[CelticKhemist2000]

Not sure how to ask this question, I hope I can get a great, and edifying answer. I've been studying monomers and polymers recently, reading about the different methods used for synthesizing plastics. How high temperatures and catalysts are used to bind monomers to make carbon chains. Something still confused me though.

I saw a police story about a cop that used Ketamine on a suspect so I looked up the molecule and saw several similar molecules (methoxetamine, phencyclidine, tenocyclidine, tiletamine, eticyclidine, rolicyclidine, etc).

So when it comes to organic chemistry, what are the consistent methods for how they form these chemical structures almost like legos? I know they don't have atomic sized robot hands connecting them into certain shapes. How can they dictate the shape of the organic molecules using the same elements? What process determines the shape of an organic molecule?

[Borek]

There is no universal approach, but there are hundreds (if not thousands) of reactions that can be used to add an atom here or there, or to modify a functional group in a particular way, or break a bond, or move it and so on. You find an already existing and cheap molecule and look for a way a way of modifying it so that you get what you need. That's usually tricky as all these reactions have their intricacies and limitations.

[rolnor]

It seems as if you want us to explain the area of organic chemistry, this usually takes several years full-time studies.

[kriggy]

The methods of organic chemistry are fairly consistent mostly. There is a set of reactions that pretty much work all the time no matter what are the specific structures of the substrate you are using. Those are reactions like amidation, Suzuki coupling, Buchwald-Hartwing coupling if you are interested... thats why quite a few of current drugs are "fairly similar" in structure (in broad sense) They are primarly made by those reliable reactions.

Making a chemicals is bit like making a furniture. You pick your material, wood,  screws, glue etc... and you make a table. But your friend is making a table as well but he uses wooden pins instead of screws and paints the table red in the end. There are various methods, some better some worse how to make a table but in the end, you end up with a table. Its same in chemistry, there are multiple methods how to make the this one compound but some are better, some are worse.

[rolnor]

The methods of organic chemistry are fairly consistent mostly. There is a set of reactions that pretty much work all the time no matter what are the specific structures of the substrate you are using. Those are reactions like amidation, Suzuki coupling, Buchwald-Hartwing coupling if you are interested... thats why quite a few of current drugs are "fairly similar" in structure (in broad sense) They are primarly made by those reliable reactions.

Making a chemicals is bit like making a furniture. You pick your material, wood,  screws, glue etc... and you make a table. But your friend is making a table as well but he uses wooden pins instead of screws and paints the table red in the end. There are various methods, some better some worse how to make a table but in the end, you end up with a table. Its same in chemistry, there are multiple methods how to make the this one compound but some are better, some are worse.

This seems strange to me, the drugs are often close to phenethylamine, thats why they are similar? And I dont think they are made via Suzuki coupling?

[kriggy]

YOu are correct, I ment drugs like medications in general, not illicit drugs. I used bad wording.

https://pubs.acs.org/doi/10.1021/acs.jmedchem.5b01409