Amides acid-base chemistry

Acid amide herbicides Acid anhydrides Acid azine dyes Acid-base catalysis Acid-base chemistry Acid Black [1064-48-8]... 

The effect of temperature on the acid base chemistry of the stationary phase can also play a role in separation. Free silanol groups on the stationary phase may exhibit changes in acid base chemistry with temperature [28]. Also, reverse phase columns with amine, amide, or acidic functional groups will be affected by the interaction of the temperature, the ionization state of the stationary phase, the mobile phase acidity, and the ionization state of the solute. Most non-linear van t Hoff plots can be rationalized in these terms, but it is difficult to predict a priori what the effects will be on a given system. Thus, it is important to characterize the system under study if a simple change in temperature produces unexpected effects. 

Preparation of the aikynide anion involves simple Bronsted-Lowry acid-base chemistry. As you have seen (Sections 7.9 and 7.11), the hydrogen of a terminal alkyne is weakly acidic = 25), and with a strong base such as sodium amide it can be removed. The reason for this acidity was explained in Section 3.8A. 

As we saw earlier (Section 17-9), amines also are capable of attacking the carbonyl function. When the carbonyl is that of a carboxylic acid, the product is a carboxylic amide, the last major class of carboxylic acid derivatives. The mechanism is again addition-elimination but is complicated by acid-base chemistry. 

Brown, R.S. (2000). Studies in amide hydrolysis the acid, base and water reactions. In The Amide Linkage. Structural Significance in Chemistry, Biochemistry and Materials Science, Greenberg, A., Breneman, C.M. and Liebman, J.F. (eds), p. 85. John Wiley Sons, Inc., New York... 

The synthesis of a linear precursor peptide of the HSV-a-[Tyr ]-conotoxin chimera (see Note 8) was performed by solid phase methodology on an Applied Biosystems Mod. 431A peptide synthesizer (Applied Biosystems Paris, France). Fmoc-based chemistry was used for the preparation of peptide using Rink-amide resin with 0.43 mmol/g loading. Four equivalents of Fmoc amino acid derivatives and HBTU/HOBt were used for coupling. The following amino acid derivatives were used in the synthesis Fmoc-Cys(Trt)-OH, Fmoc-Gly-OH, Fmoc-Val-OH, Fmoc-Pro-OH, Fmoc-Cys(Acm)-OH, Fmoc-Asn(Trt)-OH, Fmoc-Tyr( Bu)-OH. The synthetic protocol for Fmoc chemistry was as follows ... 

The chemistry behind amino acid analysis is nothing more than acid-catalyzed hydrolysis of amide (peptide) bonds. The peptide is hydrolyzed by heating in 6 M hydrochloric acid for about 24 h to give a solution that contains all the amino acids. This mixture is then separated by ion-exchange chromatography, which separates the amino acids mainly according to their acid-base properties. As the amino acids leave the chromatography column, they are mixed with ninhydrin and the intensity of the ninhydrin... 

---