Carbonyl grou

If the carbonyl grou]) in the 3-position of N-methylisatin or tlii-ana])hthencquinone is blocked by formation of an oxime (cf. 112), A -methylation of the oxime group occurs instead of ring expansion on reaction with diazomethane. In methanol, thianaphthenequinone oxime iV-mcthyl ether (113) then undergoes ring opening catalyzed by diazoniethane (113 114). 

The third major reaction of carbonyl compounds, alpha substitution, occurs at the position next to the carbonyl grou —the alpha (q-) ]rosition. This reaction, which takes place with all carbonyl compounds regardless of structure, results in the substitution of an a hydrogen by an electrophile tlirough the formation of an inteianedlate eno or enolate ion ... 

T hese few examples are only an introduction we ll look at several of the major metabolic pathways in much more detail in Chapter 29. Tire bottom line is that you haven t seen the end of carbonyl-grou[r chemistry. A solid grasp of carbonyl-group reactions is crucial to an understanding of biochemistry. 

Figure 2.57 Ammoximation of carbonyl grou ps with TS-1. Source adapted from Corma ...

An aldehyde has a hydrogen atom bonded to the carbon atom of a carbonyl grou p (Section 21.11) ... 

Nucleophilic acyl substitution reaction (Section 21.2) A reaction in which a nucleophile attacks a carbonyl compound and substitutes for a leaving grou[) bonded to the carbonyl carbon. 

The reduction of macrosalhine thiocyanate with sodium and methanol gives an amorphous tertiary base which contains no carbonyl groups, hemiacetal grou[)s, or olefinic double bonds. The properties of this product, including its mass spectrum, are in accord with the constitution LI. 

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