The condensation of 2-methoxyphenol (I) with 2-bromoethanal dimethylacetal (II) by means of K2CO3 in hot DMF gives 2-(2-methoxyphenoxy)ethanal dimethylacetal (III), which is hydrolyzed to the corresponding free aldehyde (IV) with 2N H2SO4 in methanol. The cyclization of (IV) with cysteamine (V) by means of potassium acetate in water affords 2-(2-methoxyphenoxymethyl)thiazolidine (VI), which is finally condensed with ethoxymalonyl chloride (VII) by means of KHCO3 in ethyl acetate.