The present invention discloses a process for the preparation of 5-[4-[2-[N-methyl-N-(2-pyridyl)amino]ethoxy]phenyl methyl]
thiazolidine-2,4-dione maleate (VI) comprising the steps of
Coupling 2-[N-methyl-N-(2-pyridyl)amino]
ethanol (I) and 4-fluorobenzaldehyde (II) in N,N-
dimethylformamide, isolating the coupled product 4[2-[N-methyl-N-(2-pyridyl)amino]ethoxy]
benzaldehyde (III), converting said isolated
benzaldehyde compound (III) to 5-[4-[2-[N-methyl-N-(2-pyridyl)amino]ethoxy]benzylidene]
thiazolidine-2,4-dione (IV) and purifying the same, reducing 5-[4-[2-[N-methyl-N-(2-pyridyl)amino]ethoxy]benzylidene]
thiazolidine-2,4-dione, by a novel reduction method for making 5-[4-[2-[N-methyl-N-(2-pyridyl)amino]ethoxy]phenyl methyl]thiazolidine-2,4-dione (V). This reduction method involves reacting the compound (IV) with a novel
metal legand complex and a
reducing agent, purifying the product (V) obtained by a new method reported in the present invention and converting the said thiazolidine-2,4-dione compound (V) into a pharmaceutically acceptable salt.