DECARBOXYLATION OF HETEROFUNCTIONAL CARBOXYLIC ACIDS

Carboxylic acids with strong electron-withdrawing group at the α or β position can be decarboxylated. Amino and hydroxy acids as well as dicarboxylic and tricarboxylic acids are subjected to this reaction.

Acetoacetic acid is readily decarboxylated on slight heating to yield acetone.

α-Oxo acids eliminate carbon dioxide on heating in the presence of a dilute sulfuric acid whereas a concentrated acid promotes the removal of carbon monoxide.

α-Amino acids can be hardly decarboxylated in vitro on heating in the presence of strong alkalis to give primary amines.

Decarboxylation plays an essential role in metabolic processes. So, natural α-amino acids are transformed in such reactions into biogeneous amines. For example, the dicarboxylic compound glutamic acid gives rise to 4-aminobutyric acid (or γ-aminobutyric acid, abbreviated GABA), which is a natural neuroregulator.

Enzymic decarboxylation of pyruvic acid results in the formation of so-called «active acetaldehyde». It is then oxidized and acylates coenzyme A (abbreviated HS-CoA) at sulfur atom to give acetyl coenzyme A. The latter is a versatile carrier of the acetyl group in biochemical reactions.

HETEROFUNCTIONAL COMPOUNDS IN CHEMOTHERAPY

Perhaps, the noblest aim of chemistry consists in creation of drugs. The German physician and scientist T. Paracelsus, the founder of medicinal chemistry in the 16th century, said that the real objective of chemistry was not the production of gold but the preparation of drugs. A new science - chemotherapy - that appeared in the 20th century is defined as the use of chemical substances for medical purposes.

The author is aware that the discussion of this problem is beyond the scope of this book. This is a subject matter of other sciences, first of all, pharmacology and pharmaceutical chemistry. Nevertheless, some relatively simple examples of heterofunctional compounds used in medicine are given here.

Only trivial or trade names are given in this section because of the complexity of most systematic names. Besides, as it is well known, many medicines have numerous trade names. We give first a name applied in the Russian Pharmacopoeia and in Russian literature, then synonym(s) of the name in parentheses.