تفاعل #69491
ord-b8646e3abb5748fea955e38591076796
معادلة التفاعل
المتفاعلات
الكواشف
ظروف التفاعل
المعالجة
- 1workup.STIRRINGthe mixture was stirred at room temperature overnight
- 2غسيلthe THF layers was washed with water (2×350 mL)
- 3درجة الحرارةcooled to 0° C.
- 4أخرىequipped with a bleach trap
- 5أخرىformed
- 6workup.STIRRINGThe mixture was stirred at room temperature for 3 h
- 7workup.STIRRINGwas stirred at room temperature overnight
- 8استخلاصThe aqueous phase was extracted with DCM (2×)
- 9غسيلwashed with brine
- 10تجفيفdried over MgSO4
- 11ترشيحfiltered
- 12أخرىevaporated
- 13أخرىto afford an orange solid
- 14أخرىThis solid was triturated in diethyl ether
- 15ترشيحfiltered
- 16أخرىdried
الإجراء التجريبي
To a suspension of methyl 3-acetyl-5-bromo-4-hydroxybenzoate (70 g, 243.52 mmol) in THF (700 mL) at −50° C. under nitrogen (flask equipped with a bleach trap) was added lithium bis(trimethylsilyl)amide (828 ml, 828 mmol). The dark solution was allowed to warm to −5° C. and stirred for 2 h. Carbon disulfide (22 mL, 365 mmol) was added in one portion to the solution at −20° C. then the mixture was stirred at room temperature overnight. Water (700 mL) was added, the THF layers was washed with water (2×350 mL). The aqueous phases were combined and cooled to 0° C. and quenched with H2SO4 (108 ml, 1948 mmol) in a vessel equipped with a bleach trap to neutralize the H2S formed. The mixture was stirred at room temperature for 3 h, DCM was added (700 mL) and mixture was stirred at room temperature overnight. The aqueous phase was extracted with DCM (2×). The organic phases were combined, washed with brine, dried over MgSO4, filtered and evaporated to afford an orange solid. This solid was triturated in diethyl ether, filtered and dried to give methyl 8-bromo-4-hydroxy-2-thioxo-2H-chromene-6-carboxylate (48.7 g, 63%) as a yellow/orange solid. Mass Spectrum: m/z [M+H]+=317.