Sodium Carbonate → HCID 20194907、化合物
反応式
O[CH:2]1[CH2:7][O:6][CH:5]([C:8]([O:10]CC)=[O:9])[CH2:4][CH2:3]1.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)([O-])[O-].[Na+].[Na+]>C1(C)C=CC=CC=1>[CH:2]12[CH2:3][CH2:4][CH:5]([O:6][CH2:7]1)[C:8](=[O:9])[O:10]2参加物
5
実験手順
A mixture of the cis and trans isomers of ethyl 5-hydroxytetrahydropyran-2-carboxylate (3.9 g, 0.023 mol) was dissolved in dry toluene (200 ml). p-Toluene-sulfonic acid monohydrate (0.20 g, 1.1 mmol) was added as a catalyst. The mixture was refluxed for 7 hours through a Soxhlet extractor containing molecular Type A sieves in a thimble. The mixture was cooled to room temperature, and anhydrous sodium carbonate (5 g) was added to neutralize the acid. The solution was passed through a short pad of silica gel and concentrated. A brown viscous oil was subjected to column chromatography (column, silica gel; eluent, n-hexane/ethyl acetate, 1:1 v/v). The crude product thus isolated was purified by repeated recrystallization from a mixture of ethyl ether and n-hexane (5-20:1 v/v). The lactone has a melting point of 56°-57° C.