Boron tribromide → (R)-5-Hydroxy-3-(N-isopropyl-N-n-propylamino)chroman

HRID 2257369Notes

Reaction equation

[CH:1]([N:4]([C@@H:8]1[CH2:17][C:16]2[C:11](=[CH:12][CH:13]=[CH:14][C:15]=2[O:18]C)[O:10][CH2:9]1)[CH2:5][CH2:6][CH3:7])([CH3:3])[CH3:2].B(Br)(Br)Br.C([O-])(O)=O.[Na+]>C(Cl)Cl>[OH:18][C:15]1[CH:14]=[CH:13][CH:12]=[C:11]2[C:16]=1[CH2:17][C@@H:8]([N:4]([CH:1]([CH3:2])[CH3:3])[CH2:5][CH2:6][CH3:7])[CH2:9][O:10]2

Participants

Conditions

Temperature: -60 °C

Procedure

The HCl-salt of (R)-3-(N-isopropyl-N-n-propylamino)-5-methoxychroman (15.5 g, 52 mmol) was mixed with CH2Cl2 (100 mL) under nitrogen atmosphere and cooled to -60° C. BBr3 (27.2 g, 110 mmol) dissolved in CH2Cl2 (50 mL), was added slowly. The temperature was then raised to 0° C. and the reaction mixture was stirred at 0° C. for 12 h. The reaction mixture was then slowly added to a stirred saturated NaHCO3 solution. The layers were separated and the water layer was extracted once with CH2Cl2. The combined organic layers were dried (MgSO4). Removal of the solvent in vacuo gave the phenolic title compound. Yield: 98%. [α]D22 (Base)=-83.0° (C=0.1;MeOH).Mp(HCl-salt): 215°-222° C. (decomposes).

Workup

additionwas added slowly
temperatureThe temperature was then raised to 0° C.
customThe layers were separated
extractionthe water layer was extracted once with CH2Cl2
dry with materialThe combined organic layers were dried (MgSO4)
customRemoval of the solvent in vacuo

Sources & evidence

ORD record: ord-3d3b21b8b170495da599f2322a3e5a1c
Source dataset: uspto-grants-1997_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05656658

Reaction notes

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