Medicines By Design Flashcards
Combinational chemistry
Where several compounds are attached to solid beads - these are then all reacted with the same reagent in one flask. several new compunds are made but are easily separated as are attached to solid beads.
Organic synthesis steps
Start by looking at target molecule and its structure
By looking at functional groups chemists can work backwards to work out sequence of reactions until suitable starting material is found - RETROSYNTHESIS
Each step in synthesis will produce intermediate compound
Synthons and synthetic equivalents
Disconnect target molecule to obtain synthons.
Each synthon will have synthetic equivalent
How to chose what route in complex synthesis
Often one wi shortest steps.
Not always the case for those in industrial processes due to other factors - cost of reagents and starting materials, disposal of waste materials and possible health and safety hazards. Also overall yield and atom economy.
Some reactions produce a mixture of isomers, reduces yield and causes separation problems
Seperate get optical isomers is very difficult and time consuming, so usual method is to start with optically active starting material.
If enzymes are used to catalyse a reaction they will be stereospecific favoring production of one isomer
Molecular recognition
Bonding of neurotransmitter to receptor site at several points
Pharmacophore
Part of the molecule that produces the pharmacological activity
What is n.m.r?
Nuclei of some atoms have property called nuclear spin -behave as if they were tiny magnets.
If these nuclei are placed in a strong magnetic field, some align themselves in direction of field some against. Those aligned with will have Slightly lower energy than those aligned against.
If nuclei is given a pulse of radio frequency (RF) radiation, those in lower energy state are promoted to higher - called resonance. The excited nuclei return to their original state by lonsing the same amount of energy- this can be detected
If sample for n.m.r needs to be in solution then..
Deuterated solvents are used CDCl3 don’t contain any H so don’t disturb n.m.r
N.m.r how does it work
Sample is subjected to pulses of radio frequency radiation
Energy released when nuclei resonate is detected and converted to n.m.r spectrum on recorder.
Molecule used as reference giving chemical shift of 0
Tetramethylsilane TMS
Number of peaks
Number of different chemical environments
Position of chemical shift
Type of protons
Relative area under each absorption peak
Number of equivalent protons in each chemical environment
High resolution n.m.r
Amount of splitting indicates the number of hydrogen atoms attached to the carbon atoms next to the one youre looking at.
N+1 rule
