified spirit together with an aqueous solution of 8 0 g. of hydroxylamine hydrochloride which has previously been neutralised with 4-4 g. of sodium hydroxide. Reflux for 60 minutes. Add water to precipitate the benzoinoxime, and cool in an ice bath. Filter the solid with suction at the pump, wash it with water, and recrystaUise from dilute alcohol. Alternatively, the dry sohd may be recrystalhsed from ether. The yield of pure a-benzoinoxime, m.p. 151°, is 5 g. 

The following is an alternative method of purifying the crude aspirin. Dissolve the solid in about 30 ml. of hot alcohol and pour the solution into about 75 ml. of warm water if a sohd separates at this point, warm the mixture until solution is complete and then allow the clear solution to cool slowly. Beautiful needle-like crystals will separate. The yield is 13 g. The air-dried crude product may also be recrystallised from benzene or from ether - light petroleum (b.p. 40-60°). 

A stirred solution of o-methylpivalanilide (50 mmol) in dry THE (100 ml) was maintained at 15°C under a nitrogen atmosphere. A 1.5 M solution of n-butyllithium in hexane (3 equiv.) was added dropwise. The solution was then maintained at room temperature for 16h. The solution was cooled in an ice-bath and treated with 2 N HCl (60 ml). The organic layer was separated and the aqueous layer was further extracted with benzene. The combined layers were dried (MgS04). The product was obtained in 87% yield and recrystallized from ether-cyclohexane. 

The above product (24 g, 0.067 mol) was dissolved in 90 10 dioxane-water (300 ml) and sodium borohydride (92.5 g, 0.067 mol) was added. The mixture was refluxed for 4h. The cooled solution was poured into 0.1 N HCl (1.11). A solid precipitated and was collected by filtration, dried and recrystallized from ether hexane to give 6,7-dibromo-4-methoxyindole (18.5 g, 90%). 

Metal carboxylates are ionic and when the molecular weight isn t too high the sodium and potassium salts of carboxylic acids are soluble m water Carboxylic acids therefore may be extracted from ether solutions into aqueous sodium or potassium hydroxide... 

Allylestrenol. Allylestrenol (37), which has been used to treat cases of habitual abortion (55), can be recrystaUized from ether/petroleum ether (56). It is soluble in acetone, ethanol, ether, and chloroform and practically insoluble in water (57). The uv and ir spectra have been reported (58). AHylestrenol is sensitive to oxidising agents (57). 

Low molecular weight ether hydroperoxides are similarly dangerous and therefore ethers should be tested for peroxides and any peroxidic products removed from them before ethers are distilled or evaporated to dryness. Many ethers autoxidize so readily that peroxidic compounds form at dangerous levels when stored in containers that are not airtight (133). Used ether containers should be handled cautiously and if they are found to contain hazardous soHd ether peroxides, bomb-squad assisted disposal may be required (134). ZeoHtes have been used for removal of peroxide impurities from ethers (135). 

Membrane filtration has been used in the laboratory for over a century. The earliest membranes were homogeneous stmctures of purified coUagen or 2ein. The first synthetic membranes were nitrocellulose (collodion) cast from ether in the 1850s. By the early 1900s, standard graded nitrocellulose membranes were commercially available (1). Their utihty was limited to laboratory research because of low transport rates and susceptibiUty to internal plugging. They did, however, serve a useflil role in the separation and purification of coUoids, proteins, blood sera, enzymes, toxins, bacteria, and vimses (2). 

Another, quite different procedure is the preparation of xanthates from ethers (69) ... 

Ethers. In the presence of anhydrous agents such as ferric chloride (88), hydrogen bromide, and acid chlorides, ethers react to form esters (see Ethers). Esters can also be prepared from ethers by an oxidative process (89). With mixed sulfonic—carboxyhc anhydrides, ethers are converted to a mixture of the corresponding carboxylate and sulfonate esters (90) ... 

CLAY - KINNEAR - PERREN Phosphonyl Chloride Synthesis Synthesis ol alkyl phosphonyl chlorides Irom alkyl chlorides or from ethers with PCI3 AICI3... 

If the nitration is caiiied out in accordance with this outline, the product will be crystalline and pale yellow in color. The color is due to traces of dinitrothiophene and the other impurities. Mononitrothiophene has been crystallized by earlier workers from ether, alcohol, benzene, and other solvents. As a rule these solvents fail to yield a snow-white product. It has been found in this work that petroleum ether (b.p. 20-40 ) possesses decided advantages in that by prolonged refluxing it extracts mononitrothiophene but does not readily dissolve the impurities. With petroleum ether, snow-white crystals have been obtained in needles 10 to 20 cm. in length. 

Chlorobenzenesulfonyl chloride [98-60-2] M 211.1, m 53 , b 141 /15mm. Crystd from ether in powdered Dry-ice, after soln had been washed with 10% NaOH until colourless and dried with Na2S04. 

Distd in steam and crystd from ether/pet ether. 

Dinitrofluorobenzene (Sanger s reagent) [70-34-8] M 186.1, m 25-27 , b 133 /2mm, 140-141 /5mm, d 1.483. Crystd from ether or EtOH. Vacuum distd through a Todd Column (see p. 174). If it is to be purified by distn in vacuo, the distn unit must be allowed to cool before air is allowed into the apparatus otherwise the residue carbonises spontaneously and an EXPLOSION may occur. The material is a skin irritant and may cause serious dermatitis. 

Docosanol (behenyl alcohol) [661-19-8] M 182.3, m 70.8°. Crystd from ether or chloroform/ether. 

Hydroxy-3-methylbutyric (a-hydroxyisovaleric) acid [600-37-3] M 118.1, m 86°, pK, -3.9. Crystd from ether/pentane. 

Hydroxyphenylacetic acid [614-75-5] M 152.2, m 148-149", b 240-243"/760mm, pKEst(i)-4.3, pKEst(2)-10.1. Crystd from ether or chloroform (m from latter is always lower). 

Crystd from water as hydrate, and crystd from ether as the anhydrous base. 

Isonitrosoacetone (unfi-pyruvic aldehyde-l-oxime) [31915-82-9] M 87.1, m 69". Crystd from ether/pet ether or CCI4. 

Naphthoquinone [524-42-5] M 158.2, m 140-142 (dec). Crystd from ether (red needles) or benzene (orange leaflets). 

D. ci - -Thiabicyclo[4 .. Q]nonan S,S-Dioxide [Benzo[c]thiophene 2,2-dioxide, cis-octahydro-]. A solution of the sulfide (43.0 g., 0.303 mole) in 11. of ether is cooled to 0° and treated dropwise while magnetically stirred with 1.01. of 0.65iV ethereal monoperphthalic acid (0.65 mole). The mixture is kept overnight at 0°, after which time the precipitated phthalic acid is separated by filtration and the filtrate concentrated with a rotary evaporator. Bulb-to-bulb distillation of the residual oil at 0.05-0.1 mm. affords the sulfone as a eolorless liquid (48.5-50 g., 92-95%) (Note 11). This product is crystallized from ether-hexane to give a colorless solid, m.p. 39-41° (Note 12). 

The method of oxidation is essentially that of Russigd The product obtained is slightly but definitely better than that produced at a lower temperature, or by adding the sulfuric acid to the dichromate solution, or by using ferric clrloride as in A). These latter procedures give the same yield, but the product is less pure and contains a black, ether-soluble impurity which must be washed out carefully after crystallization from ether. 

In the case of phenyllithium, it has been possible to demonstrate by NMR studies that the compound is tetrameric in 1 2 ether-cyclohexane but dimeric in 1 9 TMEDA-cyclohexane. X-ray crystal structure determinations have been done on both dimeric and tetrameric structures. A dimeric structure crystallizes from hexane containing TMEDA. This structure is shown in Fig. 7.1 A. A tetrameric structure incorporating four ether molecules forms from ether-hexane solution. This structure is shown in Fig. 7.IB. There is a good correspondence between the structures that crystallize and those indicated by the NMR studies. 

By using various trapping reagents, it has been deduced that the transannular fragmentation is rapidly reversible. The cyclization of the fragmented radical C is less favorable, and it is trapped at rates which exceed that for recyclization under most circumstances. " Radicals derived from ethers and acetals by hydrogen abstraction are subject to fragmentation, with formation of a ketone or ester, respectively. 

Tropigenine (nortropine), C,Hi30N. This product of the action of potassium permanganate on tropine is a strong base, which crystallises from ether in colourless needles, m.p. 161° b.p. 233° (picrate, m.p. 170-1° ... 

Oscine, CgHiaOjN, This substance, for which the name scopolin is in use in continental Europe, was first examined by Hesse and later t Luboldt. It forms colourless, hygroscopic prismatic crystals, m.p. 109 from ether or light petroleum, and boils at 241-3°. cZZ-Oscine has bee resolved into the d- and Z-forms by King by crystallisation of tl d-hydrogen tartrates. The characters of the three forms of oscine and ( their picrates and hydrochlorides are tabulated on p. 87. 

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