Carbon Dioxide → Win 54954

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of milled potassium carbonate (172.5 gm, 1.25 moles) in 1.35 L dimethylformamide (DMF) was added 2,6-dichloro-4-(4,5-dihydro-2-oxazolyl)phenol hydrochloride (133.5 gm, 0.5 moles). Heavy gas evolution (CO2) occurred and the reaction was warmed on the steam bath to 70° C. After stirring for about 5 minutes, 5-(5-bromopentyl)-3-methylisoxazole (121.8 gm, 0.525 moles) was added in one portion. The mixture was heated to 90°-95° C. for 1 hr, allowed to cool to room temperature and then filtered. The filter cake was rinsed with DMF and the filtrate was concentrated under water vacuum to a viscous brown oil (260 gm). This residue was dissolved in 300 ml isopropyl acetate and washed with water and then with brine. The organic layer was dried over MgSO4, charcoaled, filtered and evaporated to dryness. The crude product (220 gm oil) was diluted with 287 ml acetone (1.5 volumes based on theoretical yield) and was cooled and stirred in a Dry Ice/acetone bath to -25° C. The product was collected and air dried to give 115 gm (60% yield) of 5-{5-[2,6-dichloro-4-(4,5-dihydro-2-oxazolyl)phenoxy]pentyl}-3-methylisoxazole, m.p. 38°-40° C. A sample when recrystallized from triethylamine had the m.p. 42°-43° C.

Provenance & Evidence