Disclosed herein is a process for the preparation of a compound of formula (I) and derivatives (I-A) and (I-B), wherein the substituents are as defined within the specification, comprising the steps of: reacting a compound of formula (V) with a reducing agent system； in a solvent； at a temperature in the range of from about 0°C to 25°C, to yield a compound of formula (VI)； followed by reacting a compound of formula (VI) with a compound of formula (VII) in the presence of an oxidizing agent system, in a solvent, at a temperature in the range of from about 20°C to 100°C to afford the compound of formula (I).
