Abstract: The invention relates in particular to a process for the preparation of a compound of formula (I) wherein R1 and R2 are as defined in the description and in the claims.

Abstract: Novel processes for the preparation of peripheral opioid antagonist compounds and intermediates thereto. The compounds prepared by the present processes may be useful, for example, as antagonists to the mu, kappa and delta opioid receptors, and thereby may be useful in the treatment of gastrointestinal motility disorders, and in preventing peripheral opiate induced side effects. The present processes may offer improved yields, chemical or stereochemical purity, ease of preparation and/or isolation of intermediates and final product, and more industrially useful reaction conditions and workability.