| abstract |
A process for preparing a compound having PGD 2 antagonism represented by the formula (I), or a pharmaceutically acceptable salt or hydrate thereof, which process comprises reacting an amino alcohol of the formula (II) or its salt with a compound of the formula (III) or its reactive derivative, oxidizing the product with halo oxoacid in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyls, reacting the product with an ylide under the conditions for Wittig reaction, and optionally deprotecting the product. |