Strongly basic

C2H3N. Colourless liquid with strong ammoniacal smell b.p. 56 C. Miscible with water and strongly basic. Prepared commercially from 2-aminoelhanol. Pure dry aziridine is comparatively stable but it polymerizes explosively in the presence of traces of water. Carbon dioxide is sufficiently acidic to promote polymerization. 

Protamines. Strongly basic, low mol. wt. proteins which contain high levels of arginine, but no sulphur-containing amino-acids. They are soluble proteins, associated with nucleic acids and are obtained in large quantity from fish spermatozoa. 

As we shall see later, the limitations imposed by most solvents may prevent us from being able to utilise the very strong basic characteristics of some anions. However, at this point it is more useful to consider other factors affecting the strengths of acids. 

Thus, ihe strongly basic oxide ion attacks the weakly acidic SiOj in a molten salt as solvent (p. 187 ... 

This reaction is due to the very strong basic property of the hydride ion H" which behaves as a powerful proton acceptor and is therefore strongly basic, i.e. 

The Claisen condensation is initiated by deprotonation of an ester molecule by sodium ethanolate to give a carbanion that is stabilized, mostly by resonance, as an enolate. This carbanion makes a nucleophilic attack at the partially positively charged carbon atom of the e.ster group, leading to the formation of a C-C bond and the elimination ofan ethanolate ion, This Claisen condensation only proceeds in strongly basic conditions with a pH of about 14. 

In the strongly basic medium, the reactant is the phenoxide ion high nucleophilic activity at the ortho and para positions is provided through the electromeric shifts indicated. The above scheme indicates theorpara substitution is similar. The intermediate o-hydroxybenzal chloride anion (I) may react either with a hydroxide ion or with water to give the anion of salicyl-aldehyde (II), or with phenoxide ion or with phenol to give the anion of the diphenylacetal of salicylaldehyde (III). Both these anions are stable in basic solution. Upon acidification (III) is hydrolysed to salicylaldehyde and phenol this probably accounts for the recovery of much unreacted phenol from the reaction. 

Note 1. A slight excess of phenol was used. With a stoichiometric amount the solution may be too strongly basic, so that the further isomerization will become too fast. 

Nonanedione, another 1,3-difunctional target molecule, may be obtained from the reaction of hexanoyl chloride with acetonide anion (disconnection 1). The 2,4-dioxo substitution pattern, however, is already present in inexpensive, symmetrical acetylacetone (2,4-pentanedione). Disconnection 2 would therefore offer a tempting alternative. A problem arises because of the acidity of protons at C-3 of acetylacetone. This, however, would probably not be a serious obstacle if one produces the dianion with strong base, since the strongly basic terminal carbanion would be a much more reactive nucleophile than the central one (K.G. Hampton, 1973 see p. 9f.). 

Oxindoles can be prepared from Af,p-acylphenylhydrazines by a reaction which is analogous to the Fischer cyclization. This is known as the Brunner reaction. The reaction is typically conducted under strongly basic conditions. For example, heating Af-phenylcyclopentanecarbonylhydrazide with CaO gives a 70% yield of spiro-cyclopentane oxindole[l]. 

With the exception of the nuclear amination of 4-methylthiazole by sodium amide (341, 346) the main reactions of nucleophiles with thiazole and its simple alkyl or aryl derivatives involve the abstraction of a ring or substituent proton by a strongly basic nucleophile followed by the addition of an electrophile to the intermediate. Nucleophilic substitution of halogens is discussed in Chapter V. 

Water can also be a Brpnsted acid donating a proton to a base Sodium amide (NaNH2) for example is a source of the strongly basic amide ion which reacts with water to give ammonia... 

Potassium hydride (KH) is a source of the strongly basic hydride ion ( H ) Using curved arrows to track electron movement write an equation for the reaction of hydride ion with water What is the conjugate acid of hydride lon ... 

Notice too that strongly basic leaving groups are absent from Table 8 8 In gen eral any species that has greater than about 2 for its conjugate acid cannot be a... 

Calcium carbide is the calcium salt of the doubly negative carbide ion (C=C ) Car bide ion is strongly basic and reacts with water to form acetylene... 

Organohthium and organomagnesium compounds are stable species when prepared m suitable solvents such as diethyl ether They are strongly basic however and react instantly with proton donors even as weakly acidic as water and alcohols A proton is transferred from the hydroxyl group to the negatively polarized carbon of the organometallic compound to form a hydrocarbon... 

Sometimes the strongly basic properties of Gngnard reagents can be turned to synthetic advantage A chemist needed samples of butane specifically labeled with deuterium the mass 2 isotope of hydrogen as shown... 

It looks as though all that is needed is to prepare the acetylenic anion then alkylate it with methyl iodide (Section 9 6) There is a complication however The carbonyl group m the starting alkyne will neither tolerate the strongly basic conditions required for anion formation nor survive m a solution containing carbanions Acetyhde ions add to carbonyl... 

The carbon-nitrogen triple bond of nitriles is much less reactive toward nucleophilic addition than is the carbon-oxygen double bond of aldehydes and ketones Strongly basic nucleophiles such as Gngnard reagents however do react with nitriles in a reaction that IS of synthetic value... 

Both CH3CH2CH2C=CH and CH3CH2C=CCH3 can be prepared by alkylation of acety lene The alkyne (CH3)2CHC=CH cannot be prepared by alkylation of acetylene because the required alkyl halide (CH3)2CHBr is secondary and will react with the strongly basic acetylide ion by elimination... 

Anion exchange resins—gel type — Strongly basic- —quaternary ammonium functionality... 

Dowex 1-X2 0.6 0.65 Strongly basic anion exchanger with S-DVB matrix for separation of small peptides, nucleotides, and large metal complexes. Molecular weight exclusion is <2700. 

Dowex 2-X8 1.2 0.75 Strongly basic (but less basic than Dowex 1 type) anion exchanger with S-DVB matrix for deionization of carbohydrates and separation of sugars, sugar alcohols, and glycosides. 

Quaternary ammonium exchangers contain —R4N+ groups which are strongly basic and completely dissociated in the OH form and the anion form. 

The acidity constant for an acid-base indicator was determined by preparing three solutions, each of which has a total indicator concentration of 5.00 X 10- M. The first solution was made strongly acidic with HCl and has an absorbance of 0.250. The second solution was made strongly basic and has an absorbance of 1.40. The pH of the third solution was measured at 2.91, with an absorbance of 0.662. What is the value of K, for the indicator ... 

The addition of alcohols to form the 3-alkoxypropionates is readily carried out with strongly basic catalyst (25). If the alcohol groups are different, ester interchange gives a mixture of products. Anionic polymerization to oligomeric acrylate esters can be obtained with appropriate control of reaction conditions. The 3-aIkoxypropionates can be cleaved in the presence of acid catalysts to generate acrylates (26). Development of transition-metal catalysts for carbonylation of olefins provides routes to both 3-aIkoxypropionates and 3-acryl-oxypropionates (27,28). Hence these are potential intermediates to acrylates from ethylene and carbon monoxide. 

Tazettine (73) has gained notoriety siace, subsequent to its isolation from Sprekeliaformosissima or Narcisus ta tta and proof that it was generated in vivo from haemanthamine [466-75-1] (76), ia accord with biosynthetic dogma (52), more careful work (53) ia which the strongly basic... 

The AsF ion is very stable toward hydrolysis in aqueous solution. It is not hydroly2ed by boiling a strongly basic solution almost to dryness (26), although it is hydroly2ed in sulfuric acid (27) or in boiling perchloric acid (26). The hydrolysis of AsF in concentrated sulfuric acid (27) and in base (28) at 193—222°C is first order in AsF . The hydrolysis of AsF in alkaline solution is slower than either PF or SbF . ... 

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