Ethylamine → Bimatoprost

Participants

Reaction Conditions

Reaction Steps

56 g of ethylamine (MW=45.08; 47.9 equivalents) in 24 mL of water were added to 8.08 g of crude (Z)-7 [(1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenyl-pent-1-enyl)-cyclo-pentyl]hept-5-enoic acid methylester (MW=402.54; 1 equivalents) and the resulting solution was stirred for 48 h at 23° C. The excess of ethylamine was removed by distillation in vacuo (25°, 100 mbar) after complete conversion. To the residue were added 400 mL of methylenechloride and 100 mL of water and the pH was adjusted to 1.5 by addition of 1M aqueous hydrochloric acid. After separation of the layers the organic layers were washed with 100 mL of saturated aqueous sodium bicarbonate, 100 mL of water, and 100 mL of brine. The solution was filtered and concentrated in vacuo yielding 8.33 g of oily bimatoprost crude. To the residue were added 25 mL of acetonitrile. After adding seeds the mixture was stirred for 30 minutes at ambient temperature, cooled to 0° C. and stirred for two hours at this temperature.

Provenance & Evidence