Potassium r-butoxide

Bases, strong Choline. Claisen s alkali. Lithium (potassium, sodium) amide (ethoxide, hydroxide, methoxide). Lithium nitride. Phenyllithium (potassium, sodium). Potassium r-butoxide. Potassium (sodium) 2-methyl-2-butoxide. Resins Amberlite IRA-dOO. Dowex... 

Color reactions Boric acid (hydroxyquinones). Dimethylaminobenzaldehyde (pyrroles). Ferric chloride (enols, phenols). Haloform test. Phenylhydrazine (Porter-Silber reaction). Sulfoacetic acid (Liebermann-Burchard test). Tetranitromethane (unsaturation). Condensation catalysts /3-Alanine. Ammonium acetate (formate). Ammonium nitrate. Benzyltrimethylammonium chloride. Boric acid. Boron trilluoride. Calcium hydride. Cesium fluoride. Glycine. Ion-exchange resins. Lead oxide. Lithium amide. Mercuric cyanide. 3-Methyl-l-ethyl-2-phosphoiene-l-oxlde. 3-Methyl-1-phenyi-3-phoipholene-1-oxide. Oxalic acid. Perchloric acid. Piperidine. Potaiaium r-butoxIde. Potassium fluoride. Potassium... 

Hydrolysis Cupric sulfate. Hydrobromic acid. Ion-exchange resins. Magnesium sulfate. Morpholine. Nitrosyl chloride. Phosphoric-Acetic acid. Polyphosphoric acid. Potassium r-butoxide. Potassium persulfate. Pyruvic acid (by exchange). Rochelle salt. Silver trifluoro-acetate (gem-dihromides). 

Dehydrohalogenation Alumina, see Sulfur tetrafluoride. Alumina-Potassium hydroxide. Cesium fluoride. l,5-Diazabicyclo[4.3.0]nonene-5. l,4-Diazabicyclo[2.2.2]octane. 1,5-Diazabicyclo[5.4.0]undecene-5. Dimethylaminotrimethylstannane. Dimethyl sulfoxide. Hexamethylphosphoric triamide. Lithium chloride. Lithium dicyclohexylamide. Magnesium oxide. Potassium r-butoxide. Potassium fluoride. Potassium triethylmethoxide. Pyridine, see Nitrosyl chloride. Silver fluoride. Silver nitrate. Sodium amide. Sodium bicarbonate, see Nitryl iodide. Sodium isopropoxide. Triethylamine, see Sulfur dioxide. 

Isomerization Aluminum bromide. Boron trifluoride-Hydrogen fluoride. Dimethyl sulfoxide. Formic acid. N-Lithioethylenediamine. Mercuric acetate. Perchloric acid. Potassium r-butoxide. Potassium hydride. Potassium hydroxide. Zinc dust. 

DEHYDROHALOGENATION Potassium r-butoxide. Potassium hydroxide. Sodium amide. Tetrakis(triphenylphosphine)palladium(0). 

Rate differences observed between the same bromophenylcarbene (241) when prepared by two different routes, diazirine photolysis and the reaction of benzylidene dibromide with potassium r-butoxide, vanish when a crown ether is added to the basic solution in the latter experiment. In this case the complexing potassium bromide is taken over by the crown ether, and selectivity towards alkenes reaches the values of the photolytic runs (74JA5632). 

NO BF )" have also been used to cleave amides. Since only tertiary amides are cleaved by potassium r-butoxide (eq. 6), this method can be used to effect selective cleavage of tertiary amides in the presence of primary or secondary amides. " (Esters, however, are cleaved by similar conditions.) Photolytic cleavage of nitro amides (eq. 7) is discussed in a review. ... 

The first synthesis of 18-crown-6 was reported by Pedersen in his first full paper on erowns . The method used was potassium r-butoxide catalyzed cyclization of hexa-ethlyene glycol monochloride in 1,2-dimethox ye thane, as shown in Eq. (3.7), below. Unfortunately, the yield by this approach was only 1.8%. ... 

With higher homologs e.g., propynyl, butynyl), 3j5-hydroxyandrost-5-en-17-one does not react well with the alkyne and potassium r-butoxide, or with the lithium alkyne in tetrahydrofuran. However, satisfactory results are obtained by use of the alkynylmagnesium bromide in tetrahydrofuran, ... 

The ratio of products 15 and 16 is dependent on the structures, base, and the solvent. The kinetics of the reaction is likewise dependant on the structures and conditions of the reaction. Thus addition or cyclization can be the rate-determining step. In a particularly noteworthy study by Zimmerman and Ahramjian, it was reported that when both diastereomers of 20 were treated individually with potassium r-butoxide only as-epoxy propionate 21 was isolated. It is postulated that the cyclization is the rate-limiting step. Thus, for these substrates, the retro-aldolization/aldolization step reversible. ... 

The classical Michael reaction is carried out in a protic organic solvent—e.g. an alcohol—by use of an alkoxide as base—e.g. potassium r-butoxide or sodium ethoxide. 

Formation of the excited amide anion of coelenteramide as the light emitter in the luminescence reaction of coelenterazine was experimentally supported by the experiment of Hori et al. (1973a), in which 2-methyl analogue of coelenterazine was used as the model compound. The summary of their work is as follows In the presence of oxygen, la and lb in DMF emitted bright blue luminescence (Amax 480 and 470 nm, respectively), and produced the reaction products Ha and lib, respectively. The fluorescence emission of lib (Amax 470 nm) and that of the spent chemiluminescence reaction of lb, both in DMF plus a base (potassium r-butoxide), were identical to the chemiluminescence emission of lb in DMF. The fluorescence emission of Ha... 

Hindered lithium dialkylamides can generate aryl-substituted carbenes from benzyl halides.162 Reaction of a,a-dichlorotoluene or a,a-dibromotoluene with potassium r-butoxide in the presence of 18-crown-6 generates the corresponding a-halophenylcarbene.163 The relative reactivity data for carbenes generated under these latter conditions suggest that they are free. The potassium cation would be expected to be strongly solvated by the crown ether and it is evidently not involved in the carbene-generating step. 

The cyanides 246, obtained from aldehydes R CHO (R1 = alkyl, Ph or PhCH=CH), amines HNR2R3 (aniline or morpholine etc.) and potassium cyanide undergo autoxidation in the presence of potassium r-butoxide to give amides (equation 89)259. 

On reacting with potassium r-butoxide in DMF at 110°C enaminoketones 148 rearrange into acylaminoimidazoles 149 (72TL4959 74T3859 ... 

Singlet dichlorocarbene (generated from chloroform by the action of a strong base, such as potassium r r/-butoxide, KOCMe3), reacts with the anion of pyrrole to give an adduct, which then ring expands to give 3-chloropyridine (Scheme 6.11). 

N-alkylation and N-acylation of piperazine-2,5-diones are quite common and have been routinely employed in several synthetic sequences (see Section IV,C). Such operations have also been performed as measures for the temporary protection of the nitrogen during further synthetic maneuvers in other parts of the molecule. Three different alkyl groups have been employed as such protecting groups. Kishi has used the methoxymethyl group for N-protection (potassium r-butoxide, chloro-methyl methyl ether 0°C, 75% yield). Deprotection was achieved by cone. HCl-ethanol at reflux temperature (81T2045). 

Aliphatic aldehydes react to form monoalkylidene derivatives only in presence of potassium r-butoxide. A mechanism has been postulated that also explains the observed N-deacetylation during the formation of the product. The essential step in this is the intramolecular N - O acetyl migration in the initially formed aldol. Subsequent protonation and elimination of the acetoxy group lead to the product (Scheme 26). 

Under conditions similar to those already outlined, stable aziridin imine derivatives, e.g. (422) and (423), can be prepared in excellent yields (70-80%) by treating the appropriate a-bromoamidines (easily accessible from the amide precursor) with potassium r-butoxide in ether (70AG(E)381>. At low temperatures the elimination proceeds with high regio- and stereo-selectivity at -40 °C (421) yields predominantly (422). 

Cleavage of N—N by potassium r-butoxide to give amidine (164) was observed with diaziridine (134). This is the only known analog of the generally observed acid amide formation from oxaziridines (74JPR999). 

The step 1 product (0.004 mol) and potassium r-butoxide (0.008 mol) were heated to 110°C in a solvent mixture of 25 ml DMAc and 10 ml hexane overnight in a flask containing a Dean-Stark apparatus. After hexane was removed, the mixture was cooled to ambient temperature and treated with trans-l,4-dibromo-2-butene (0.004 mol) and then stirred at ambient temperature for 48 hours. The mixture was then poured into 800 ml of water and a white solid isolated that was air dried and the product isolated in 91% yield. 

Fluoro-l-haloalka-l,3-dienes are prepared in a similar manner by treatment of substituted 2,2-(dihalocyclopropyl)methanols with a hydrogen fluoride/pyridine/diisopropylamine/ sodium fluoride system to give compound 2, followed by dehydrohalogenation with potassium /< r/-butoxide.80... 

Bromomelhylenetriphenylphosphorane, (C6Hb)3P=CHBr (1). Mol. wt. 355.23. The phosphorane can be generated in situ by treatment of bromomethyltriphenyl-phosphonium bromide with potassium r-butoxide in THF at -78°. 

Alkynes. Alkynes are obtained by bisdehydrohalogenation of n c-1,2-dlhromides or gem-dichlorides with solid potassium r-butoxide in petroleum ether in the presence of 0.1 mole % of 18-crown-6. Dichlorides obtained from methyl ketones are converted into I-alkynes only if the 3-position is blocked. Alkynes arc also formed from (F.)-haloalkenes bv. wt-elimination. Yields of alkynes are >80% for the most part. 

The indolizine derivatives (57) and (58) were obtained from a reaction of indolizines with the a-oxohydroximoyl chloride (59) in the presence of triethylamine. It has been assumed that (59) is first converted into a nitrile oxide which is the effective reagent. Cyclization of the 3-(2-oxohydroximyl)indolizines (58) to yield the [2.3.3]cyclazine derivatives (60) was brought about by treatment with potassium r-butoxide (81JCS(P1)3150). 

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