The analogy I want to use is pottery.
When you make something out of clay, first you put it together, and then you fire it in the kiln. Chemistry is like this: first you arrange the
reagents, then they react. What you've asked is, basically, why can't I modify something (the structure of glycerol) while I'm reacting it with
something else (phenylalanine). And the answer is that it's in the kiln! You can't perform two reactions at once because the reagents for the
different reactions will start to react with each other. It's like trying to modify a piece of clay while you're firing it: it doesn't work that way.
Every time you want to change it, you have to take it out of the kiln and cool it off (extraction and isolation).
This is the biggest problem with your post, because it's a fundamental fact about all chemical reactions that people have to absorb before they can
start trying to synthesize anything. It takes a while to really internalize this rule, and usually the only thing that does it is practical lab
experience.
Once you start to look at chemistry in a properly step-wise manner, it becomes obvious why what you're proposing doesn't make any sense. If
you have to break apart the C-C bonds in glycerol and then extract and isolate the product before you do anything else with it, you might as
well start with methanol!
The other big glaring issue is that you think Friedel-Crafts reactions can attach oxygen to benzene, but in reality they only attach carbon atoms to
benzene. Mescaline has oxygen atoms attached to benzene. If you have a formyl benzene with a structure like (Ar-C-O), it will never rearrange
to a structure like (Ar-O-C) unless you use a rearrangement reaction (in this case, the Dakin reaction, but the result is a phenol).
Adding to the trouble, Friedel-Crafts reactions with AlCl3 cannot be performed on phenylalanine at all. In this case, I leave it to you to
learn why.
You just can't ask a question this advanced starting from a position of such total ignorance. You need to learn the fundamental rules of organic
chemistry in order to be able to make sense of anything.
"Philosophers often behave like little children who scribble some marks on a piece of paper at random and then ask the grown-up "What's that?" -
It happened like this: the grown-up had drawn pictures for the child several times and said: this is a man, this is a house, etc. And then the child
makes some marks too and asks: what's this then?"
It's nothing, see?
[Edited on 2-10-2018 by clearly_not_atara] |
