Multistep synthesis of 4-[2-(dipropylamino)-etyhl]-1,3-dihydro-2H-indol-2-one hydrochloride (ropinirole hydrochloride) was elaborated in Pharmaceutical Research Institute. From ten steps of synthesis - reduction of starting 2-methyl-3-nitrobenzoic acid to the corresponding alcohol, reaction of chain extension and reductive cyclization to indolone ring play significant role in the process of the formation find product.

Development of synthetic steps one to four was based on the literature data [1] and steps five to ten were carried out according to the patent procedure [2].

References

1. Bhaskar Kanth J.V., Periasamy M., J. Org. Chem. 1991, 56, 5964-5965.

2. Patent EP 113964 (1982).