Anesthetics or analgesics necessary for surgery are a kind of drugs that have been studied thoroughly. Chemists have fully demonstrated their talents in this respect. Their research results on the natural drug coca base have finally replaced them with a more ideal synthetic product, which has stronger effects and no side effects and risks.
The earliest local anesthetic was cocaine or cocaine extracted from coca plants growing in South America, but it was easy to become addicted and toxic. After understanding the structure and pharmacological effects of cocaine, people have synthesized and tested hundreds of local anesthetics, Benzocaine And procaine are two of them. Active drugs of this kind that have been found have the following common structural characteristics: one end of the molecule is an aromatic ring, the other end is a secondary or tertiary amine, and the two structural units are separated by an intermediate chain of 1-4 atoms. The benzene ring part is usually aromatic ester, which is closely related to the detoxification of anesthetics in the human body; The amino group also helps to make such compounds form water soluble hydrochloric acid for injection. 
