2,5-Dichloronitrobenzene → Escitalopram

Participants

Reaction Steps

To a solution of 6 gm of (S)-(−)-4-[4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxy-1-butyl]-3-(hydroxymethyl)benzonitrile in 60 ml tetrahydrofuran (THF) was added 4.33 gm of potassium tertiary butoxide at 0-10° C. and stirred for 30 minutes. A solution of 4.04 gm of 2,5-dichloronitrobenzene in 30 ml THF at 0-10° C. was added to it and stirred for 10-15 hours at room temperature, followed by addition of 250 ml of water. The reaction mixture was extracted with toluene, the toluene layer was washed with water and 5% sodium hydroxide solution and after acid base treatment yielded an oily product. The oil was dissolved in 16 ml of acetone at 30° C. and 1.75 gm of oxalic acid dihydrate in 8 ml acetone was added to it, stirred, cooled, filtered and dried at 60° C. to get the oxalic acid salt of (S)-(+)-1-[3-(dimethylamino) propyl]-1-(4-fluorophenyl)-1,3-dihydro-5-isobenzofuran carbonitrile.

Provenance & Evidence