Tetraphenylcyclopentadienone

The purpose of this lab was to prepare tetraphenylcyclopentadienone most commonly known as tetracyclone. This involved a 3-step synthesis over the course of 3 weeks. The first step was the preparation of benzoin, which was completed through self-condensation of benzaldehyde with thiamine used as the base catalyst of the reaction. The next step was the preparation of benzil from the oxidation reaction of benzoin with nitric acid. In the oxidation reaction, the alcohol functional group of benzoin was oxidized to form the carbonyl functional group of benzil, while the nitric acid was reduced into a mixture of nitrogen oxides that formed toxic brown fumes. The final step was the preparation of tetracyclone from the aldol condensation reaction of…

The dibenzylketone, 1,3-diphenyl-2-propanone, undergoes two consecutive base-catalyzed aldol condensations with the benzil to form the dark purple product tetraphenylcyclopentadienone. As shown in the mechanism below, the first step is the loss of an alpha hydrogen on the dibenzyl ketone to form the enolate anion. This step must occur on the dibenzyl ketone and not the benzil because the benzil does not have an alpha hydrogen to give away and therefore is incapable of making the enolate.…

by the orientation of the final product (Kilway). Experimental Section Dimethyl Tetraphenylphtalate. Tetraphenylcyclopentadienone (0.102 g, 0.265 mmol) was dissolved in a soln of dimethyl acetylenedicarboxylate (0.1 mL, 0.09 g, 0.7 mmol) and nitrobenzene (1 mL). The purple/brown soln was then placed into a small reaction tube with a boiling stick and heated to reflux using a sand bath. Ethanol (3 mL) was added to the mixture. After reflux caused a color change to a light red/brown, the soln…