Option D7 Flashcards
How do chiral drugs exist?
They exist in 2 forms with different activities
How do enantiomers react in a chemical environment
Regardless of their similar chemical properties, they act in different ways
What does in vivo synthesis yield?
Biological synthesis reactions within cells (in vivo) produce only one enantiomeric
form.
What does in vitro fertilization yield
A mixture of enantiomers,
known as a racemate
What challenges do pharmaceutical companies face in this context?
Determining the effects of each enantiomer, in order to check whether to market the drug as racemate or single enantiomer
What was the reason for scientists to make these differentiation
Thalidomide incidence
Why was the thalidomide mixture a starting point for the scientists’ research?
It was sold in a racemic mixture form, however only the (R) isomer showed the effect of inducing sleep in women, while the (S) isomer was teratogenic
What are examples of racemic mixtures that are marketed as drugs
Ibuprofen and Prozac
What is chemotherapy
The treatment or control
of disease by chemical
agents. It is generally
used in the context of
cancer treatment.
What is Taxol
It is a powerful anti-cancer drug
What is Taxol known as and to what group does it belong?
Taxol is also known as Paclitaxel, and is part of taxoid group
How is Taxol used?
It is used
primarily in the treatment
of breast and ovarian
cancers.
How do the anti cancer properties of Taxol arise?
Due to its ability to bind to a protein known as tubulin
What is tubulin?
It is the main component of microtubules that makes up spindles during cell division
How does Taxol stop growth of tumor?
As Taxol binds to the tubulin, the microtubules will breakdown and halt the cell division therefore preventing the spread of tumor
How was Taxol first discovered?
Taxol was first isolated from the bark of Pacific yew trees (Taxus sp.) in the
1970s.
Why did the practice of removing the Taxol from bark trees become controversial?
The process of stripping the bark kills the trees, which take 200 years to
mature and are part of a sensitive ecosystem
What is asymmetric synthesis?
The production of a single enantiomer
of Taxol
What challenges came with the synthesis of Taxol?
It is made of of 11 chiral centers with only one of them having therapeutic effects
What is a strategy to synthesize Taxol?
The use of a chiral auxilary
What is a chiral auxiliary?
This is a chiral molecule which binds to the reactant, physically blocking one reaction site through steric hindrance, so ensuring that the next step in the reaction can only take place from one side. This effectively forces the reaction to proceed with a specified stereochemistry.
What happens to chiral auxiliary when the desired product is received
It is taken off and recycled
What difficulties arose because of the complex structure of Taxol
Its synthesis from simple compounds took 30 steps, with a very poor yield
What is considered to be a more efficient way to synthesize Taxol?
The extraction of a compound from the needles and leaves of yew trees which is similar to Taxol.
