Chlorodifluoromethane → 1-Bromo-3-cyclopropylmethoxy-4-difluoromethoxybenzene

Participants

Reaction Conditions

Reaction Steps

A mixture of crude 4-bromo-2-cyclopropylmethoxyphenol (388 g) and (n-Bu)4NBr (20 g) in dioxane (2.0 L) was heated to 65° C. Aqueous caustic solution (40%, 294 g) was added and the temperature was raised to 80° C. Chlorodifluoromethane was added below the surface via a 12 gauge needle and CF2HCl was rapidly absorbed. After about 70 minutes, the absorption of gas ceased and reaction temperature dropped to 77° C. About 184 g of chlorodifluoromethane (Fw=86.47, 2.128 mol) had been added. GC analysis of an aliquot indicated the disappearance of the starting material. The mixture was cooled to room temperature and was quenched with water (1.2 L) under CF2HCl atmosphere. Extraction with hexanes (2×750 mL) and the combined hexanes extracts were washed with water (1 L). The aqueous layer was back-extracted with hexanes (500 mL) and the combined organic extracts were dried (MgSO4) and filtered. Evaporation of the solvent under reduced pressure gave a brown oil (about 457 g). GC analysis showed 75 area % purity. The crude yield was 98% or 86% adjusted to GC area %. The crude product was distilled over a 5-plate, Older-Shaw column at 1.0 mm-Hg at 107-113° C. (overhead). Results and conditions are given in Table 3.

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