It's not easy to put that Nitrogens in the middle of the chain. Moreover, the method to produce it is to mix some smaller chains that have the Nitrogen in the ends of the chain and make them combine in a longer chain.
This produces a mix of a lot of similar chains with different length and number of Nitrogen. They have similar properties, so it is difficult to separate them. They use distillation. But at high temperature that Nitrogens like to burn, so heat the mix carefully.
Also, the mix you produce have a lot of compounds with the same "2D" formula, but they have a different shape in "3D". Some of the versions may have totally different properties, like been very toxic. So you must separate them too, and again, it's difficult.
Note: I studied a Chemistry specialization in the Secondary School, so I have some general knowledge about this, but I'm far from an expert in medical drug production.
Note 2: If you like this kind of things, I recommend to see the Nile Red channel in YouTube https://www.youtube.com/channel/UCFhXFikryT4aFcLkLw2LBLA It's nice to see some easy and not so easy projects, and he explain the reactions, and the problems and pitfalls he found. (I don't understand everything he does.)
---
Anyway, the difference of the cost of the medical drug and the chemistry drug is annoying.
It's not easy to put that Nitrogens in the middle of the chain. Moreover, the method to produce it is to mix some smaller chains that have the Nitrogen in the ends of the chain and make them combine in a longer chain.
This produces a mix of a lot of similar chains with different length and number of Nitrogen. They have similar properties, so it is difficult to separate them. They use distillation. But at high temperature that Nitrogens like to burn, so heat the mix carefully.
Also, the mix you produce have a lot of compounds with the same "2D" formula, but they have a different shape in "3D". Some of the versions may have totally different properties, like been very toxic. So you must separate them too, and again, it's difficult.
Note: I studied a Chemistry specialization in the Secondary School, so I have some general knowledge about this, but I'm far from an expert in medical drug production.
Note 2: If you like this kind of things, I recommend to see the Nile Red channel in YouTube https://www.youtube.com/channel/UCFhXFikryT4aFcLkLw2LBLA It's nice to see some easy and not so easy projects, and he explain the reactions, and the problems and pitfalls he found. (I don't understand everything he does.)
---
Anyway, the difference of the cost of the medical drug and the chemistry drug is annoying.