p-Toluenesulfonic acid → [Rac]-2-[1-methyl-3-oxo-3-(4-trifluoromethyl-phenyl)-(z)-propenylamino]-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid ethyl ester

Participants

Reaction Steps

In analogy to the procedure described in example 105 a], [rac]-2-amino-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid ethyl ester was reacted with 1-(4-trifluoromethyl-phenyl)-butane-1,3-dione in toluene in the presence of a catalytic amount of p-toluene sulfonic acid at reflux to yield [rac]-2-[1-methyl-3-oxo-3-(4-trifluoromethyl-phenyl)-(Z)-propenylamino]-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid ethyl ester, which was further saponified in analogy to the procedure described in example 105 b] to yield [rac]-2-[1-methyl-3-oxo-3-(4-trifluoromethyl-phenyl)-(Z)-propenylamino]-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid as light yellow solid.

Provenance & Evidence