Workshop Tutorial ChemDraw

advertisement
Workshop Tutorial
ChemDraw
This tutorial is intended for use by students learning to draw
molecules and reactions.
Workshop Description:
This workshop is an introduction of drawing chemical
structures.
Workshop Title
Author
Date
1
Re: ChemDraw Tutorial
Your assignment is to synthesize the molecule 1,3,7Trimethylxanthine, also known as No-Doz, Refresh N’ Stim
and most popularly, CAFFEINE. You are armed with the
most powerful computer software EVER to be released…
…ChemDraw!
It’s in programs CS ChemOffice folder.
Chemical formula of caffeine: C8H10N4O2
To start with, there are a few things you should know. ChemDraw does not label carbon
atoms in the molecules. They are assumed to exist at the joint of two or more chemical
bonds. This is simple if you are trying to draw organic chemicals. ChemDraw also
assumes that hydrogen atoms are implied to exist around any atom that does not fulfill its
valence octet. For example, the structure of heptane can be drawn like so:
H
H
H
H
H
C
C
C
C
H
H
H
H
C
C
H
H
H
H
C
H
H
H
Choose the solid bond tool from the tool bar and draw this structure. When the bonds are
drawn, the bottom left corner of the screen shows the angle of the bond line you are
drawing. The C-C bonds should be at 30° angles from horizontal. Notice that the ends of
the bonds are highlighted when the cursor crosses over them. Type an element’s letter at
this time to put an atom there. This is how you label the H’s and C’s. Other letters can be
typed in manually by double clicking on the atom.
That takes a long time. This way is easier and there’s a special tool for it called the
Acyclic Chain tool on the toolbar (it’s got the little “n” on it). ChemDraw recognizes this
symbol as the same molecule we just drew.
If you were to add on an alcohol group, you could do so with almost as much simplicity.
All atoms besides carbon and hydrogen should be labeled. The double bond here says
that the O atom satisfies its valence octet:
Workshop Title
Author
Date
2
O
A Cyclohexane ring is a hexagonal structure of carbon and hydrogen atoms that can be
described by this symbol:
There is one of these in the caffeine molecule. Use the Cyclohexane tool to draw one in
the center of your ChemDraw page. Next we will use the Cyclopentane tool to attach a
cyclopentane ring to the hex ring like so:
Be careful to start the pentane ring from an atom of the hex ring so that ChemDraw will
recognize it as a connected structure.
This is the final structure of caffeine:
O
N
N
O
N
N
Additionally, we need you to retrieve some information about this molecule. We need the
chemical’s ACX number and an elemental analysis included in your report. ChemDraw is
a great tool that can be used in many other ways. Go to the Help menu Contents Chapter 2, Tutorials for more step-by-step instructions.
Good luck, 007,
Q
Workshop Title
Author
Date
3
Download