Triphenylphosphine → [Rac]-2-isopropoxy-3-{3-methoxy-4-[2-(5-methyl-2-p-tolyl-thiazol-4-yl)-ethoxy]-phenyl}-propionic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

In analogy to the procedure described in example 1 d], [rac]-3-(4-hydroxy-3-methoxy-phenyl)-2-isopropoxy-propionic acid ethyl ester [prepared from isopropoxy-acetic acid ethyl ester (Tetrahedron (1982), 38(17), 2733-9) and 4-benzyloxy-3-methoxy-benzaldehyde in analogy to the procedures described in examples 54 a]to c)] was reacted with 2-(5-methyl-2-p-tolyl-thiazol-4-yl)-ethanol (prepared from [rac]4-bromo-3-oxo-pentanoic acid methyl ester [PCT Int. Appl. (2001), WO 01/79202] and 4-methyl-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]-2-isopropoxy-3-{3-methoxy-4-[2-(5-methyl-2-p-tolyl-thiazol-4-yl]-ethoxy}-phenyl)-propionic acid ethyl ester, which was further saponified in analogy to the procedure described in example 4 e], to yield [rac]-2-isopropoxy-3-{3-methoxy-4-[2-(5-methyl-2-p-tolyl-thiazol-4-yl)-ethoxy]-phenyl}-propionic acid as colorless amporphous solid.

Herkunft & Nachweise