Separating stereoisomers Difficult to make just one so...Difficult to make just one so... Make a racemic mixture 50/50Make a racemic mixture 50/50 Then separate the enantiomersThen separate the enantiomers Chiral chromatographyChiral chromatography Stereoselective (asymmetric) synthesisStereoselective (asymmetric) synthesis Using chiral auxillariesUsing chiral auxillaries Pure enantiomer combines with non-chiral reactant to form chiral intermediatePure enantiomer combines with non-chiral reactant to form chiral intermediate

taxol Originally obtained from Pacific yew tree barkOriginally obtained from Pacific yew tree bark Semi-synthetic process from the needlesSemi-synthetic process from the needles Now fermentation using plant cell culturesNow fermentation using plant cell cultures Anticancer drugAnticancer drug Prevents cell divisionPrevents cell division

An enantiomer rotates plane-polarized light clockwise (+) Rotates it counterclockwise (-)

Specific rotation = [] The angle which the light is rotated in degrees = () The path length of solution the light passes through ( l ) dm Concentration of solution (c) in gcm -3 depends on wavelength of light used, temp, and solvent Relies on purity of sample

Extraction of drug After synthesis of a drug it must be extracted form the reaction mixture Depends on solubility Presence of Non-polar, polar, H-bonds Insoluble solids can be added to ice water Precipitate can be removed by filtration Solvent extraction Shaking aqueous mixture with an immiscible solvent Separation funnel

purification Recrystallization Distillation Different boiling points Fractional distillation similar boiling points Uses vapor pressure chromatography

Raoult’s law Vapor pressure Pressure exerted by a vapor in equilibrium with its liquid or solid The contribution of each component of a mixture to the total vapor pressure depends on what the vapor pressure of the pure liquid is and how much is present in the mixture. P A = X A x P A

Nuclear medicine Alpha, beta, gamma, proton, neutron, positron emission Radioactivity is used in the diagnosis and treatment of disease. Radioactive atoms are incorporated into drugs or biochemical mcs and are injected into the body Molecules cruise through the body and are watched by a radiation detector

radiotherapy Treatment of disease (cancer) using radiation Ionizing radiation can interact directly with the DNA of highly replicating cells or form free radicals Water HO (hydroxyl radical) Super dangerous DNA, protein and lipid destroying free radical External or internal source of radiation

Side effects of radiotherpy Damages healthy cells in the area of treatment Temporary Hair loss Nausea Fatigue Permanent sterility

Technetium-99m Most common radioisotope used in medicine m-refers to metastable state Long-lived excited nuclear state Decays to Tc-99 emitting gamma rays Half-life = 6 hours Long enough for full body travel Short enough for minimal damage from radiation Can be made water soluble TcO 4 -

β emitters Internal radiotherapy Interact with matter more effectively Lose energy with a few millimeters in the body Yttrium-90 Half-life = 64 hours Treats liver cancer Tiny beads are injected into the liver artery—killing tumor cells

Lutetium-177 Half-life = 6.71 days β-emitter and γ-emitter Used for treatment of neuroendocrine cancer Or imaging

Targeted alpha therapy - particles Large Highly charged cause great damage to a small area Cannot penetrate skin 20 - particles kill one cell Monoclonal antibodies (same shape) Target cancer cells Astatine-211 Half-life=7.2 hours Pb-212 Half-life =10.6 hours

Radioactive radium chloride Ra-223  and γ emitter Half-life = 11.4 days Treat bone cancer The body takes up Ra like Ca killing the cancer cells

Boron-neutron capture therapy Head and neck cancer Non-radioactive B-10 is taken in by cancer cells Its irradiated with a neutron beam Makes B-11 Makes an  particle Kills the cancer

Magnetic resonance imaging MRI Uses nuclear magnetic resonance to produce 3-d images of internal organs Why is the name nuclear missing from MRI? TOK blah

Drug detection and analysis infrared spectroscopy

H NMR

ethanol

Steroid detection Non-polar Steroid backbone Anabolic steroids Promote tissue growth Breast growth in men Acne Infertility Mood swings Aggressiveness High blood pressure, heart attack, stroke Liver disease

Steroids are broken down to metabolites in the body Detected by gas chromatography and mass spectrometry from urine Separation depends on how quickly components travels (solubility in the liquid stationary phase). More soluble slower component

Detection of alcohol Breathalyzers Redox acidified dichromate Orange to green (dichromate to chromium III ion) Alcohol to aldehyde to acid

Fuel cell Two Pt electrodes Oxidizes the alcohol Converts energy into electrical energy Oxygen is reduced