Alumina basic

Allylation under basic conditions. Allylation can be carried out under basic conditions with allylic acetates and phosphates, and under neutral conditions with carbonates and vinyloxiranes. The allylations under neutral conditions are treated separately in Section 2.2.2.1 from those under basic conditions. However, in some cases, allylations of the same substrates are carried out under both basic and neutral conditions to give similar results. These reactions are treated together in this section for convenience. Allylic acetates are widely used for Pd-catalyzed allylation in the presence of bases tertiary amines or NaH are commonly used[6,7,4l]. As a base, basic alumina or ICF on alumina is conveniently used, because it is easy to remove by filtration after the reaction[42]. Allyl phosphates are more reactive than acetates. The allylation with 40 proceeds stepwise. At first allylic phosphate reacts with malonate and then allylic acetate reacts with amine to give 41(43]. 

Diehloromethane was purified by percolation through Woelm activity grade 1 basic alumina and stored under nitrogen. 

Rapid purification Pass through a column of basic alumina (Grade 1, lOg/mL of CHCI3), and either dry by standing over 4A molecular sieves, or alternatively, distil from P2O5 (3% w/v). Use immediately. 

Passed through a column of basic alumina and distd. 

Isononane [34464-40-9] M 128.3, b 142"/760mm. Passed through columns of activated silica gel and basic alumina (activity 1). Distd under high vacuum from Na/K alloy. 

Dried with Linde type 5A molecular sieves or Na2S04 and fractionally distd at reduced pressure. Alternatively, it was refluxed with, and distd from, BaO. Also purified by fractional crystn from the melt and distd from zinc dust. Converted to its phosphate (m 135°) or picrate (m 223°), which were purified by crystn and the free base recovered and distd. [Packer, Vaughn and Wong J Am Chem Soc 80 905 1958.] The procedure for purifying via the picrate comprises the addition of quinoline to picric acid dissolved in the minimum volume of 95% EtOH to yield yellow crystals which are washed with EtOH and air dried before recrystn from acetonitrile. The crystals are dissolved in dimethyl sulfoxide (previously dried over 4A molecular sieves) and passed through a basic alumina column, on which picric acid is adsorbed. The free base in the effluent is extracted with n-pentane and distd under vacuum. Traces of solvent are removed by vapour phase chromatography. [Mooman and Anton J Phys Chem 80 2243 1976.]... 

Metbylcyclobexene [591-49-1] M 96.2, b 107.4-108 /atm, 110-lll /760mm, d 0.813, n 1.451. Freed from hydroperoxides by passing through a column containing basic alumina or refluxing with cupric stearate, filtered and fractionally distd from sodium. 

The dibutyl ether must be dry and peroxide-free. This can be achieved by filtering it through a large column of basic alumina, or by leaving overnight over sodium wire and distillation. If these precautions are not observed, low yields result. The checkers purified dibutyl ether by distillation from sodium hydride dispersion. 

Treatment of 2- p-hydroxyphenyl)ethyl bromide with basic alumina produces a white solid mp, 40-43°C IR, 1640cm Uy 282nm in H20,261 mm in ether NMR, two singlets of equal intensity at 1.69 and 6.44 ppm ftom TMS. Anah C, 79.97 H, 6.71. Suggest a reasonable structure for this product and a rationalization for its formation. 

To a solution of 0.5 g of lithium aluminum hydride in 35 ml of ether is added 0.2 g of the A -cyanoaziridine. The mixture is heated at reflux temperature for 3.5 hr, cooled, and treated with excess saturated sodium sulfate in water. Filtration and evaporation of the ethereal filtrate gives 0.18 g of a glass which is chromatographed on 10 g of basic alumina (activity III). The benzene-petroleum ether (1 3) eluate gives 0.12 g of 2a,3a-imino-5a-choles-tane, mp 117.5-118.5°, after crystallization from methanol. 

Column Chromatography Column Chromatography is a useful separation technique for mixtures resulting from intermediate to small scale synthetic processes. For example, nitroferrocene is conveniently isolated from a mixture of the product, ferrocene, and l,r-dinitroferrocene by chromatography on Activity I basic alumina at about the 100-g scale (Chapter 7, Section XI). 

A solution of 3-oxatetracyclo[3.2.0.02 7.04 f,]heptane (941 mg, 10 mmol) in anhyd benzene (10 mL), that had been treated with basic alumina prior to the experiment, was heated in a sealed tube for 4 h at 100 C. After cooling, Et2G (10 mL) was added. The mixture was chromatographed (silica gel, 30 g, Et20/pentane 7 3) to yield benzene as the first fraction and 900 mg (95%) of product. After careful evaporation of the Et20/pentane mixture, the product was purified by distillation to give a light yellow oil. 

A solution of ethyl diazo(2,4,6-trimethyl-4//-pyran-4-yl)acetate (0.47 g, 2.0 mmol) in benzene (50 mL) was stirred with // -allylpalladium chloride dimer (15 mg) for 2h at rt, and then the solvent was evaporated. The residue was chromatographed (80-g basic alumina, EtOAc/hexane 1 2) yield 0.40 g (97 %) yellow oil. 

Allylic bromination, with A -bromosuccinimide (NBS), of 4-ethoxy-l,2-dihydrocyclo-pent[rf]azepine (8), formed by ethylation (with Meerwein s reagent) of the corresponding 4-oxo derivative, followed by in situ dehydrobromination of the resulting bromo compound with basic alumina, produces a low yield of l-bromo-2-ethoxycyclopent[c/]azepine (9) as a photosensitive, sapphire-blue, crystalline solid.55... 

Alumina chromatography The butanol extract containing F is poured onto a column of alumina (2.6 x 9 cm Woelem basic alumina Grade 1), and F adsorbed is eluted with 50% ethanol containing 0.6% ammonium hydroxide. The fractions containing F are combined (a trace of Tris is added) and concentrated to about 5 ml, and mixed... 

A solution of potassium naphthalenide is prepared from 2.0 g (50 mmol) of potassium and 6.4 g (50 mmol) of naphthalene in 40 mL ofTHF. After 1 h at r.t. this mixture is diluted with 10 mL of diethyl ether and 10 mL of petroleum ether (bp 40-60 °C) and cooled to — 120 °C. 4.5 g (25 mmol) of ( )-l-methoxy-3-phenylthio-1-propcne arc added followed by 3.36 g (25 mmol) of chlorobis(l-dimethylamino)borane. This mixture is allowed to warm to r.t. over 3 h the solvents are removed in vacuo and the residue is carefully distilled through a 5-cm column at 10 2 Torr. The distillate, containing also naphthalene, is dissolved in 30 mL of diethyl ether and treated with 2.95 g (25 mmol) of pinacol for 3 h. The crude product is chromatographed over 30 g of basic alumina (activity 1) using petroleum ether (bp 40 -60°C) giving 9.2 g of a mixture of product and naphthalene the yield of product (89% E) is determined to be 60% by H-NMR analysis. Similarly prepared is ... 

Proton magnetic resonance (CDC13) 8, number of protons, multiplicity, coupling constant J in Hz. 1.5-2.2 (2, multiple ), 2.7-3.0 (4, multiplct), 7.0 (1, doublet, J = 2.5), 7.1-7.5 (6, multiplet), 7.7-8.2 (4, multiplet). A sample recrystallized from methanol-chloroform melted at 183-185°. The submitters also obtained pure product, m.p. 181-183°, after chromatography on basic alumina with 20% petroleum ether in dichloromethane as eluent. 

Potent antimicrobial l,2,4-triazolo[3,4-fc]-l,3,4-thiadiazepines derivatives were prepared from readily accessible substituted 2-mercapto-l-aminotria-zoles and substituted chalcones on basic alumina in a solvent-free microwave-assisted synthesis (Scheme 28). Exposure of the reaction mixtures to microwaves led to an important decrease of the reaction time, which has been brought down from hours to seconds, accompanied by improved yields as compared with conventional heating [36]. This facile, rapid, and economic... 

A novel method has been developed for the selective N-arylation of indoles with aryl electrophiles in the presence of potassium fluoride adsorbed onto basic alumina <96TL299>. 

A special feature of aluminum oxides is the fact that these sorbents are adjusted to different pH values for thin-layer chromatographic purposes. The acidic aluminas are in the pH range of 4.0 to 4.5, whereas neutral signifies a pH range between 7.0 and 8.0, and basic aluminas have a pH value of approximately 9.0 to 10.0. 

Aluminum oxide 60 G neutral Aluminum oxide 60 GF254 neutral Aluminum oxide G Aluminum oxide G/UV254 Aluminum oxide N Alumina Neutral Alumina Basic Alumina Acid Alumina Basic for TLC Alumina Neutral for TLC Alumina Acid for TLC Alumina with Gypsum for TLC MP Alumina B-TLC MP Alumina N-TLC MP Alumina A-TLC MP Alumina G-TLC... 

General procedure for the Heck reaction. A mixture of iodobenzene (5 mol equ.), diisopropylethylamine (3 mol equ.), 2,3-dihydrofuran (1 mol eq.), and the complexes 9-12 (3 mol %) in degassed benzene was stirred at 70 °C. The progress of the reaction was monitored by GC. Upon completion, the mixture was filtered through basic alumina (58 mesh, Aldrich) to remove Pd and the products were identified using GCMS. 

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