Isopropanol → 2-Chloro-9,10-dihydro-9,10-methano-9-anthracenecarboxylic acid

Participants

Reaction Conditions

Reaction Steps

A stirred solution of (9RS,10RS)-2-chloro-9,10-dihydro-9,10-methanoanthracene-9-carboxaldehyde prepared as in Example 1i (290.5 g, 1.14 moles) dissolved in acetone (5.0 L) was cooled to 10° C. and treated with Jones Reagent (950 ml, ~ 1.19 moles) over a period of 1 h. The reaction mixture was stirred overnight at room temperature, then analyzed by TLC [silica gel/methylene chloride:hexane (1:1)]. Conversion of the aldehyde (Rf =0.50) to the desired carboxylic acid (Rf =0.0-0.15) was shown to be complete. Isopropanol (150 ml) was added, and the mixture stirred for another 3 h to quench any excess Jones Reagent. The acetone supernatant was decanted away from the green-black sludge that had formed, and the sludge was washed with acetone (2×1 L). The combined acetone solutions were concentrated on the rotary evaporator to a volume of 1.5 L, then poured into ice/water (6 L) with vigorous stirring. A yellow-white gum precipitated and gradually solidified with continued stirring. The solid was collected by filtration, pulverized to a fine off-white powder in a mortar & pestle, then rewashed with cold water (2×1 L). Vacuum drying afforded the title compound as an off-white powder (304.8 g, 98.7%), mp 175°-178° C.

Provenance & Evidence