反応 #2175449

反応方程式

2,7-di(Boc-amino)fluorene

THF

→

9-formyl-2,7-di(Boc-amino)fluorene

溶媒

ethyl formate

反応条件

後処理

1. 1
   その他(Note: ethyl formate was stored over K2CO3 to remove formic acid.) The solution
2. 2
   温度was cooled in an ice bath
3. 3
   workup.ADDITIONsodium hydride 60% in mineral oil was added portion-wise (5.5 eq, 69 mmol, 2.75 g)
4. 4
   温度heated to 50° C.
5. 5
   その他after fitting with a reflux condenser
6. 6
   温度the reaction was cooled in an ice bath
7. 7
   その他quenched by the slow addition of deionized water (50 mL)
8. 8
   抽出extracted with ethyl acetate (2×400 mL)
9. 9
   乾燥The combined organic layers were dried with Na2SO4
10. 10
    ろ過filtered
11. 11
    その他evaporated under reduced pressure
12. 12
    その他The crude product (dark brown solid) was purified by flash chromatography
13. 13
    洗浄silica gel 60 Å step-wise gradient elution 1-5% methanol in chloroform
14. 14
    その他Yield (4.8 g, ˜90%) of a yellow to brown solid

実験手順

Purified 2,7-di(Boc-amino)fluorene (5 g, 12.5 mmol) (prepared from step A, above), was dissolved in ethyl formate (50 mL) and anhydrous THF (60 mL) with gentle heating. (Note: ethyl formate was stored over K2CO3 to remove formic acid.) The solution was cooled in an ice bath and sodium hydride 60% in mineral oil was added portion-wise (5.5 eq, 69 mmol, 2.75 g). The reaction was slowly warmed to room temperature and then heated to 50° C. after fitting with a reflux condenser. After two hours, the reaction was cooled in an ice bath and quenched by the slow addition of deionized water (50 mL). The aqueous layer was adjusted to pH 5 with glacial acetic acid and extracted with ethyl acetate (2×400 mL). The combined organic layers were dried with Na2SO4, filtered and evaporated under reduced pressure. The crude product (dark brown solid) was purified by flash chromatography: silica gel 60 Å step-wise gradient elution 1-5% methanol in chloroform. Yield (4.8 g, ˜90%) of a yellow to brown solid, depending on purity. 1H-NMR (d6-DMSO): δ (ppm) 11.0 (s, 0.9H, enol); 9.3 (2 s, 1.9H, NH urethane); 7.2-8.3 (m, Ar, C10 H enol); 6.5 (2 s, 0.1H, NH urethane); 4.1 (m, 0.3H, CH); 1.5 (s, 18H, Boc).

出典