Of petroleum ether

Cool the flask in ice, acidify with 10 ml. of cold 1 1-hydro-chloric acid and distil under reduced pressure (water pump) until most of the alcohol is removed. Add water to the residue, extract several times with ether, wash the combined ethereal extracts with N ammonia solution until a test portion gives no precipitate upon acidification. Extract the combined alkahne solutions once with a fresh portion of ether, and add the aqueous solution to an excess of dilute hydrochloric acid the final mixture should still be acidic to Congo red. Collect the crystalhne half-ester by filtration at the pump, wash it with water and dry at 100°. The yield is 14-5 g., m.p. 122-125°. Recrystallise by dissolving in about 40 ml. of warm benzene and adding an equal volume of petroleum ether (b.p. 40- 60°) 13 -5 g. of the colourless half-ester, m.p. 125-126°, are obtained. 

An important publication by Kost et al. (63JGU525) on thin-layer chromatography (TLC) of pyrazoles contains a large collection of Rf values for 1 1 mixtures of petroleum ether-chloroform or benzene-chloroform as eluents and alumina as stationary phase. 1,3- and 1,5-disubstituted pyrazoles can be separated and identified by TLC (Rf l,3>i y 1,5). For another publication by the same authors on the chromatographic separation of the aminopyrazoles, see (63JGU2519). A-Unsubstituted pyrazoles move with difficulty and it is necessary to add acetone or methanol to the eluent mixture. Other convenient conditions for AH pyrazoles utilize silica gel and ethyl acetate saturated with water (a pentacyanoamine ferroate ammonium disodium salt solution can be used to visualize the pyrazoles). 

In a typical process a preform billet is produced by compacting a mixture of 83 parts PTFE dispersion polymer and 17 parts of petroleum ether (100-120°C fraction). This is then extmded using a vertical ram extruder. The extrudate is subsequently heated in an oven at about 105°C to remove the lubricant, this being followed by sintering at about 380°C. By this process it is possible to produce thin-walled tube with excellent flexing fatigue resistance and to coat wire with very thin coatings or polymer. 

The hot reaction mixture is poured with stirring over about 0.75 1. of crushed ice in a 2-1. beaker. The beaker is filled with water, and the mixture is stirred to dissolve inorganic salts (Note 5). The insoluble red-brown solid is collected on a suction filter. This crude product, even while damp, is transferred to a 2-1. round-bottomed flask, and 500 ml. of a mixture of 75% (375 ml.) of petroleum ether (b.p. 90-100°) and 25% (125 ml.) of benzene is added. The flask is provided with a reflux condenser, and the mixture is heated at reflux for 15 minutes by means of an electric mantle (Note 6). The resulting solution is decanted into a second 2-1. flask, leaving in the first flask some water and a red-brown solid residue. Po the slightly cooled liquor in the... 

The product is collected on a suction filter. The yield of air-dried product, as yellow-orange crystals, m.p. 87-89°, is 38-42 g. (65-71%) (Note 8). A purer, lemon-yellow product, m.p. 88.5-90°, is obtained by an additional recrystallization from 1 1. of petroleum ether (b.p. 90-100°) with use of carbon the yield after this second crystallization is 28-34 g. (48-58%). 

A suspension of 25.2 g of crude (52) in 250 ml of heavy mineral oil is covered with an atmosphere of nitrogen, stirred, and heated at 330-335° for 5 hr. The solution is then cooled to room temperature, diluted with 500 ml of petroleum ether (bp 35-60°) and filtered. The crude 3-[4-oxo-2-phenyl-3, (4H)-quinazolinyl]estra-l,3,5(10)-trien-17-one (53), which weighs 25 g and exhibits 279 mju (g 14,100), is used directly for the next step. 

The enol lactone (12.7 g) is added to 157 ml of 0.5 M perbenzoic acid in benzene and allowed to stand at 25° for 140 hr. The solution is cooled to 15° and 15% sodium bisulfite solution is added to neutralize the excess peracid. The organic layer is separated and washed with saturated sodium bicarbonate solution and water. The benzene solution is dried over anhydrous sodium sulfate, filtered and concentrated to 30 ml. The product is crystallized by adding 80 ml of petroleum ether, filtered and washed with petroleum ether to yield 12.8 g (98%) of 3a,20,23-trihydroxy-16a-methyl-17(20)-oxido-ll-oxo-21-norchol-22-enoic acid-24(20)-lactone 3,23-diacetate mp 225-227°. 

Although crude cyanoamidine (10) can be used for many reactions, reduction to the 2-formyl-A-norsteroid (11) is most satisfactory when purified material is employed. The crude cyanoamidine is stirred for about 15 min with boiling toluene (120 ml/g of steroid) to effect dissolution, the hot solution is filtered quickly through fluted paper, and the filtrate is cooled and diluted with an equal volume of petroleum ether. The mixture is cooled for 0.5 hr in ice, affording from 25 g of crude material about 18 g of colorless 2a-(A-pyrrolidinylcyanoiminomethyl)-A-nor-5a-androstan-17 -ol (10) mp 252-255° (anal, sample mp 262-263°, from benzene-hexane 250 m ... 

The nitrosite, C,5H24N20j, is formed when zingiberene is dissolved in ten times its volume of petroleum ether, the solution well cooled and treated with a solution of sodium nitrite, and acetic acid added. It ci-ystallises from hot methyl alcohol, and melts at 97° to 98°. 

Thujone is best identified by its tribromo-compound, CjflHjgBrgO, melting at 121° to 122°. It is obtained by adding 5 c.c. of bromine (at once) to a solution of 5 grams of thujone in 30 c.c. of petroleum ether. The tribromo-compound separates on evaporation of the solvent and is washed with alcohol and recrystallised from boiling acetic ether. 

Bayer and Henrich have prepared a bisnitrosopulegone, which is very useful for the identification of the ketone. A solution of 2 c.c. of pulegone in 2 c.c. of petroleum ether is cooled in a freezing mixture and 1 c.c. of amyl nitrite and a trace of hydrochloric acid are added. Fine needles of the bisnitroso compound quickly separate, which, when dried on a porous plate and washed with petroleum ether, melt at 81 5°. 

In judging whether or not petroleum ether should be added, the following rule should be observed Add enough petroleum ether to soften the cineol arsenate, so as to obtain a plastic mass the quantity necessary never exceeds 5 c.c., and decreases vsith oils containing less than 80 per cent, of cineol. The object of adding petroleum ether is merely to soften the hard mass and to aid in the separation of non-cineol constituents of the oil a large excess of petroleum ether will decompose the compound. 

Indol can be isolated from, and determined in, essential oils in the following manner Ihe oil is mixed with 10 per cent, of picric acid and heated to 60°. Excess of petroleum ether is then added. A picric acid compound of indol separates in long red crystals, which are washed with petroleum ether and decomposed by caustic alkali, and the free indol extracted by ether, and the residue left on evaporation of the ether steam-distilled, when pure indol passes over. 

Five c.c. of the oil to be examined are weighed and brought into a glass-stoppered burette graduated to c.c., and is diluted with about, an equal volume of petroleum ether a 5 per cent, potassium hydroxide solution is added, and the mixture shaken for a short time, then the liquid is left standing until separation is complete. Then the alkaline solution is allowed to run into a 100 c.c. graduated flask. This operation is repeated until no further decrease in the volume of the oil takes place. 

The complex is decomposed by stirring the reaction mixture into a solution prepared from 500 g of ammonium chloride in 2,000 ml of water to which 3 kg of crushed ice have been added. After extraction and washing, the ether is evaporated in vacuo at 40°C. The oily residue is taken up in 500 ml of petroleum ether and left to crystallize by cooling at -20°C. The yellowish crystals formed are dried (309 g) MPi< (Kofler block) 74°C yield 92%. 

The final extract is faintly pale yellow in color, whereas the previous extracts are orange. The combined ether extracts are concentrated to dryness and about 3 grams of a reddish-brown residue is obtained. The residue is stirred with approximately 400 cc of petroleum ether for two to three hours, the solvent decanted and the residue treated again with approximately 400 cc of petroleum ether. A pale yellow oil constituting crude actinomycin... 

A mixture of 3 grams (0.01 mol) of 7-chloro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2(1 H)-one 4-oxide, 30 ml of chloroform and 1 ml of phosphorus trichloride was refluxed for one hour. The reaction mixture was then poured on ice and stirred with an excess of 40% sodium hydroxide solution. The chloroform was then separated, dried with sodium sulfate, filtered and concentrated in vacuo. The residue was dissolved in methylene chloride and crystallized by the addition of petroleum ether. The product, 7-chloro-Tmethyl-5-phenyl-3H-1,4-benzodiazepin-2(1 H)-one, was recrystallized from a mixture of acetone and petroleum ether forming colorless plates melting at 125°-126°C. 

A mixture of 39.0 grams (0.2 mol) of a-methylhomoveratrylamine and 42.0 grams (0.2 mol) of 3-methoxy-4-ethoxyphenylacetic acid is heated at 190°-200°C for one hour. The reaction mixture is poured into about 100 cc of petroleum ether, whereupon crystals of N-(a-methyl-homoveratryl)-3-methoxy-4-ethoxyphenylacetamide separate. The precipitate is filtered off, and recrystallized from 50% methanol-water. 

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