Sodium Methoxide → rac-(E)-3-[2-hydroxy-6-[6-[(tetrahydro-2H-pyran-2-yl)oxy]-1-hexynyl]phenyl]-2-propenoic acid methyl ester
Reaction equation
[O:1]1[CH2:6][CH2:5][CH2:4][CH2:3][CH:2]1[O:7][CH2:8][CH2:9][CH2:10][CH2:11][C:12]#[C:13][C:14]1[C:19]2[CH:20]=[CH:21][C:22](=[O:24])[O:23][C:18]=2[CH:17]=[CH:16][CH:15]=1.[CH3:25][O-:26].[Na+]>CO>[CH3:25][O:26][C:22](=[O:24])/[CH:21]=[CH:20]/[C:19]1[C:14]([C:13]#[C:12][CH2:11][CH2:10][CH2:9][CH2:8][O:7][CH:2]2[CH2:3][CH2:4][CH2:5][CH2:6][O:1]2)=[CH:15][CH:16]=[CH:17][C:18]=1[OH:23]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of 1.09 g (3.3 mmol) of rac-5-[6-[(tetrahydro-2H-pyran-2-yl)oxy]-1-hexynyl]-2H-1-benzopyran-2-one and 1.8 mL (7.9 mmol) of 25% methanolic sodium methoxide in 5 mL of methanol was stirred and refluxed for 24 hr and then concentrated under reduced pressure. The residue was treated with 1N hydrochloric acid and worked-up with ethyl acetate in the usual manner (the organic extracts were additionally washed with saturated aqueous sodium bicarbonate). The residue was purified by flash chromatography on silica gel, eluting with 2:1 hexane-ether. There was obtained 0.7 g (59%) of rac-(E)-3-[2-hydroxy-6-[6-[(tetrahydro-2H-pyran-2-yl)oxy]-1-hexynyl]phenyl]-2-propenoic acid methyl ester as a yellow oil. Trituration of a sample prepared in this way with hexane gave a colorless solid, mp 66°-67.5° C.