A convenient synthesis of 4-(2-hydroxyethyl)indolin-2-one, a useful intermediate for the preparation of both dopamine receptor agonists and protein kinase inhibitors

This paper describes a practical approach to the preparation of 4-(2-hydroxyethyl)indolin-2-one, a key intermediate in the synthesis of dopaminergic agonists such as ropinirole—a drug used in the treatment of Parkinson’s disease and restless legs syndrome—and of two sets of protein kinase inhibitors. The sequence starts from commercially available 2-(2-methyl-3-nitrophenyl)acetic acid, which is converted in five steps into the desired target compound. This procedure offers a convenient alternative route to existing methodologies, given its milder reaction conditions, ease of implementation, and its overall yield (59 %).