W4 Basic retrosynthetic approaches in drug synthesis (SF) 17.10

Question 1

What is meant by retrosynthetic analysis?
What is a TM?

Answer 1

Working backwards (inverse from R to L) as if synthesis was done from right to left
Target molecule

Question 2

What are the conditions before attempting a retrosynthesis?

Answer 2

• To minimise the costs and help make the synthesis as easy and green as possible,the % yield of TM should be maximised
  1. The number of single steps should be minimised, and they should be simple
  2. The yield of each step should be maximised to avoid side products

Question 3

Which is better?
Linear or Convergent Synthesis?

Answer 3

Convergent
* Lower amount of steps- better economy
* Shorter time
* Higher yields

Question 4

What are synthons?
What is the synthon approach?

Answer 4

Not real molecules, just a representation of how we would separate the charges

During the retrosynthetic analysis, the disconnection leads to a nucleophile (-) and an electrophile (+)
After disconnection, the -ve charge goes to the most electronegative atom or the most electron-rich

Question 5

What are some common synthons?

Answer 5

Donor Synthons: (Nucleophiles)
-CH2CHO CH3CHO and -CHO

Acceptor Synthons (Electrophiles)
-CO-

Question 6

What are some common disconnection points?

Answer 6

• C-C bond between C from phenyl ring and C from carbonyl group (C=O)
• C-C bond between C from phenyl ring and C aliphatic chain (C-C)
• C-C bond between two sp2 carbons: Suzuki coupling
• C-N bond amide- Nucleophilic Acyl Substitution

Question 7

What is Functional Group Interconversion?

Answer 7

• Using one functional group which leads to another
• So “Sacrificial group” will not be in the final molecule