Alcohols and Ethers
ALCOHOLS AND ETHERS The hydroxyl group is one of the most important functional groups of na- turally occurring organic molecules. All carbohydrates and their derivatives, including nucleic acids, have hydroxyl groups. Some amino acids, most ste- roids, many terpenes, and plant pigments have hydroxyl groups. These sub- stances serve many diverse purposes for the support and maintenance of life. One extreme example is the potent toxin tetrodotoxin, which is isolated from puffer fish and has obvious use for defense against predators. This compound has special biochemical interest, having six different hydroxylic functions arranged on a cagelike structure: tetrodotoxin On the more practical side, vast quantities of simple alcohols - metha- nol, ethanol, 2-propanol, 1-butan01 - and many ethers are made from petro- leum-derived hydrocarbons. These alcohols are widely used as solvents and as intermediates for the synthesis of more complex substances. 15 Alcohols and Ethers The reactions involving the hydrogens of alcoholic OH groups are expected to be similar to those of water, HOH, the simplest hydroxylic com- pound. Alcohols, ROH, can be regarded in this respect as substitution products of water. However, with alcohols we shall be interested not only in reactions that proceed at the 8-H bond but also with processes that result in cleavage of the C-0 bond, or changes in the organic group R. The simple ethers, ROR, do not have 0-H bonds, and most of their reactions are limited to the substituent groups. The chemistry of ethers, there- fore, is less varied than that of alcohols. This fact is turned to advantage in the widespread use of ethers as solvents for a variety of organic reactions, as we already have seen for Grignard reagents (Section 14- 10).
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