Transcript Option D: Medicines and Drugs Unit D.3.3: Structural Comparisons

Option D: Medicines and Drugs
Unit D.3.3: Structural Comparisons
of Analgesics
Chemistry SL
Dixon Adair
Introduction to Opiates
• “The most important naturally occuring
strong analgesics are morphine and
codeine found in the opium poppy.
• “Morphine, codeine and semi-synthetic
opiates…, such as heroin, all possess the
same basic structure.”
• Source: Textbook
Structural Diagrams
• “In
codeine one of
the hydroxyl
groups has been
substituted for an
ether group…”
(Textbook)
• The opiates
shown here are
naturally occuring.
Codeine
• “Codeine (INN) or methylmorphine is an opiate
used for its analgesic, antitussive and antidiarrheal
properties. It is by far the most widely used opiate in
the world…It is one of the most effective orallyadministered opioid analgesics and has a wide
safety margin. It [has] from 8 to 12 percent of the
strength of morphine in most people…”
(Edinformatics)
• “Codeine is an alkaloid found in opium poppy, a
plant in the papaveraceae family that has been
cultivated and utilized throughout human history.
Codeine can also be acquired in saps from other
poppies such as Papaver bracteatum, in
concentrations ranging from 0.3 to 3.0 percent.
• While codeine can be extracted from opium, most
codeine is synthesized from morphine through the
process of O-methylation. [SEE PREVIOUS SLIDE]
It was first isolated in 1832 in France by Jean-Pierre
Robiquet.” (Wiki)
Morphine
• “Morphine (INN) (pronounced /ˈmɔrfiːn/)
(MS Contin, MSIR, Avinza, Kadian,
Oramorph, Roxanol) is an extremely
potent opiate analgesic psychoactive drug,
is the principal active ingredient in Papaver
somniferum (opium poppy, or simply
opium)…”
• “In clinical medicine, morphine is regarded
as the gold standard, or benchmark, of
analgesics used to relieve severe or
agonizing pain and suffering.”
• “Morphine acts directly on the central
nervous system (CNS) to relieve pain.
Morphine has a high potential for addiction;
tolerance and both physical and
psychological dependence develop rapidly.”
• Source for above: Wikipedia
Heroin: Introduction
• “Diamorphine (heroin) is
more powerful and addictive
than morphine.” (Textbook)
• Heroin is a semi-synthetic
opiate.
• Definition of Semi-Synthetic:
“Semisynthesis" or partial
chemical synthesis is a type
of chemical synthesis that
uses compounds isolated
from natural sources (e.g.
plant material or bacterial or
cell cultures) as starting
materials. These natural
biomolecules are usually large
and complex molecules.”
(Wikipedia)
Two ester groups, hence the name
“Diamorphine” (more properly
known as diacetylmorphine)
(commonly known as heroin)
Heroin: The Name
• “Heroin, or diacetylmorphine
(INN), also known as diamorphine
(BAN), is a semi-synthetic opioid
drug synthesized from morphine, a
derivative of the opium poppy. It is
the 3,6-diacetyl ester of morphine (di
(two)-acetyl-morphine).” (Wiki)
• Diacetyl means two acetyl groups,
but what is an “acetyl” group or an
acetate?
• “An acetate (IUPAC name:
ethanoate) is either a salt or an ester
of acetic acid.” (Wiki)
• Acetic Acid (or ethanoic acid) is
seen in the diagram to the right.
• Ethanoic anhydride is simply
“dehydrated” 2 CH3COOH which
turns into ethanoic anhydride, after
losing its OH.
Q: Why is this
important?
A: The diacetyl part
of heroin is what
distinguishes it from
its original source:
morphine.
Heroin: How it’s Made
•
•
•
“…heroin is the diester
[i.e. two esters] formed
from the condensation of
morphine with ethanoic
anhydride.”
The process described
above is done by reflux.
Reflux is a technique
involving the
condensation of vapors
and the return of this
condensate to the
system from which it
originated. It is used in
industrial and laboratory
distillations.
Diesterification with
ethanoic anhydride, above
+ 2 Ethanoic Acid
Ethical Issues
• As we can see, codeine, morphine, and heroin
all possess the same basic structure, yet their
“slight” chemical differences make them have
very different effects on humans.
• Where do we draw the line between what
derivatives of morphine can/should be used?
• Is there such thing as an analgesic which is
TOO strong, such as heroin?
Additional Information
• Poppy seed is an oilseed obtained from the opium poppy (Papaver
somniferum). The tiny kidney-shaped seeds have been harvested from
dried seed pods by various civilizations for thousands of years. The seeds
are used, whole or ground, as an ingredient in many foods, and they are
pressed to yield poppyseed oil. (Wiki)
• To some extent harvesting for poppy seeds is in conflict with harvesting
for opium. Poppy seeds of superior quality are harvested when they are
ripe, after the seed pod has dried. Traditionally, opium is harvested while
the seed pods are green and their latex is abundant, but the seeds have
just begun to grow. (Wiki)
Thank You