Carbonyl compound , acidity kinds

Most later studies carried out by Raffi et al."-un- 02 on -/-irradiation of starch of various origins at 0.60 and 6.2 kGy/h under either air or nitrogen show that differences in total composition and yield of carbonyl compounds, acidity, hydrogen peroxide, and observed ESR spectra may be extrapolated from one starch to another, despite the fact that particular relationships are nonlinear (Figs. 18-21). The dispersibility of starch plays an important role in this kind of sensitivity, as... 

Carbonyl compounds are everywhere. Most biological molecules contain carbonyl groups, as do most pharmaceutical agents and many of the synthetic chemicals that touch our everyday lives. Citric acid, found in lemons and oranges acetaminophen, the active ingredient in many over-the-counter headache remedies and Dacron, the polyester material used in clothing, all contain different kinds of carbonyl groups. 

Judging from the following electrostatic potential maps, which kind of carbonyl compound has the more electrophilic carbonyl carbon atom, a ketone or an acid chloride Which has the more nucleophilic carbonyl oxygen atom Explain. 

Enamines behave in much the same way as enolate ions and enter into many of the same kinds of reactions. In the Stork reaction, for example, an enamine adds to an aqQ-unsaturated carbonyl acceptor in a Michael-like process. The initial product is then hydrolyzed by aqueous acid (Section 19.8) to yield a 1,5-dicarbonyi compound. The overall reaction is thus a three-step sequence of (11 enamine formation from a ketone, (2) Michael addition to an a,j3-unsaturated carbonyl compound, and (3) enamine hydrolysis back to a ketone. 

Step 1 of Figure 29.3 Introduction of a Double Bond The /3-oxidation pathway begins when a fait)7 acid forms a thioester with coenzyme A to give a fatty acyl Co A. Two hydrogen atoms are then removed from C2 and C3 of the fatty acyl CoA by one of a family of acyl-CoA dehydrogenases to yield an a,/3-unsaturated acyl CoA. This kind of oxidation—the introduction of a conjugated double bond into a carbonyl compound—occurs frequently jn biochemical pathways and usually involves the coenzyme flavin adenine dinucleotide (FAD). Reduced FADH2 is the by-product. 

Compared to carboxylic and carbonic acid derivatives, the less highly oxidized carbonyl compounds such as aldehydes and ketones are not so widespread in nature. That is not to say that they are unimportant. To the contrary. Aldehydes and ketones are of great importance both in biological chemistry and in synthetic organic chemistry. However, the high reactivity of the carbonyl group in these compounds enables them to function more as intermediates in metabolism or in synthesis than as end products. This fact will become evident as we discuss the chemistry of aldehydes and ketones. Especially important are the addition reactions of carbonyl groups, and this chapter is mostly concerned with this kind of reaction of aldehydes and ketones. 

The Cannizzaro reaction, that is, the base-catalysed disproportionation of a carbonyl compound to an alcohol and a carboxylic acid, has gained some importance as an economically viable alternative to the reduction with borohydrides. However, the reaction is restricted to carbonyl compounds without any a-hydrogen, which do not undergo competing aldol reactions. Thus, mainly aromatic aldehydes are used for this kind of transformation. The protocols developed for microwave applications typically involve solvent-free conditions using alumina as the solid support. Under these conditions, a significant acceleration of the reaction was achieved. 

The magnesium salt of glycol is thus formed. It yields a glycol with the trival name pinacol upon workup with weak acid. Hence, this kind of reductive coupling of carbonyl compounds is called pinacol coupling. 

All kinds of carbonyl compounds can be reduced, including aldehydes, ketones, carboxylic acids, and esters. 

All kinds of carbonyl compounds, including aldehydes, ketones, esters amides, acid anhydrides, and nitriles, enter into condensation reactions, Nature uses these same carbonyl condensation reactions in the biosynthesis of many naturally occurring compounds. 

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