This news item was created by students Tiffany Whitaker and Cristi Van Veen as part of their Chemistry 210 Semester Project in WS99 under the guidance of Prof. Rainer Glaser.

Glaser's "Chemistry is in the News"
To Accompany Wade Organic Chemistry 4/e.
Chapter 2. Structure and Properties of Organic Molecules.

For each of the following questions, please refer to the following article:

Columbia Missouri Tribune Online, October 12, 1998.

Editorial Comments

In 1998, a Nobel Prize was given to three men: Robert Furchgott, Louis Ignarro, and Freid Murad for their work in finding that nitric oxide helps to regulate blood vessels. Discovering nitric oxide's involvement helped to develop the anti-impotence drug, Viagra.

Impotence had been found to affect ten percent of the male population. This discovery by these three men has helped many men with this problem. There are many causes for impotence, many that can be helped with Viagra.

Nitric oxide tells the blood vessels to relax and widen to allow more blood flow through the penis. The popular Viagra help to increase the nitric oxide's effect.

Viagra has an active ingredient sildenafil citrate but does not use it in a direct way. It uses it to enhance the effect of the nitric oxide. Nitric oxide in turn inhibits phosphodiesterase type 5 (PDE5). PED5 causes the degradation of guanosine monophosphate (cGMP). The absence of cGMP causes the problem of impotence.

In short, nitric oxide increases levels of cGMP in the penis causing the inflow of blood. Nitric oxides do this by using specialized enzymes. The structure of cGMP and nitric oxide can be found on Chemfinder.

Pertinent Text References Chapter 2: Structure and Properties of Organic Molecules


Question 1: There are many molecules involved with nitric oxide and Viagra that are very important. Find the structures of nitric oxide, cGMP, and sildenafil citrate.

A. Use the ChemFinder.

Question 2: The Nobel Prize was given to the importance of nitric oxide in the regulation of blood vessels. How is nitric oxide involved with Viagra in reversing impotence?

A. Sildenafil citrate in Viagra enhances the effects of nitric oxide. Nitric oxide inhibits phosphodiesterase type 5. PDE5 causes the degradation of cGMP, so if PDE5 doesn't eliminate the cGMP there will be no problem of impotence.

Question 3: What are the hybridizations of the carbon atoms at these points on the sildenafil citrate?

A. 1-sp2, 2-sp3, and 3-sp3.

Question 4: Do you think that these men are worthy of a Nobel Prize for this discovery?

A. Insert your own opinion here.