Oxygen → Aleglitazar

Participants

Reaction Steps

In a glove box (O2 content≦2 ppm), a 50-ml stainless steel autoclave was charged with 0.62 mg of [Ru(OAc)2((S)-TMBTP)] (0.0008 mmol, S/C 3′000) (prepared according to EP 1,670,792 B1; TMBTP=2,2′,5,5′-Tetramethyl-4,4′-bis(diphenylphosphino)-3,3′-bithiophene) and 5 ml of methanol. The resulting orange solution was stirred for 2 h at r.t. Then, 1.00 g of (Z)-2-methoxy-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-acrylic acid (2.30 mmol), 4 ml of methanol, 6 ml of THF and 0.06 ml of (S)-1-phenylethylamine (0.47 mmol) were added. The autoclave was sealed and the hydrogenation was run under stirring at 40° C. under 30 bar of hydrogen. After 16 h the autoclave was opened and the yellowish solution was rotary evaporated to dryness (50° C./5 mbar) to afford crude (S)-2-methoxy-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid (Acid I) as a white solid with a chemical purity of 99.7% (99.9% conversion) and an enantiomeric purity of 89%.

Provenance & Evidence