To a stirred solution of 5-benzyloxy-2-(2,3-dichlorobenzyl)-6-hydroxypyrimidine-4-carboxylic acid (131) (5.5 g, 13.58 mmol) in tetrahydrofuran (70 mL) were added N,N-diisopropylethylamine (9.36 mL, 54.32 mmol) and T3P (17.3 mL, 27.16 mmol) followed by [2-(tert-butyl-dimethylsilanyloxy)-ethyl]-isopropyl-amine (8b) (5.89 g, 27.16 mmol) at room temperature. The mixture was heated at 65° C. for 4 h. After completion of the reaction, water was added and the mixture was extracted with ethyl acetate. The separated organic part was dried and concentrated to get a crude product which was purified by a normal silica column using 10 to 20% ethyl acetate in hexane to obtain 5-benzyloxy-2-(2,3-dichlorobenzyl)-6-hydroxypyrimidine-4-carboxylic acid [2-(tert-butyl-dimethylsilanyloxy)-ethyl]isopropylamide (132) (2.7 g, 32.8%) as a light yellow solid.
