Potassium tert-butoxide → Bimatoprost

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

(5-(Ethylamino)-5-oxopentyl)triphenylphosphonium bromide 96 (1.37 g, 2.91 mmol, 6 eq.) was added to a flame dried Schlenk flask, under N2, and anhydrous THF (10 ml) added. The resulting suspension was cooled to 0° C. KOt-Bu (653.0 mg, 5.82 mmol, 12 eq.) was added in one portion and the resulting orange mixture stirred at 0° C. for 40 min. A solution of crude triol 94 (0.485 mmol, 1 eq.) in anhydrous THF (2.5 ml) was added dropwise via syringe. After complete addition the mixture was stirred at r.t. for 1 h. The reaction was quenched with saturated aq. NH4Cl (10 ml) and extracted with EtOAc (5×10 ml). The combined organic phases were dried (MgSO4), filtered, and concentrated to give the crude material as solids. These were triturated with EtOAc (10 ml) and the solids filtered and washed with EtOAc (4×10 ml). The filtrate was concentrated under vacuum and purified by column chromatography on silica, eluting with EtOAc/MeOH (97.5:2.5 to 95:5) to give 97 (99.2 mg) as a yellowish oil which was further purified by preparative TLC (EtOAc/MeOH 5%) to give 97 (82.6 mg, 41% over 2 steps) as a clear, colourless oil. Analytical data consistent with the literature (Zanoni, G. et al., Tetrahedron 66, 7472-7478 (2010); Gutman, A. et al., US 20090163596 (2009)).

Herkunft & Nachweise