In this PC Lab exercise in the ChemTech PC Lab (Foster Hall 326), you will be using the software ChemDraw, purchased from Cambridge Software by a National Science Foundation grant to the Chem Dept. This software allows one to easily generate structural formulas of complicated organic molecules for printout or inclusion in other documents. Today we will use this program to draw the structural formula of aspirin.

1. Launch ChemDraw by clicking on START/Programs/Chemistry/Cambridge Software/ChemDraw Pro.
2. Familiarize yourself with the graphical user interface of the program. First use the expand button in the upper right hand corner of a window to make use of the entire screen.
3. Note the Tool bar that appears on the right side of the screen. By positioning the cursor over any one of these buttons the program tells you the function of that tool button.
4. Select the benzene ring tool button (appears at the bottom of the tool bar).
5. Click somewhere near the center of the white drawing space and a benzene ring will appear on the screen. This is the basic structural element of the compound.
6. At any time, a command may be "undone" by choosing Undo in the Edit menu.
7. Additional groups may be added to the benzene ring by selecting the Bond tool near the top of the tool bar. With this selected, drag from one of the carbon atoms on the ring to a point outside the ring to append a carbon atom to the ring. Continue doing this until you have the basic skeleton of the molecule of interest, not worrying yet that some of these new atoms should not be carbons but should be Oxygens. That will be fixed later.
8. To make a double bond use the Bond tool and drag over the top of an existing single bond to make it into a double bond. This will be needed to create C=O bonds.
9. Now you are ready to convert some of these atoms from carbon (the default) to oxygen. To do this, simply position the cursor over the top of the desired atom until the black square box appears, but DO NOT click the atom. Simply type an "O" to change the selected atom to an Oxygen.
10. After you have finished getting the structure you want, use the Text tool to annotate the drawing by putting the name of the compound above it, and putting your name in the upper right hand corner.
11. Save the structure on your U: drive and generate a printout of the structure to hand in.

OPTIONAL: Convert this 2-D structural formula to 3-D by copying it and pasting it into the program CHEM3D. After the paste you need to select MM/Minimize Structure to refine the structure’s geometry into something energetically plausible.