反応 #12011

反応方程式

sodium hydroxide

(R)-6-bromo-4-methyl-3,4-dihydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

sodium carbonate

trimethylboroxine

→

desired product

収率 71.1%

(R)-4,6-Dimethyl-3,4-dihydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

収率 71.1%

溶媒

1,2-dimethoxyethane

THF

反応条件

後処理

1. 1
   温度the resulting suspension was heated
2. 2
   温度to reflux for 5 h
3. 3
   抽出extracted three times with ethyl acetate
4. 4
   洗浄The combined organic layers were washed with brine
5. 5
   乾燥dried over magnesium sulfate
6. 6
   ろ過filtered
7. 7
   その他evaporated
8. 8
   その他The residue was purified by flash column chromatography on silica gel (0.032–0.063 mm) with ethyl acetate:n-hexane (1:1) as eluant

実験手順

To a solution of 0.20 g (0.55 mmol) (R)-6-bromo-4-methyl-3,4-dihydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester (Example 5, intermediate a) in 10 ml 1,2-dimethoxyethane was added 63 mg (55 μmol) tetrakis(triphenylphosphine)palladium. After 30 min, 5 ml saturated aqueous sodium carbonate solution and 0.09 ml (0.65 mmol) of a 1M trimethylboroxine solution in THF were added and the resulting suspension was heated to reflux for 5 h. The reaction mixture was cooled to room temperature, poured into 20 ml 1M aqueous sodium hydroxide solution and extracted three times with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered and evaporated. The residue was purified by flash column chromatography on silica gel (0.032–0.063 mm) with ethyl acetate:n-hexane (1:1) as eluant to yield the desired product as a yellow solid (71.1%).

出典