Triphenylphosphine → [Rac]-3-(4-{2-[2-(4-chloro-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-5-ethoxy-2-fluoro-phenyl)-2-ethoxy-propionic acid ethyl ester

Participants

Reaction Steps

In analogy to the procedure described in example 4 d], [rac]-2-ethoxy-3-(5-ethoxy-2-fluoro-4-hydroxy-phenyl)-propionic acid ethyl ester [example 68 a]] was reacted with 2-[2-(4-chloro-phenyl)-5-methyl-thiazol-4-yl]-ethanol (prepared from [rac]-4-bromo-3-oxo-pentanoic acid methyl ester [PCT Int. Appl. (2001), WO 01/79202] and 4-chloro-thiobenzamide in analogy to the procedures described in examples 12 a] and 12 b]) in tetrahydrofuran in the presence of triphenylphosphine and DEAD (diethyl azodicarboxylate) to yield [rac]-3-(4-{2-[2-(4-chloro-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-5-ethoxy-2-fluoro-phenyl)-2-ethoxy-propionic acid ethyl ester, which was further saponified in analogy to the procedure described in example 4 e], to yield [rac]-3-(4-{2-[2-(4-chloro-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-5-ethoxy-2-fluoro-phenyl)-2-ethoxy-propionic acid as light yellow solid.

Provenance & Evidence