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CHEM 112 Study Guide - Final Guide: Positron Emission Tomography, Chiral Auxiliary, Principal Quantum Number


Department
Chemistry
Course Code
CHEM 112
Professor
Nicholas Mosey
Study Guide
Final

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Penicillin
A bacteriologist mistakenly left a petri dish open and noticed a blue-green mold developed
which prevented the growth of his bacteria. This antibacterial fungus later became known as
penicillin
This antibiotic drug saved more lives across the world than any other pharmaceutical drug
The term “penicillins” is used as a collective name for a group of structurally similar natural and
synthetic substances
Mechanism of penicillin
A distinctive feature of penicillins is the four membered beta-lactam ring, responsible for
antibacterial properties of these drugs
This beta-lactam ring is highly reactive and irreversibly binds to the enzyme transpeptidase in
bacteria. This weakens their cell wall causing water to flow into the bacteria until the water
pressure bursts the bacteria open
Human and other animal cells don’t have cell walls therefore are not affected by penicillin
Certain bacteria mutated and developed varying degrees of antibiotic resistance due to
increased production of enzyme called penicillinase. This enzyme could deactivate penicillin
and preventing it from binding to transpeptidase. Over time, this species of bacteria became
the dominant species, reducing effectiveness of bacteria
To overcome this resistance, new penicillins with modified side chains were developed
This continued production of penicillin triggered multidrug resistance (MDR) in bacteria. MDR
bacterial infections require a combination of many different antibiotics and strict patient
compliance to solve the issue
D.3 Opiates
Opium and opiates
The primary ingredient of opium, morphine, is a natural analgesic which belongs to the group
of alkaloids
Alkaloids: naturally occurring chemical compounds containing nitrogen atoms
Although morphine can be synthesized in the laboratory, its usually extracted from the opium
poppy
Morphine and its derivatives (classified as opiates) are strong analgesics, which temporarily
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Morphine and its derivatives (classified as opiates) are strong analgesics, which temporarily
bind to opioid receptor sites in the brain, preventing the transmission of pain impulses without
depressing the central nervous system (in contrast to mild analgesics which block transmission
at site of pain)
Side-effects include constipation, suppression of cough reflex, constriction of
the eye pupil, narcotic effects.
o
Opiates are also known as narcotic analgesics because in addition to painkilling, they also cause
a strong feeling of euphoria and provide relief from all forms of distress
As a result, these drugs lead to drug addiction and dependence
Crossing the blood-brain barrier
The physiological effects of opiates depend on their ability to cross the blood-brain barrier
Blood-brain barrier: a series of lipophilic cell membranes that coat the blood vessels in the brain and
prevent polar molecules from entering the central nervous system (CNS)
The presence of hydroxyl and amino groups in morphine make it polar and soluble in water but reduces
solubility in lipids. This limits the ability to reach opioid receptors in brain
The polarity of morphine can be reduced by chemical modification of one the hydroxyl groups
creating codeine
Codeine passes the blood-brain barrier then slowly metabolizes into morphine and binds to opioid
receptors
As a result, codeine is a 10x less potent analgesic than morphine and is thus used widely across the
world. It has a wide therapeutic window as well.
Diamorphine (Heroin)
When both of the hydroxyl groups are substituted with ester groups, it reduces the polarity of the
molecule producing diamorphine
Diamorphine can be prepared from morphine the same way as aspirin is prepared from salicylic acid and
ethanoic anhydride
Diamorphine passes the blood brain barrier easily and quickly metabolizes into morphine b/c it is more
soluble in lipids b/c of ester groups
Diamorphine is a 5x more potent analgesic than morphine and has more severe side effects
Is responsible for 50% of all drug related deaths around the globe. This drug is banned in most countries
around world
D.6 Environmental impact of some medications
Medicinal waste and the environment
For many years environmental impact of medicine has been ignored
Pharmacologically active compounds (PACs) used in medicine and biochemical studies have not been
treated as toxic and have been released into environment. However, prolonged exposure to PAC causes
significant change in metabolism of organisms
Another pollutant is radioactive materials which is harmful to environment despite its low activity
Increasing exposure to radiation can cause apoptosis (programmed cell death) in lymphocytes (white
blood cells), untimely reducing immune response and increasing risk of contracting diseases
Nuclear waste increases probability of developing cancer, birth defects, reproductive disorders and
weak immune system
Antibiotic resistance
Widespread use of penicillin and other antibiotics have led to development of antibiotic resistance in
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Widespread use of penicillin and other antibiotics have led to development of antibiotic resistance in
bacteria
As a result, bacteria are resistant, so scientist make new drugs to combat this, but over time, bacteria
become resistant to those as well
Over-prescription of antibacterial
Non-compliance of patients
This method causes fastest antibacterial resistance because it gets into environment and
humans, giving time for bacteria to resist its effects
Use of antibacterial in agriculture (Given to animals prevent disease, promote livestock growth)
Release of antibacterial waste by hospitals
Factors causing antibiotic resistance
Since 1990’s use of antibiotics have been mostly banned and are now only used for the most severe
bacterial infections to prevent bacterial resistance
Nuclear Waste
Many medicinal procedures involve use of radionuclides which are unstable isotopes of certain
elements that undergo spontaneous radioactive decay
When radionuclides come into contact with various materials, those irradiated materials and the
radionuclides are described as nuclear waste
Caused by radionuclides used in hospitals due to low activity and short half-life decay
The major radionuclides used for radiotherapy are also included in LLW
Low level waste: waste that gives off small amounts of ionizing radiation for a short time
Caused by nuclear reactors and contains products of nuclear fission. Have long half-life decay and
require proper treatment and storage underground to prevent radiation damage
High level waste: waste that gives off large amounts of ionizing radiation for a long time
Effects of antibacterial and radioactive waste can be cumulative. It is best to dispose of each type of
waste in their respective ways to prevent potential hazard from combined effects
Waste from pharmaceutical industry
Most of the waste is organic compounds
Chlorinated solvents ( CHCl3, CCl4, CH2Cl2) present the hazard of causing ozone depletion and contribute
to formation of “photochemical smog”
The disposal of chlorinated solvents is an expensive and complex process. Hard for industry to pay for
that
Green Chemistry
Efficiency of a reaction in regular chemistry is measured in terms of product yield and cost of raw
materials
Green chemistry focuses on reducing environmental impact by minimizing use of hazardous materials
Another important focus is the use of biotechnologies in organic synthesis
For many years shikmic acid was extracted from a natural source however, outbreak of bird flu in
2005 resulted in increased demand of oseltamivir, and thus shikimic. Green scientists then
produce shikimic acid from E. coli effectively presenting shortages of oseltamivir in future
Shikimic acid is a precursor to the antiviral drug oseltamivir (Tamiflu)
Extinction of plant species
Rising food prices
Industrial use of natural products leads to issues:
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