Butoxide, tert

This isomerization, which must proceed through a 1,2,3-trienylanine, is not "contra-thermodynamic", since with a catalytic amount of potassium tert.-butoxide the same result is obtained. Enyne ethers, H2C=CH-CsC-0R, undergo a similar conversion into HCeC-CH=CH-OR upon interaction with alkali metal amides in liquid NH3, followed by hydrolysis . Enyne sulphides, H2C=CH-CsC-SR, and the hydrocarbons H2C=CH-CsC-R (R = or phenyl) give only tars or polymeric products under... 

Similarly sodium methoxide (NaOCHj) is a suitable base and is used m methyl alco hoi Potassium hydroxide m ethyl alcohol is another base-solvent combination often employed m the dehydrohalogenation of alkyl halides Potassium tert butoxide [K0C(CH3)3] is the preferred base when the alkyl halide is primary it is used m either tert butyl alcohol or dimethyl sulfoxide as solvent... 

Use curved arrows to show the bonding changes in the reaction of CIS 4 tert butylcyclohexyl bromide with potassium tert butoxide Be sure your drawing correctly represents the spatial relationship between the leaving group and the proton that is lost... 

Compound A (C4H10) gives two different monochlondes on photochemical chlorination Treatment of either of these monochlondes with potassium tert butoxide in dimethyl sulfoxide gives the same alkene B (CaHg) as the only product What are the structures of compound A the two monochlondes and alkene B2... 

Compound A (CgHi4) gives three different monochlondes on photochemical chlonnation One of these monochlondes is inert to E2 elimination The other two monochlondes yield the same alkene B (CgHi2) on being heated with potassium tert butoxide in tert butyl alcohol Men tify compound A the three monochlondes and alkene B... 

Compounds A and B are isomers of molecular formula C9Hi9Br Both yield the same alkene C as the exclusive product of elimination on being treated with potassium tert butoxide in dimethyl sulfoxide Hydrogenation of alkene C gives 2 3 3 4 tetramethylpentane What are the structures of compounds A and B and alkene C2... 

If however the base itself is a crowded one such as potassium tert butoxide even pn mary alkyl halides undergo elimination rather than substitution... 

As a practical matter elimination can always be made to occur quantitatively Strong bases especially bulky ones such as tert butoxide ion react even with primary alkyl halides by an E2 process at elevated temperatures The more difficult task is to find condifions fhaf promofe subsfifufion In general fhe besf approach is fo choose condi lions lhal favor fhe 8 2 mechanism—an unhindered subslrale a good nucleophile lhal IS nol slrongly basic and fhe lowesl praclical lemperalure consislenl wilh reasonable reaclion rales... 

Double dehydrohalogenation to form terminal alkynes may also be carried out by heating geminal and vicinal dihalides with potassium tert butoxide m dimethyl sulfoxide... 

Dihalocarbenes are formed when trihalomethanes are treated with a strong base such as potassium tert butoxide The trihalomethyl anion produced on proton abstraction dissociates to a dihalocarbene and a halide anion... 

Potassium tert butoxide reacts with halobenzenes on heating in dimethyl sulfoxide to give ten butyl phenyl ether... 

Difluorododecane is unaffected by sodium methoxide in methanol, but its treatment with potassium tert-butoxide in tetrahydrofuran eliminates hydrogen fluonde stereospecifically rneso and dl compounds give, respectively, ( )- and (2) 6 fluoro 6 dodecene [12] (equation 11)... 

The dichloride 8.21a forms fragile, lamellar crystals with a golden colour. The X-ray structure reveals a layered arrangement of hexameric units formed by linking three ( BuNTeCl2)2 dimers by chloride bridges. The reaction of 8.21a with potassium tert-butoxide yields... 

Alkali-metal thionylimides are prepared by the reaction of McsSiNSO with the appropriate alkali-metal tert-butoxide in THF (Eq. 9.1). The more soluble [(MeaNlsS]" salt has also been reported (Eq. 9.2). ... 

The following preparation is given in U.S. Patent 3,356,573. 17a-Acetoxy-3(3-hydroxy-6-methylpregn-5-en-20-one (1 g), aluminum tert-butoxide (1 g) and p-benzoquinone (6 g) were dissolved in dry benzene (100 ml) and the mixture was heated under reflux for 30 minutes. The reaction mixture was cooled and washed with potassium hydroxide solution until the benzene layer was colorless. The benzene was washed with water, dried and evaporated to dryness under reduced pressure. The residue crystallized from aqueous methanol to give 17a-acetoxy-6-methylpregna-4,6-diene-3,20-dione, needles, MP 214° to 216°C. 

Acetoxolone aluminum salt Aluminum amalgam Dinoprostone Aluminum tert-butoxide Megestrol acetate Aluminum chloride Acebutolol... 

Because the Williamson synthesis is an S 2 reaction, it is subject to all the usual constraints, as discussed in Section 11.2. Primary halides and tosylates work best because competitive E2 elimination can occur with more hindered substrates. Unsymmetrical ethers should therefore be synthesized by reaction between the more hindered alkoxide partner and less hindered halide partner rather than vice versa. For example, terf-butyl methyl ether, a substance used in the 1990s as an octane booster in gasoline, is best prepared by reaction of tert-butoxide ion. with iodomethane rather than by reaction of methoxide ion with 2-chloro-2-methylpropane. 

Exposure of compound 16, a substance that can be obtained in a straightforward manner from glycine, to sodium tert-butoxide furnishes an enolate that undergoes conversion to 8 upon treatment with terf-butyl formate. It was anticipated that the phthalimido and tert-butyl ester protecting groups in 8 could be removed easily and selectively under anhydrous conditions at a later stage in the synthesis. 

The reaction of phthalaldehyde and diethyl oxydiacetate in the presence of potassium tert-butoxide gives, with hydrolysis of the ester function, 3-benzoxepin-2,4-dicarboxylic acid (2a).89 The reaction of the dimethyl ester lb gives dimethyl 3-benzoxepin-2,4-dicarboxylate (2 b) when... 

Hydrogen bromide is eliminated from 10,11-dibromo-l 0,1 l-dihydrodibenz[7>,/]oxepin with potassium tert-butoxide at room temperature to give 10-bromodibenz[i,/]oxepin (17a).160161 When the elimination reaction was performed in boiling toy-butanol the yield increased from 58 to 92%.261 Dehydrohalogenation of 10-chloro-2,3-dimethoxy-10,ll-dihydrodi-benz[/),/]oxepin afforded 2,3-dimethoxydibenz[6,/]oxepin (17b) in 52% yield.162... 

The ketones 1 and 3, or compounds with a similar structure, have been used for the preparation of methoxy derivatives of 1-benzoxepin. In the standard procedure for methylation, the 1-benzoxepinone is deprotonated by potassium tert-butoxide and subsequently reacted with methyl fluorosulfonate at low temperature.16 173 - 175 The yields are generally high. 

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