Triphenylphosphine → [Rac]-3-(4-{2-[2-(3,5-dimethyl-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-3-methoxy-phenyl)-2-isopropoxy-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-[2-(3,5-dimethyl-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 3,5-dimethyl-thiobenzamide (from 3,5-dimethyl-benzonitrile and NaSH, NH4Cl in N,N-dimethylformamide) 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-(3,5-dimethyl-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-3-methoxy-phenyl)-2-isopropoxy-propionic acid ethyl ester, which was farther saponified in analogy to the procedure described in example 4 e], to yield [rac]-3-(4-{2-[2-(3,5-dimethyl-phenyl)-5-methyl-thiazol-4-yl]-ethoxy}-3-methoxy-phenyl)-2-isopropoxy-propionic acid as light yellow solid.

Herkunft & Nachweise