[OH-].[Na+].[Cl:3][C:4]1[CH:14]=[CH:13][CH:12]=[C:11]([Cl:15])[C:5]=1[CH2:6][O:7][CH2:8][CH2:9][OH:10].[Br:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22]Br.O>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.C1(C)C=CC=CC=1>[Br:16][CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][O:10][CH2:9][CH2:8][O:7][CH2:6][C:5]1[C:4]([Cl:3])=[CH:14][CH:13]=[CH:12][C:11]=1[Cl:15]50% aq NaOH (1.89 L), 2-(2,6-dichlorobenzyloxy)ethanol (473.2 g), 1,6-dibromohexane (2.44 kg, 5 eq) and tetrabutylammonium bromide (34.1 g, 5 mol %) in toluene (1.89 L) was heated to 55-60° C. for 8-20 h. On cooling water (558 mL) and toluene (558 mL) were added. The aqueous phase was separated and diluted with water (1 L) then back extracted with toluene (1.1 L). The combined toluene extracts were washed twice with water (2.2 L), then evaporated to dryness on a rotary evaporator. The excess 1,6-dibromohexane was removed using a wiped film evaporator, and the resulting crude product chromatographed on silica (5 kg Biotage), eluting with 5% ethyl acetate in petrol 60/80, to give the title compound (503.2 g)−LC RT=7.0 min.
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