To which class of chemicals does caffeine belong?

Caffeine belongs to the class of chemicals known as xanthines. Xanthines are a group of compounds that include several stimulants, with caffeine being the most widely consumed. This class is derived from purines, which are fundamental building blocks of nucleic acids and play significant roles in cellular metabolism.

Xanthines are characterized by their structure, which includes a purine base that is further methylated; caffeine specifically has three methyl groups attached. This structural alteration ultimately provides the stimulating effects associated with caffeine, affecting adenosine receptors in the brain and leading to increased alertness and reduced fatigue.

In contrast, phenylethylamines are another class of compounds that include substances like amphetamine, which are distinct from xanthines in both structure and function. Purines, while related to xanthines, are a broader category that encompasses a variety of biologically active compounds. Lastly, carbamates refer to a group of chemicals often associated with pesticides and insecticides, making them unrelated to caffeine's stimulant effects. Thus, caffeine is correctly classified as a xanthine because of its specific chemical structure and biological effects.