How Are Carboxyl Groups Reduced

The carboxyl group is one of the organic functional groups that is most resistant to reduction. It is not affected by catalytic reduction (H2/M) under conditions that easily reduce aldehydes and ketones to alcohols and that reduce alkenes to alkanes. The most common reagent for the reduction of a carboxylic acid to a primary alcohol is the very powerful reducing agent lithium aluminum hydride (Section 12.10). 

The first drug developed for widespread use was aspirin, today s most common pain reliever. Americans alone consume approximately 80 billion tablets of aspirin a year The story of the development of this modern pain reliever goes back more than 2,000 years In 400 b.c.e., the Greek physician Hippocrates recommended chewing bark of the willow tree to alleviate the pain of childbirth and to treat eye infections. 

The active component of willow bark was found to be salicin, a compound composed of salicyl alcohol joined to a unit of j3-D-glucose (Section 17.2). Hydrolysis of salicin in aqueous acid gives salicyl alcohol, which can then be oxidized to salicylic acid, an even more effective reliever of pain, fever, and inflammation than salicin and one without its extremely bitter taste  

Unfortunately, patients quickly recognized salicylic acid s major side effect It causes severe irritation of the mucous membrane lining the stomach. 

In the search for less irritating, but still effective, derivatives of salicylic acid, chemists at the Bayer division of I. G. Farben in Germany prepared acetyl-salicylic acid in 1883 and gave it the name aspirin, a word derived from the German spirsaure (salicylic acid), with the initial a for the acetyl group  

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In the discussion of translation, the amino acids were taken for granted. In this chapter we must discuss several aspects of their biosynthesis. Their name is derived from the fact that in all frequently occurring amino acids an amino group is found in the a-position to a carboxyl group. We shall concern ourselves first with the origin of this reduced N and then see how it is transferred to the C skeleton, i.e. how the amino acids are formed. 

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