The Diels-Alder reactions consist of a reversible dienophile and diene all in a one-step reaction initiated by head. These reactions form a six membered ring with at least one pi bond and two sigma bonds, making the reaction exothermic. The goal of the first part of these experiments is to make products that have a greater aromatic stabilization. In 1928, Otto Paul Hermann Diels and Kurt Alder first documented this type of reaction, hence the name Diels-Alder reactions. Their reaction is one of the more useful reactions done in chemistry because it does not require very much energy in order to make the cyclohexene ring and the result can create four stereo centers, making it compatible for a variety of functional groups which still has double bonds in the products.
Tetraphenylcyclopentadienone (0.100g), dimethyl acetylene-dicarboxylate (0.1mL), and nitrobenzene (1mL) was placed into a reaction tube with a boiling stick. The reaction was heated until the purple solution turns tan and refluxed.
Ethanol(3mL) was stirred in after the solution was warm, and placed in ice.
The solid was vacuum filtered, washed with ethanol, dried and weighed. Hexaphenylbenzene. Tetraphenylcyclopentadienone (0.100g) and diphenylacetylene (500mg) was placed in a reaction tube and loosely capped. The solid was heated to reflux with a sad bath until the solid turned a brown color.
The tube was shaken gently to bring about white solids at the bottom of the reaction tube. Diphenyl ether(2mL) was added and heated until the solid dissolved. The reaction tube was cooled again and had toluene(2mL) added then placed in ice. The product was vacuum filtered, washed with toluene, dried, and weighed. Tetraphenylnaphthalene. Tetraphenylcyclopentadienone(0.500g), glyme(3mL), and a boiling chip was added to a reaction tube. Isoamyl nitrite(0.35mL) was added via syringe to reaction tube and heated to reflux for 2-5 minutes. Anthranilic acid(0.250g) and glyme(2mL) was dissolved in a separate reaction tube, then added to refluxing solution dropwise via pipette. The color changed from brown to yellow after 5 minutes, and then heat was added for another 2 min. The mixture was shaken and cooled to room temperature.
Ethanol(10mL) and saturated sodium bicarbonate(5mL) was added to the solution and shaken to allow solid to form. The solid was vacuum filtered, washed two times with cold water, then two times with cold ethanol. The product is then recrystallized with nitrobenzene/ethanol, filtered, dried and weighed. The melting point was recorded. Triptycene. Anthracene(0.400g), isoamyl(0.4mL), glyme(4mL) and a boiling chip was placed into a reaction tube and heated using a sand bath. Anthranilic acid(0.520g) was dissolved into glyme(2mL).
Anthranilic acid solution was added deopwise via pipette into refluxing apparatus over a twenty minute period, followed by isoamyl nitrite(0.4mL). the mixture was refluxed for an additional ten minutes, then cooled. Ethanol(5mL), 3 M sodium hydroxide solution(10mL) was added to solution. Mixture was filtered and rinsed with cold ethanol, then cold water, then took the crude weight of the product.
The solid was placed into a round bottomed flask where maleic anhydride(0.200g) and triglyme(4mL) was added. The mixture was refluxed for five minutes, and cooled. Ethanol(2mL) and 3 M sodium hydroxide solution(6mL) was added to solution. The mixture was filtered and rinsed with cold ethanol and cold water, recrystallized with methanol, filtered, dried and weighted to get final product.