Chapter 19, Problem 53P

Interpretation Introduction

Interpretation:

The mechanistic steps in acid-catalyzed cyclization reaction that takes place on heating ethyl-3-oxo-4-phenylbutanoate with concentrated sulfuric acid, leading to formation of Naphthoresorcinol, are to be written.

Concept introduction:

When a compound containing phenyl ring and carbonyl functionality, at suitable positions, is treated with concentrated sulfuric acid, an intramolecular aromatic electrophilic substitution takes place. Initial protonation of the carbonyl moiety generates the internal electrophile and the electrophilic attacks at the benzene ring that ultimately leads to the formation of naphthalene skeleton.