反应详情

Crude 7-{7-(3-hydroxy-3-methyl-4 -propoxybut-1-enyl)-1,4-dioxaspiro[4,4]non-6-yl}heptanoic acid [1.04 g.; prepared as hereinbefore described in Example 1 (viii)], undried acetone (50 ml.) containing a small amount of water and p-toluenesulphonic acid dihydrate (0.1 g.) were left to stand together at room temperature for 24 hours. The mixture was then added to excess diethyl ether and washed with water until the washings were neutral. The ether solution was dried over sodium sulphate and evaporated, to give crude 7-[5-(3-hydroxy-3-methyl-4-propoxybut-1-enyl)-2-oxocyclopentyl] heptanoic acid (0.83 g.). This material was purified by preparative thin layer chromatography on silica gel, using a mixture of toluene, dioxan and acetic acid (65:15:1 by volume) as eluant, to give 7-[5-(3-hydroxy-3-methyl-4-propoxybut-1-enyl)2-oxocyclopentyl] heptanoic acid (90 mg.). Elemental analysis: found C, 67.3; H, 9.9%; C20H34O5 requires C, 67.7; H, 9.7%.

1. waitwere left
2. washwashed with water until the washings
3. dry with materialThe ether solution was dried over sodium sulphate
4. customevaporated
5. customto give crude 7-[5-(3-hydroxy-3-methyl-4-propoxybut-1-enyl)-2-oxocyclopentyl] heptanoic acid (0.83 g.)
6. customThis material was purified by preparative thin layer chromatography on silica gel
7. additiona mixture of toluene, dioxan and acetic acid (65:15:1 by volume) as eluant