Acetic Acid → Methyl 5,6-dihydro-2H-thiopyran-3-carboxylate
反応式
[S:1]1[CH2:6][CH2:5][CH:4]=[C:3]([C:7]([O-:9])=[O:8])[CH2:2]1.B(O[O-])=O.[Na+].O.[OH-].[Na+].[C:18](O)(=O)C>>[S:1]1[CH2:6][CH2:5][CH:4]=[C:3]([C:7]([O:9][CH3:18])=[O:8])[CH2:2]1[S:1]1[CH2:6][CH2:5][CH:4]=[C:3]([C:7]([O-:9])=[O:8])[CH2:2]1.B(O[O-])=O.[Na+].O.[OH-].[Na+].[C:18](O)(=O)C>>[S:1]1[CH2:6][CH2:5][CH:4]=[C:3]([C:7]([O:9][CH3:18])=[O:8])[CH2:2]1To a solution of 0.934 gm (5.75 mmol) of 5,6-dihydro-2H-thiopyran-3-carboxylate from part C in glacial acetic acid (40 mL) was added 1.98 gm (12.88 mmole) sodium perborate. The reaction mixture was stirred at 55° C. under N2 for 19 hrs. whereupon the solution was poured into H2O (50 mL) and neutralized with 50% NaOH to pH=7. The solution was extracted three times with methylene chloride. The combined organic layers were washed once with saturated sodium bicarbonate and once with saturated sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo to give 0.832 gm (76%) of methyl 5,6-dihydro-2H-thiopyran-3-carboxylate, 1,1 dioxide as a white solid; mass spectrum m/e=190 (EI, M+) Part E: Preparation of Methyl-2H-thiopyran-3-carboxylate, 1,1-dioxide.
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