Amide weak basic properties

Amides have very weak basic properties and protonation is possible either on the oxygen (A) or on the nitrogen (B).82 83... 

Acrylamide copolymer POLYSWELL was applied as a lydrophilic filler. The acrylamide copolymer is a white grannlar material, density is 0.8-1.0 g/cm, water-swellable to form a polymer gel. In solutions the amide group shows weak-basic properties at the expense of the lone election pair on the nitrogen atom that is the reason of nonchemical interaction of the polymer with water. 

Acid amides have weakly amphoteric properties, and thus give salts such as CjHsCONHj.HCl with strong acids, and salts of the type C HsCONHNa with strong bases. These compounds have to be prepared at low temperatures to avoid hydrolysis, and are difficult to isolate. The mercury derivatives can, however, usually be readily prepared, because mercuric oxide is too feebly basic to cause hydrolysis of the amide, and the heavy mercuric derivatives crystallise well. 

Acrylamide, C H NO, is an interesting difiinctional monomer containing a reactive electron-deficient double bond and an amide group, and it undergoes reactions typical of those two functionalities. It exhibits both weak acidic and basic properties. The electron withdrawing carboxamide group activates the double bond, which consequendy reacts readily with nucleophilic reagents, eg, by addition. 

Itraconazole (Sporanox, 13.11) is an approved antifungal (Figure 13.5). The drug has a log P value of 6.5, so its very low aqueous solubility is no surprise. Early efforts to improve the properties of itraconazole focused on making an acid salt. Because of the very weak basicity of all the nitrogens in itraconazole, the idea of an acid salt was soon abandoned. Cocrystals were then explored. A library of amides and acids were... 

Many nonaqueous solvents have been proposed as suitable media for the determination of substances with weakly acidic properties or of their mixtures, but only some of them have found widespread use, because of their suitable characteristics and practical advantages. Thus, liquid ammonia and ethylene diamine (1,2-diaminoethane) show unsuitable physical characteristics and high basicity and absorb atmospheric carbon dioxide. Dimethyl sulfoxide and pyridine are unpleasant to use and dangerous in everyday work, although a series of chemical indicators have been established for use in these two solvents. On the other hand, N,N-dimethylform-amide (DMF) is a very popular solvent for the titration of acids and mixtures of acids, and isopropyl and -butyl alcohols show a large resolution of acid strength and allow to successfully solve acid mixtures. 

Alkanoylglycamine surfactants are interesting materials having distinctive properties. Their phase behavior suggests that they are more hydrophilic than typical polyoxyethylene surfaetants, but less hydrophilic than other subclasses of nonionic surfactants (semipolar, zwitterionic). They are far less hydrophilic than ionic surfactants. The eompounds are weakly basic—the pKa of protonated dialkyl amides is about 1—so they remain unprotonated and nonionic within the usual pH range. As a result, they do not display the numerous complexities typieally found in ionic compounds. 

Amides can behave as a weak acid or a weak base. They are less basic than amines due to the electron withdrawing properties of the carbonyl- Amides are hydrolysed by either strong acids or strong bases. 

Donor numbers of various solvents are listed in Table 3. The values range between 0 and about 60 kcal/mole. Polar solvents such as nitromethane are very weak donors. Solvents such as acetonitrile and propylenecarbonate are moderately strong donors. Ketone, ester, and ether solvents show medium donor properties. Amides and sulfones are strongly basic solvents with donor numbers 25 to 30, and aliphatic amines are very strong donors. 

To verify that this is purely based on the hydrogen-bond strength of the donors and acceptors, it is important to establish whether the balance between an aromatic N-heterocycle and an amide can be reversed by lowering sufficiently the hydrogen-bond accepting property of the aromatic nitrogen atom. With this in mind, we synthesized a set of ditopic supramolecular reagents that combined an amide moiety with a very weak base, pyrazole. The idea was that if the basicity of the... 

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