反应详情

mixture of 3-(2-hydroxy-4-methylbenzoyl)benzoic acid (2.97 g), 2N sodium hydroxide (12.8 ml), and ethanol (25 ml) is heated under reflux for 15 minutes. Then, 1-bromohexane (4.21 g) is added to the cooled solution and the resulting mixture refluxed for 48 hours. The cooled mixture is diluted with water (100 ml) and extracted with ether (3×75 ml). The ether extracts are dried over magnesium sulfate and concentrated in vacuo to yield hexyl 3-(2-n-hexyloxy-4-methylbenzoyl)benzoate (4.56 g) as a dark brown oil. This ester is mixed with 2N sodium hydroxide (6.4 ml) and refluxed for 4 hours. The cooled reaction mixture is diluted with water (50 ml), washed with ether (25 ml) and acidified to pH 2.0 with concentrated hydrochloric acid. The product is extracted with ether (3×35 ml) and the combined extracts dried over magnesium sulfate, filtered, and concentrated in vacuo. The product is then dissolved in 2N sodium hydroxide (2.95 ml) and water is added to brink the total volume to 10 ml. This sodium salt is chromatographed on a Water's Prep 500A/LC System using the reverse phase prep pack-500/C18 column (water:acetone; 80:20). The fraction containing the major component is acidified to pH 2.0 with concentrated hydrochloric acid and extracted with ether (3×100 ml). The combined ether extracts are dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue is recrystallized from heptane to yield 3-(2-n-hexyloxy-4-methylbenzoyl)benzoic acid (1.50 g), m.p. 118° C.

1. temperaturerefluxed for 4 hours
2. customThe cooled reaction mixture
3. washwashed with ether (25 ml)
4. extractionThe product is extracted with ether (3×35 ml)
5. dry with materialthe combined extracts dried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. dissolutionThe product is then dissolved in 2N sodium hydroxide (2.95 ml)
9. additionwater is added to brink the total volume to 10 ml
10. customThis sodium salt is chromatographed on a Water'
11. additionThe fraction containing the major component
12. extractionextracted with ether (3×100 ml)
13. dry with materialThe combined ether extracts are dried over magnesium sulfate
14. filtrationfiltered
15. concentrationconcentrated in vacuo
16. customThe residue is recrystallized from heptane