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The synthesis of phenacetin involves an SN2 reaction between acetaminophen's phenol (nucleophile) and ethyl iodide (electrophile). The reaction is facilitated by potassium carbonate, a non-nucleophilic base, in acetonitrile solvent under refluxing conditions.
Fun behind-the-scenes info: CHEM 146A students optimized this reaction from the literature procedure, including the choice of solvent, amount & identity of base, and source of starting material. Tylenol was originally used in the reaction, however, using pure acetaminophen provided better yields.
chemistrysteps.com/sn2-nucleophilic-substitution
Recall we want good overlap with bonding orbitals and this only happens when the Nuc attacks from the backside opposed to the frontside where a node is.
Discuss/Imagine:
"You're in 146a and Dr. Binder demands that your group must optimize this reaction by changing the identity of the base. Out of fear, your group-mate blurts out 'using potassium methoxide as a base!' Another suggests potassium cyanide as the base before having a breakdown. You being the savvy chemist who doesn't let Dr. Binder scare you, isn't sure if these are good suggestions."
Are these better suggestions than potassium carbonate? Discuss.
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