Please answer the following question correctly and completely. (Please write nea
ID: 534682 • Letter: P
Question
Please answer the following question correctly and completely. (Please write neatly for me to be able to see it clearly)
1. Take a look at this figure and do the followng:
A. There are four stereoisomers shown for intermediate "4" but only one for "5". The word "resolved" is written over the arrow between them. What does resolved mean? How might we be converting a mixture of four structures into only one structure?
Figure 3 CHO HON-Me co CHO COOH enantiomer OH Resolved COOH OH COOEt HOOC enantiomer three sterio isomers COOH COOH OH COOCH COOCH3 OH OCOC6H5Explanation / Answer
First of all those two structure drawn in 4 are diastereomers. Those two have enantiomers so total makes 4.Diastereomers have different physical properties so they can be seperated by any common methods such as recrystallisation, chromatography. After seperating two isomer like this, we have the drawn structure in 5 and its enantiomer only. These two stereoisomers are seperated by chiral resolution or optical resolution. Here resolved means chiral resolution. Chiral resolution is a method to seperate two enantiomers. This is a difficult process of seperation as enantiomers have same physical property. It took Louis Pasteur more than 30 years to discover this technique after he first discovered enantiomers. The most common techniques used are
1) Adding some specific reagent to crystallise the enantiomers differently.
2) Convert the enantiomers to diastereomers by reacting them with some reagent so that they are not mirror images to each other anymore and then they can be seperated easily.
3) Chiral column chromatography. Remember left hand and right hand are mirror image to each other and left gloves dont match with our right hand. So if we have some chiral molecule which can act like this gloves, we can seperate the enantiomers.