Functional group in organic chemistry

Alkenes are hydrocarbons that contain a carbon-carbon double bond. A carbon-carbon double bond is both an important structural unit and an important functional group in organic chemistry. The shape of an organic molecule is influenced by the presence of this bond, and the double bond is the site of most of the chemical reactions that alkenes undergo. Some representative alkenes include isobutylene (an industrial chemical), a-pinene (a fragrant liquid obtained from pine trees), and famesene (a naturally occuning alkene with three double bonds). 

The series The Chemistry of Functional Groups was originally planned to cover in each volume all aspects of the chemistry of one of the important functional groups in organic chemistry. The emphasis is laid on the preparation, properties and reactions of the functional group treated and on the effects which it exerts both in the immediate vicinity of the group in question and in the whole molecule. 

The final part is devoted to a survey of molecular properties of special interest to the medicinal chemist. The Theory of Atoms in Molecules by R. F.W. Bader et al., presented in Chapter 7, enables the quantitative use of chemical concepts, for example those of the functional group in organic chemistry or molecular similarity in medicinal chemistry, for prediction and understanding of chemical processes. This contribution also discusses possible applications of the theory to QSAR. Another important property that can be derived by use of QC calculations is the molecular electrostatic potential. J.S. Murray and P. Politzer describe the use of this property for description of noncovalent interactions between ligand and receptor, and the design of new compounds with specific features (Chapter 8). In Chapter 9, H.D. and M. Holtje describe the use of QC methods to parameterize force-field parameters, and applications to a pharmacophore search of enzyme inhibitors. The authors also show the use of QC methods for investigation of charge-transfer complexes. 

TABLE 2.1. Classical functional groups in organic chemistry... 

The alcohol functional group is a very important functional group in organic chemistry. Not only do many important compounds and pharmaceuticals contain the alcohol group, but the alcohol group can be prepared from many other... 

Some of the more common functional groups in organic chemistry are as follows ... 

The C—O double bond is the most important functional group in organic chemistry. It is present in aldehydes, ketones, acids, esters, amides, and so on. We shall spend Chapters 5-10 discussing its chemistry so it is important that you understand its electronic structure. As in alkenes, the two atoms that make up this double bond are sp2 hybridized. The carbon atom uses all three sp2 orbitals for overlap with other orbitals to form o bonds, blit the oxygen uses only one for overlap with another orbital (the sp2 orbitals on the carbon atom) to form a O bond. However, the other two sp2 orbitals are not vacant—they contain the oxygen s two lone pairs. A p orbital from the carbon and one from the oxygen make up the n bond which also contains two electrons. 

In this chapter and Chapter 14 we shall look at some more reactions of the carbonyl group—and revisit some of the ones we touched on in Chapter 6. It is a tribute to the importance of this functional group in organic chemistry that we have devoted four chapters of this book to its reactions. Just like the reactions in Chapters 6 and 9, the reactions in Chapters 12 and 14 all involve attack of a nucleophile on a carbonyl group. The difference will be that this step is followed by other mechanistic steps, which means that the overall reactions are not just additions but also substitutions. 

Be able to distinguish between the various functional groups in organic chemistry which contain oxygen, nitrogen, and double and triple bonds. 

Multiple bonds are important functional groups in organic chemistry for several reasons. The n-bonds are rich in electron density and are polarizable hence, multiple bonds are a point of reactivity towards electrophiles. The n-bonds may also be dis-... 

Chapters 20 through 24 of this text discuss carbonyl compounds—aldehydes, ketones, acid halides, esters, amides, and carboxylic acids. The carbonyl group is perhaps the most important Functional group in organic chemistry, because its electron-deficient carbon and easily broken 7t bond make it susceptible to a wide variety of useful reactions. 

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