Water → HCID 15078774, compound

Participants

Reaction Steps

A suspension of squaric acid (23.3 g, 0.20 mole) in cyclohexanol (80 mL, 77 g, 0.77 mole) and toluene (120 mL) was refluxed with continuous collection of water in a Dean-Stark separator. After three hours reflux, the solution was homogeneous and the theoretical amount of water had been collected. The solution was washed with water (100 mL). To the stirred toluene solution of squarate ester was added methanol (100 mL) and triethylamine (58 mL) and then bromopropylamine hydrobromide (42.2 g, 0.193 mole) in 100 mL of methanol over 0.5 hour. After the addition was complete, the reaction was stirred an additional 0.5 hour and then concentrated under reduced pressure at 45° C. (aspirator pressure) to ca. 1/4 volume. The resulting thick slurry was diluted with 500 mL water and filtered to isolate a crude, off-white solid. This was recrystallized from 1:1 toluene:hexane (300 mL) to give 45.3 g (74.5% yield) of the title compound as a pale yellow powder, m.p. 68°-70° C.

Provenance & Evidence