Potassium tert butoxide, solution

Di4ert-butoxypyrimidine (2). Uracil (1) was reacted with phosphorus asy-chloride to give 2,4-dichloropyrimidine (4) (9). Potassium (0.78 g, 20 mmol) was added to room temperature, and the mbdure was stirred under reflux for 1 hour. After the reaction, the precipitated KG was removed filtration, and the solvent was removed by evaporation. The residue was dissolved in diethyl ether, and washed with 30% aqueous KOH and dried over sodium sulfate. After evaporation of the solvent, the product was obtained by distillation under reduced pressure. Yield 1.1 g (49%). IR 1580 and 1155 on H-NMR (CDGj, TMS, 8) 1.4 (18H, s), 6.0 (IH, d), and 7.9 (IH, d). 

Illustrative Procedure 2 Poly(iminocarbonates) by Solution Polymerization (46) Under argon, 1 g of a diphenol and an exact stoichiometric equivalent of a dicyanate were dissolved in 5 ml of freshly distilled THF. 1 mol% of potassium tert-butoxide was added, and the reaction was stirred for 4 hr at room temperature. Thereafter, the poly(iminocarbonate) was precipitated as a gumUke material by the addition of acetone. The crude poly(iminocarbonate) can be purified by extensive washings with an excess of acetone. The molecular weight (in chloroform, relative to polystyrene standards by GPC) is typically in the range of 50,000-80,000. 

It is not satisfactory to employ 1,2-diaminoethane in place of 1,3-diaminopropane. The reagent is not as stable addition of potassium tert-butoxide results in the immediate formation of a deep purple solution. Isomerizations proceed to completion, but yields are somewhat reduced (by about lOX in the case of the rearrangement of 2- to 9-decyn-l-ol). 

The product of the absorption of 3 mmoles of oxygen by a solution of 3 mmoles of diphenylmethane and 15 mmoles of potassium tert-butoxide in 20 ml. of DMSO (80% )-terf-butyl alcohol (20%) was poured into water. Upon standing, colorless crystals of benzhydrol (m.p. 64°C.) formed which could be recovered in 75% yield by filtration. Complete oxidation of the diphenylmethane gave an oxidate which after... 

Figure 7. First derivative ESR spectra of radical anions observed in dimethyl sulfoxide solutions of potassium tert-butoxide. Top, autoxidation product of diphenylamine. No signal was observed in the absence of oxygen. Middle, autoxidation of 4-hydroxy-diphenylamine. Bottom, spontaneous reduction product of mono-anil of p-benzoquinone.

Anthrone did not react with DMSO under the reaction conditions. However, 9,10-anthraquinone (2 mmoles) in 25 ml. of DMSO (80%)-terf-butyl alcohol (20% ) containing potassium tert-butoxide (4 mmoles) gave a deep red solution at 25°C., from which 60% of the adduct could be isolated after 1 hour and 88% after 3 hours. This adduct was isolated from the oxidate of 9,10-dihydroanthracene (after hydrolysis, acidification, and filtrations of anthracene) by extraction of the aqueous filtrate by chloroform. Xanthone and thioxanthone failed to form isoluble adducts with DMSO in basic solution. 

Oxidation of Potassium Peroxide. Determination of Potassium Superoxide. Potassium peroxide was prepared by the addition of a tert-butyl alcohol solution of 90% hydrogen peroxide to potassium tert-butoxide in DMSO or tert-butyl alcohol. Oxygen absorption was followed in the standard manner (20). Analysis of solid precipitates for potassium superoxide followed exactly the method of Seyb and Kleinberg (23). Potassium superoxide formed in the oxidation of benzhydrol was determined in a 15-ml. aliquot of the oxidation solution. To this aliquot 10 ml. of diethyl phthlate was added to prevent freezing of the solution. The mixture was cooled to 0°C., and 10 ml. of acetic acid-diethyl phthlate (4 to 1) added over a period of 30 minutes with stirring. The volume of the evolved oxygen was measured. 

By using potassium tert-butoxide in THF, the system is essentially represented by the living ring-chain equilibrium and the oligomers, isolated and identified to be cyclic, reach equilibrium distribution shortly after the introduction of the initiator solution. 

In the anionic polymerization of 6-caprolactone in THF with potassium tert-butoxide, monomer consumption is very fast and monomer could not be detected in any appreciable amount in the equilibrated mixture obtained after several minutes from the initiation. Upon terminating the reaction at 6 seconds after the introduction of the initiator solution, 6% monomer remained unreacted accompanied with polymers (68%) and oligomers (26%). 

Potassium tert. butoxide, 920, 921 Potassium -butyl xanthate, 499 Potassium ethyl xanthate, 496,499 Potassium hypochlorite solution, 461 Potassium iodide - iodine reagent, 1069 Prileschajew epoxidation reaction, 893J, 894... 

Triazenes have been prepared by the treatment of resin-bound aromatic diazonium salts with secondary amines (Figure 3.27). Regeneration of the amine can be effected by mild acidolysis (Entry 1, Table 3.23). Triazenes have been shown to be stable towards bases such as TBAF, potassium hydroxide, or potassium tert-butoxide [454], and under the conditions of the Heck reaction [455]. Primary amines cannot be linked to supports as triazenes because treatment of triazenes such as R-HN-N=N-Ar-Pol with acid leads to the release of aliphatic diazonium salts into solution [373]. Triazenes derived from primary amines can, however, be used for the preparation of amides and ureas (see Section 3.3.4),... 

Treatment of methyl sulfoxide solutions of D-mannose or other sugar phenylhydrazones or melibiose phenylosazone with potassium tert-butoxide and a trace of oxygen at room temperature showed no evidence of the paramagnetic species characteristic of glyoxal bis(phenylhydra-... 

Guanidine Resin (23). A suspension of Merrifield resin (5 g, 1.7 mmol Cl/g resin) in DMF (100 ml) was treated with guanidine hydrochloride (5 g) and a solution (1 M) of potassium tert-butoxide in THF (50 ml). The resulting reaction mixture was heated at 90° for 24 h. Upon cooling, the resulting resin was filtered and washed with DMF/DBU (7 3), DMF, di-oxane, water, THF, and ethyl ether. The resin thus produced was dried under vacuum at RT overnight. 

This procedure illustrates a recently published, simple, general method for the synthesis of conjugated dienes from olefins. The scope of the reaction is shown in Table I.5 In most of these examples hydrogen bromide. .elimination can be effected by stirring a solution of the olefin-bromo-methanesulfonyl bromide adduct in methylene chloride with one equivalent of triethylamine at room temperature. Only two equivalents of the more costly potassium tert-butoxide are then needed in the second elimination step the yields using the two-base procedure are generally superior to that obtained using only potassium tert-butoxide. 

C. 1,2-Dimethylenecyelohexane. An oven-dried, 1-L, three-necked, round-bottomed flask equipped with a mechanical stirrer, pressure-equalized dropping funnel, and a stopper is charged with potassium tert-butoxide (59.5 g, 0.53 mol) (Note 12) dissolved in tert-butyl alcohol-tetrahydrofuran (9 1, 400 mL total) (Note 13) and cooled in ice. A solution of l-bromo-l-methyl-2-(bromomethylsulfonyl)cyclohexane (54.0 g, 0.16 mol) in tert-butyl alcohol-tetrahydrofuran (9 1, 100 mL) (Note 14) is added dropwise over a 1-hr... 

To a solution of 2-(2-(3(S)-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)-3-hydroxypropyl)phenyl)-2-propanol in THF was dissolved in THF (1 mL) and DMF (1 mL) at -40°C was added diisopropylethylamine (2.2 mmol) and then methanesulfonyl chloride (2.2 mmol). The mixture was stirred 2 hours with slow warming to -30°C. The methyl l-(thiomethyl)cyclopropaneacetate (2.3 mmol) was added to the cloudy reaction mixture followed by dropwise addition of potassium tert-butoxide/THF solution (4.4 mmol). The reaction mixture was stirred at -30°C for 3.5 hours before quenching it with 25% aq NH40Ac. Extraction with EtOAc, washing the organic layer with brine and evaporation of the solvents left a residue that was purified by flash chromatography (5%-10% EtOAc in toluene) giving 658 mg (53%) of methyl l ((((R) (3 (2-(7-chloro-2-quinolinyl)ethenyl)phenyl)-3-(2-(2-hydroxy-2-propyl)phenyl)propyl)thio)methyl)cyclopropaneacetate. 

A solution of 2.0 g (6.9 mMol) of 2-n-propyl-5-(l-methylbenzimidazol-2-yl)-benzimidazole and 0.91 g (7.5 mmol) of potassium tert-butoxide in 50 ml of dimethylsulfoxide is stirred for 90 min at room temperature, then 2.6 g (7.5 mMol) of tert-butyl 4 -bromomethyl-biphenyl-2-carboxylate are added and the mixture is stirred for a further 15 h at room temperature. The mixture is then poured onto 300 ml of water and extracted three times with 50 ml of ethyl acetate. The crude product obtained after evaporation of the organic phase is purified by column chromatography (300 g silica gel eluant methylene chloride/methanol = 30 1). In this way, 2.7 g (70%) of an isomer mixture are obtained (by NMR spectroscopy), contains about 1.18 g of tert-butyl-4 -[(2-n-propyl-5-(l-methylbenzimidazol-2-yl)-benzimidazol-l-yl)-methyl]biphenyl-2-carboxylate and about 1.52 g of tert-butyl 4 -[(2-n-propyl-6-(l-methylbenzimidazol-2-yl)-benzimidazol-l-yl)-methyl]biphenyl-2-carboxylate). 

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