Carbon compounds amides

The formation of the above anions ("enolate type) depend on equilibria between the carbon compounds, the base, and the solvent. To ensure a substantial concentration of the anionic synthons in solution the pA" of both the conjugated acid of the base and of the solvent must be higher than the pAT -value of the carbon compound. Alkali hydroxides in water (p/T, 16), alkoxides in the corresponding alcohols (pAT, 20), sodium amide in liquid ammonia (pATj 35), dimsyl sodium in dimethyl sulfoxide (pAT, = 35), sodium hydride, lithium amides, or lithium alkyls in ether or hydrocarbon solvents (pAT, > 40) are common combinations used in synthesis. Sometimes the bases (e.g. methoxides, amides, lithium alkyls) react as nucleophiles, in other words they do not abstract a proton, but their anion undergoes addition and substitution reactions with the carbon compound. If such is the case, sterically hindered bases are employed. A few examples are given below (H.O. House, 1972 I. Kuwajima, 1976). 

Electronically, we find that strongly polarized acyl compounds react more readily than less polar ones. Thus, acid chlorides are the most reactive because the electronegative chlorine atom withdraws electrons from the carbonyl carbon, whereas amides are the least reactive. Although subtle, electrostatic potential maps of various carboxylic add derivatives indicate the differences by the relative blueness on the C-O carbons. Acyl phosphates are hard to place on this scale because they are not used in the laboratory, but in biological systems they appear to be somewhat more reactive than thioesters. 

The reactivity of phosphorus ylides towards carbonyl compounds such as ketones, esters, carbonates and amides has also been explored13. The mechanism shown in... 

Hydrocarbons. Alcohols. Aldehydes. Ketones. Organic sulfur compounds. Hydrated compounds. Carbon acids. Carbon acid amides, urea, and other compounds... 

The third group is water-immiscible organic species with electron donor or acceptor properties, or solvating carriers. They include carbon-oxygen compounds (amides, ethers, ketones) phosphorus-oxygen compounds (tri- -butylphosphate (TBP), dibutyl-phosphate (DBP) or-phosphonate (DBBP) phosphine oxides (tri- -octylphosphine oxide (TOPO) phosphine sulfides (Cyanex 471) alkyl sulfides (dihexyl, diheptyl sulfides) nitrogen containing compounds (CLX 50), and so on [1-7, 81, 83]. All of them are known as selective extractants, but few of them are tested as carriers in LM processes. 

A number of modern industrial processes are based on the catalytic carbonyl at 1 on of organic substrates by carbon monoxide. ll In contrast, the application of carbon monoxide as reductant in organic synthesis is confined to relatively few exampl es. 2l In recent years the catalytic carbonyl at I on of nitro compounds has become a ery intense field of research. This is due to the fact that 3 series of industrially important compounds can be obtained - om nitro compounds and carbon monoxide in a single step azo compounds, amides, amines, oximes, ureas, urethanes and isocyanates [ 3] and indoles. Ureas and urethanes are important final products and intermediates in the synthesis of ert ll eps and pesticides. On the other hand mono and di-1 socyanates are very important intermed 1 a es in the manu-i-acture of pesticides, polyurethane foam plastics, synthetic leather, adhesives and coatings. 

Another carbon compound has an acidic proton, and the acid-base reaction is quite common. Alkynes (Chapter 5, Section 5.2) are categorized as internal alkynes (R-C=C-R) or terminal alkynes (R-C=C-H). The hydrogen atom of a terminal alkyne is a weak acid (pK of about 25), and strong bases such as sodium amide (NaNH2) remove that proton to give an alkyne anion (R-C=C ). In this reaction, the alkyne anion is the conjugate base of the alkyne, which is a weak acid. Alkyne anions are useful nucleophiles in many reactions (see Section 6.7). 

Structure-AAA relationship of N-phenylacetamide derivatives and aromatic carbonic acid amides has been investigated, cyclic and acyclic signs typical for compounds with pronounced AAA have been recognized. 

Kreutzberger, A. Schroeders, H.H. Antiviral agents. 4. Aromatically substituted carbonic acid amide structure in potentically Virustatic compounds. Arzneimittel-Forsch., 1975 vol 25, N° 7,994-997. 

The conversion of a carbonyl compound by ammonium polysulphide solution into an amide with the same number of carbon atoms is known as the Willgerodt reaction. The procedure has been improved by the addition of about 40 per cent, of dioxan or of pyridine to increase the mutual solubility of the ketone and aqueous ammonium polysulphide the requisite temperature is lowered to about and the yield is generally better. 

The lower members of other homologous series of oxygen compounds— the acids, aldehydes, ketones, anhydrides, ethers and esters—have approximately the same limits of solubility as the alcohols and substitution and branching of the carbon chain has a similar influence. For the amines (primary, secondary and tertiary), the limit of solubility is about C whilst for the amides and nitriles it is about C4. 

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