1,2-Dichloro-4-fluorobenzene → 4-(3,4-Dichlorophenoxy)-[1,4']bipiperidinyl-1'-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of potassium tert-butoxide (139.0 g, 1.24 mol) in THF (500 ml) was added a solution of the product of Step 1 (176.2 g, 0.62 mol) in THF (1000 ml). The reaction mixture was stirred 10 minutes before the additon of 3,4 dichlorofluorobenzene (122.8 g, 0.74 mol), this caused a green colouration that subsequently faded. The reaction mixture was then heated at reflux for 90 minutes. The reaction mixture was then cooled to room temperature before the addition of saturated NaHCO3 (1600 ml). The layers were separated and the organic layer stripped to leave an orange semi-solid. The solid was dissolved in DCM (1500 ml) and dried (MgSO4), filtered and the solvent removed. To the resultant solid was added methyl tert-butyl ether (MTBE) (54 ml) and iso-hexane (1000 ml) to give a slurry which was stirred overnight. The slurry was then filtered and washed with isohexane (200 ml) and the solid dried in vacuo at 50° C. to give the sub-titled compound as a pale powder, (211.6 g, 80%; MS: (M+H) 429).

Provenance & Evidence