Diels Alder Reaction

Rita Morales

Chem 321L

Section V03

George Gao (TA)

Using Diels-Alder Reactions to Produce Ring and Bridged-Ring Compounds:

Dimethyl Tetraphenylphthalate. A combination of tetraphenylcyclopentadienone (0.103 g, 0.268 mmol), dimethyl acetylenedicarboxylate (0.1 mL, 0.813 mmol), nitrobenzene (1. mL), and a boiling stick were placed into a small reaction tube. The contents were then brought to a gentle reflux using a sand bath and the initial dark purple color was converted to a tan color after 13 min. The tube was removed from the sand and then cooled to room temp. before ethanol (3. mL) was added. The reaction tube was placed into an ice bath and a white precipitate began to form at the bottom of the tube. The solid was vacuum filtered and washed with additional ethanol (3. mL). The product was then dried and weighed yielding dimethyl tetraphenylphthalate (0.062 g, 0.124 mmol, 46.4%).

Tetraphenylnaphthalene. A boiling chip was added to a large reaction tube containing tetraphenylcyclopentadienone (0.505 g, 1.31 mmol) and 1,2-dimethoxyethane (3. mL). Isoamyl nitrate (0.31 mL) was added dropwise through a syringe to the same tube and the mixture was heated for 4 min until it produced a gentle reflux. Concurrently, in a separate, smaller reaction tube, anthranillic acid (0.249 g, 1.82 mmol) was dissolved in 1,2-dimethoxyethane (2. mL) and this mixture was slowly added dropwise with a pipette into the soln still refluxing in the larger reaction tube. Only 1-3 drops were added at a time, and there was a noticeable loud thudding noise accompanied by thick clouds of smoke when the drops touched the refluxing mixture. The color of the new soln changed from deep, dark purple to light brown after addition of the first mL. There was less smoke will the addition of the second mL and the soln gradually became lighter in color. After complete addition, the combined soln was heated for exactly 2 min. and removed from heat. The reaction tube was then capped...