Hydrochloric Acid → 3,5-Dichloro-4-(4-chlorobenzoyl)benzyl alcohol

Participants

Reaction Steps

Concentrated aqueous HCl (25 ml) is added to the above reaction mixture, which is allowed to warm to room temperature and aged for 12 hours. The reaction is monitored by silica gel TLC eluted with 10% EtOAc in hexane (Rf 5: 0.03). Upon completion the reaction mixture is partitioned between EtOAc (100 ml) and cold H2O (300 ml) and the layers are separated. The organic layer is washed with H2O (150 ml), 1N aqueous NaOH (2×150 ml, thoroughly to remove 4-chlorobenzoic acid), H2O (150 ml), and 0.1 N aqueous HCl. The organic layer is dried (Na2SO4), filtered, and concentrated to give crude crystalline 3,5-dichloro-4-(4-chlorobenzoyl)-benzyl alcohol, 5 (9.97 g), 60 weight percent pure (70% assay yield from alcohol 2) by HPLC assay on DuPont Zorbax ODS-C8 eluted isocratically at ambient temperature at 2 ml/min with 55% H2O, 45% CH3CN, and 0.1% H3PO4 and monitored by UV detection at 230 mn (retention times, alcohol 2: 5.1min; benzophenone 5: 14.4 min; 4-chlorobenzoic acid: 2.9 min).

Provenance & Evidence