Functional groups, reactions for

Thionyl chloride and phosphorus tribromide are specialized reagents used to bring about particular functional group transformations For this reason we won t present the mechanisms by which they convert alcohols to alkyl halides but instead will limit our selves to those mechanisms that have broad applicability and enhance our knowledge of fundamental principles In those instances you will find that a mechanistic understand mg IS of great help m organizing the reaction types of organic chemistry... 

Figure 6. Sketch of expected variation of the initial (c0) and residual (cr) concentration of functional groups, reaction conversion , and the ratio ve/Te in end-linked networks as a function of molecular weight of elastomer component M. For discussion see text.

The functional groups used for click chemistry conjugations are completely unreactive toward biological molecules and virtually free of side reactions, which otherwise would cause reagent... 

If the foreign molecule already possesses a functional group suitable for a phase 2 reaction, a phase 1 reaction will be unnecessary. Thus, if phenol is administered to an animal, then it may immediately undergo a phase 2 reaction, such as conjugation with sulfate. Alternatively it may undergo another phase 1 type of reaction. The major types of reactions are shown in Table 4.2. 

Generally, therefore, the function of phase 1 reactions is to modify the structure of a xenobiotic so as to introduce a functional group suitable for conjugation with glucuronic acid, sulfate, or some other highly polar moiety, so making the entire molecule water soluble. 

The calculation of the gel point or the molecular weight distribution becomes difficult if the functional groups in monomers differ in reactivity (26, 27). Polycondensation of glycerol with symmetrical dibasic acid or of an unsymmetrical dibasic acid with symmetrical tribasic alcohol may serve as examples. The reaction probabilities of various functional group , necessary for the calculation of molecular weight distributions and gel points, have to be determined either from complete chemical analysis or from the kinetics of the respective reactions. 

A unit in the first generation, or in any higher generation, has only (f- 1) functional groups available for further reaction, thus... 

Aldol reactions provide a valuable synthetic method for forming carbon-carbon bonds. They can be adapted to extend the length of a carbon chain, to form cyclic compounds, and to provide intermediates that can be transformed into more useful materials. An important feature of these intermediates is that functional groups useful for later reactions are located close to or on the carbons of the newly formed C-C bond. There is an almost bewildering number of variations on the aldol reaction and we shall not mention all of them. The main thing to recognize in all of these reactions is that the acceptor molecule always is a carbonyl compound, best an aldehyde, sometimes a ketone, even an ester (see Section 18-8E). The donor molecule is some type of carbanion usually, but not always, an enolate anion. However, any substance that has a... 

See the appropriate functional group Y for conjugate addition reactions. 

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