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

HRID 131161

反応式

HRID 131161 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=2.4Hz, 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-ca1bbde6e1a848948f3665919bc6fdbb
出典データセット
uspto-grants-2008_06
特許番号
US07384947B2

関連ノート

読み込み中…