反応 #44788

反応方程式

NaOH

4-[4-(2-oxazolyl)phenoxy]benzaldehyde

methyl 4-[[(1S,4S)-2,5-diazabicyclo[2.2.1]hept-2-yl]methyl]benzoate

sodium triacetoxyborohydride

→

methyl 4-[[(1S,4S)-5-[[4-[4-(2-oxazolyl)phenoxy]phenyl]methyl]-2,5-diazabicyclo[2.2.1]hept-2-yl]methyl]benzoate

収率 100.0%

溶媒

dichloroethane

反応条件

後処理

1. 1
   その他The reaction mixture was separated
2. 2
   抽出the aqueous layer was extracted with CH2Cl2
3. 3
   洗浄The combined organic layers were washed with 0.5 M H2SO4, and MeOH
4. 4
   workup.ADDITIONwas added to the mixture until the precipitated gummy solid
5. 5
   workup.DISSOLUTIONdissolved
6. 6
   その他The layers were separated
7. 7
   温度the aqueous layer was cooled to −5 C
8. 8
   workup.ADDITIONand saturated K2CO3 was added slowly enough
9. 9
   その他ester hydrolysis
10. 10
    抽出Once the pH was 11, the solution was extracted with EtOAc (2×)
11. 11
    乾燥the combined EtOAc fractions were dried
12. 12
    濃縮concentrated

実験手順

4-[4-(2-oxazolyl)phenoxy]benzaldehyde (10.2 g, 38.5 mmol) and methyl 4-[[(1S,4S)-2,5-diazabicyclo[2.2.1]hept-2-yl]methyl]benzoate (9.9 g, 40.4 mmol, 1.05 equiv.) were dissolved in dichloroethane (200 mL). After 75 minutes, sodium triacetoxyborohydride (9.8 g, 46.1 mmol, 1.2 equiv.) was added. The reaction mixture was stirred overnight at ambient temperature. Then, 1N NaOH was added. The reaction mixture was separated and the aqueous layer was extracted with CH2Cl2. The combined organic layers were washed with 0.5 M H2SO4, and MeOH was added to the mixture until the precipitated gummy solid dissolved. The layers were separated and the aqueous layer was cooled to −5 C. and saturated K2CO3 was added slowly enough to keep the temperature below 0 C. to prevent ester hydrolysis. Once the pH was 11, the solution was extracted with EtOAc (2×), and the combined EtOAc fractions were dried and concentrated to give 19.0 g (100%) of methyl 4-[[(1S,4S)-5-[[4-[4-(2-oxazolyl)phenoxy]phenyl]methyl]-2,5-diazabicyclo[2.2.1]hept-2-yl]methyl]benzoate as the free base, which was 98% pure by HPLC; 1H NMR (300 MHz, CDCl3) δ 8.02 (d, 2H), 8.02 (d, 2H), 7.69 (d, 1H), 7.47 (d, 2H), 7.40 (d, 2H), 7.22 (d, 1H), 7.08 (d, 2H), 7.05 (d, 2H), 3.92 (s, 3H), 3.84 (d, 1H), 3.78 (d, 1H), 3.77 (d, 1H), 3.71 (d, 1H), 3.35 (s, 1H), 3.31 (s, 1H), 2.89 (d, 1H), 2.88 (d, 1H), 2.71 (dd, 1H), 2.70 (dd, 1H), 1.79 (s, 2H) ppm.

出典