Boron tribromide → 2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol

HRID 856943

反応式

HRID 856943 の反応式
C[O:2][C:3]1[CH:12]=[C:11]2[C:6]([CH2:7][CH2:8][C:9]([CH3:14])([CH3:13])[O:10]2)=[CH:5][CH:4]=1.B(Br)(Br)Br.C([O-])(O)=O.[Na+]>ClCCl>[CH3:13][C:9]1([CH3:14])[CH2:8][CH2:7][C:6]2[C:11](=[CH:12][C:3]([OH:2])=[CH:4][CH:5]=2)[O:10]1

参加物

5

反応物 3

HCID 25134Boron tribromideHCID 516892Sodium BicarbonateHCID 108563167-Methoxy-2,2-dimethyl-chroman

生成物 1

HCID 110412812,2-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol収率 42%

試薬・触媒・溶媒 1

HCID 6344Dichloromethane溶媒

実験手順

To a stirred solution of 7-Methoxy-2,2-dimethyl-chroman (4.55 g, 23.7 mmol, from step 1) in anhydrous dichloromethane (50 mL) was added 1M BBr3 (72.86 mL, 47.4 mmol, 2.0 eq) via cannula over 10 min. The resulting dark brown solution was stirred at rt for 17 h. Saturated solution of NaHCO3 (50 mL) was added and extracted with CH2Cl2 (3×50 mL. The combined organic layers were dried over Na2SO4, filtered and evaporated. The residue was purified on silica gel (flash column chromatography) eluting with 5% ethyl acetate-hexane followed by 20% ethyl acetate-hexane to provide the desired product as white solid (1.76 g, 42%). 1H-NMR (CD3CN) δ 6.89 (d, J=8.5 Hz, 1H), 6.68 (broad, s, 1H, OH), 6.31 (dd, J=2.4, 8.5 Hz, 1H), 6.15 (d, J=2.4 Hz, 1H), 2.69 (t, 2H), 1.79 (t, 2H), 1.31 (s, 6H). MS LC-MS (MH+=179).

後処理

  1. extractionextracted with CH2Cl2 (3×50 mL
  2. dry with materialThe combined organic layers were dried over Na2SO4
  3. filtrationfiltered
  4. customevaporated
  5. customThe residue was purified on silica gel (flash column chromatography)
  6. washeluting with 5% ethyl acetate-hexane

出典と根拠

ORDレコード
ord-22d881df84794970a63c9898587c5e27
出典データセット
uspto-grants-2006_12
特許番号
US07144885B2

関連ノート

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