Recrystallization alumina

The organic layer is separated, evaporated on a steam bath, and the dark semicrystalline residue is distilled with steam to remove biphenyl. The contents of the steam-distillation flask are then extracted with ether (Note 3), and the ethereal layer is separated, dried over magnesium sulfate, and percolated through a short column of chromatographic alumina (Notes 4 and 5). Evaporation of the ethereal solution gives crude triphenylene which is sublimed at 175-180° and 0.1 mm. pressure. After rejection of an initial sublimate of impure biphenyl, the sublimed material forms nearly colorless crystals, m.p. 186-194° (Note 6). Yield 8-9 g. (53-59%). It may be further purified by recrystallization from a mixture of methylene chloride and pentane yielding colorless crystals, m.p. 199° (Note 7). 

A solution of this product in cyclohexane is chromatographed on alumina elution with benzene and benzene-25 % ether yields 2.29 g of material which on recrystallization from cyclohexane gives pure hydroxy ketone, mp 151-152°. 

The mixture is cooled to room temperature, then filtered. The solvent is removed under reduced pressure, leaving the tribromide (47) as a foam. The foam is mixed with sodium iodide (9.55 g, 0.064 mole) and acetone (74 ml) and heated under reflux in a nitrogen atmosphere for 3.5 hr. The acetone is removed under reduced pressure and the residue is treated with chloroform and aqueous sodium thiosulfate solution. The chloroform layer is separated and washed with sodium thiosulfate solution until it is free from iodine, then dried over magnesium sulfate, filtered and evaporated to dryness under reduced pressure. The crude product (48) is obtained as a brown sohd (4.85 g) which is chromatographed over alumina (122 g, Merck acid-washed). The column is developed with hexane, benzene and ethyl acetate mixtures. The product (3.43 g) is eluted by benzene and benzene-ethyl acetate (10 1). Recrystallization from acetone yields purified 3jS-acetoxy-pregna-5,14,16-trien-20-one (48), 3.25 g, mp 158-159° 309 m/ (e 10,700). 

A solution of 500 mg 3 -acetoxypregn-5-en-20-one-[17a,16a-c]-A -pyrazoline in 100 ml of anhydrous dioxane is stirred with a magnetic stirrer and irradiated in a water-cooled quartz reactor with a high pressure Biosol Philips 250 W quartz lamp for 1 hr. The solvent is removed at reduced pressure and the residue is chromatographed on alumina (activity III). Elution with petroleum ether-benzene (3 1) gives 0.2 g (42%) of 3 -acetoxy-16a,17a-methylene-pregn-5-en-20-one mp 193-193.5° after two recrystallizations from methylene dichloride-ethyl acetate. 

A mixture consisting of 0.69 g (10.5 mmoles) of zinc-copper couple, 12 ml of dry ether, and a small crystal of iodine, is stirred with a magnetic stirrer and 2.34 g (0.7 ml, 8.75 mmoles) of methylene iodide is added. The mixture is warmed with an infrared lamp to initiate the reaction which is allowed to proceed for 30 min in a water bath at 35°. A solution of 0.97 g (2.5 mmoles) of cholest-4-en-3/ -ol in 7 ml of dry ether is added over a period of 20 min, and the mixture is stirred for an additional hr at 40°. The reaction mixture is cooled with an ice bath and diluted with a saturated solution of magnesium chloride. The supernatant is decanted from the precipitate, and the precipitate is washed twice with ether. The combined ether extracts are washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent is removed under reduced pressure and the residue is chromatographed immediately on 50 g of alumina (activity III). Elution with benzene gives 0.62 g (62%) of crystalline 4/5,5/5-methylene-5 -cholestan-3/5-ol. Recrystallization from acetone gives material of mp 94-95° Hd -10°. 

Methoxy-cis-19-norpregna-l,3,5(10),17(20)-tetraene A solution of 31 g (109 mmolesi of estrone methyl ether in 600 ml of benzene is added rapidly to a solution of 469 mmoles of ethylidenetriphenylphosphorane in 1.2 liters of DMSO. After heating under nitrogen at 60° overnight, the reaction is cooled, poured into ice water, and extracted with three portions of hexane, backwashed with three portions of water and the hexane removed. The crude product, dissolved in petroleum ether (bp, 30-60°), is filtered through 225 g of alumina (activity I). The residue from the eluate consists of 95 % cis- and 5 % tran5-isomers, as determined by vpc analysis. After recrystallization from ether-methanol, 26.3 g (82%) of cw-isomer is obtained mp 76.5-77.5° [a]o 60°. 

The crude ketone is chromatographed on acid-washed alumina (600 g, activity II). Elution with hexane-ether (4 1) gives a white solid (8.5 g) as the major fraction mp 77-82°. Recrystallization from methanol gives A-homo-5a-cholestan-4-one (3b 5.77 g 41% yield) mp 86-88° ... 

After stirring for 1 hr more, the reaction mixture is diluted with 500 ml of cold water the yellow precipitate which forms is filtered, washed and dried, to give 4.1 g (83%) of crude 16-diazoestrone methyl ether (94) mp 133-136°. Chromatography of the crude product over neutral alumina in chloroform, followed by recrystallization from chloroform-methanol, gives pure (94) mp 145-146°, in 64% over-all yield. ... 

A solution of resorcinol (11 g) in sodium hydroxide solution (4.8 g of sodium hydroxide in 20 ml of water) is hydrogenated in the presence of 1.1 g of 5 % rhodium on alumina for 16-18 hours at 50 psi initial pressure in a Parr apparatus. The reduction stops after the absorption of 1 equivalent of hydrogen. The catalyst is removed by filtration through celite, and the aqueous solution is carefully acidified with concentrated hydrochloric acid at 0°. The crude product is collected by filtration, dried in air, and recrystallized from benzene to give 1,3-cyclohexanedione, mp 105-107. ... 

Diazocamphor A large wide-diameter chromatography column (8.5 cm diameter) is packed with 1000 g of basic chromatography grade alumina. The previously prepared solution of the monotosylhydrazone is filtered, if necessary, to remove solids, then poured directly onto the alumina, and the column is eluted with chloroform. The solution of diazocamphor thus obtained is evaporated yielding the desired product. It may be recrystallized from hexane, mp IS. ... 

A mixture of 2.0 grams of 2,3-dihydroxylmino-17a -methyl-5a -androstan-17/3-ol, 5 ml of piperidine and 10 ml of ethylene glycol was heated at a temperature between 180° and 190°C for 30 minutes. After the resulting product was cooled, water was added thereto, and the separated product was filtered, washed with water and dried. The product was dissolved in benzene and passed through a column of alumina. The column was washed with ether, and the eluted fractions were collected and condensed. Subsequently, the residue was recrystallized from ether or aqueous methanol to produce 1.53 grams of 17/3-hy-droxy-17o-methyl-5o-androstano[2,3-C] furazan which has a melting point of 152°C. 

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