Boron tribromide → HCID 53847727, compound

HRID 266642Notes

Reaction equation

HRID 266642 reaction equation
B(Br)(Br)Br.Cl.[F:6][C:7]1[CH:8]=[CH:9][C:10]([O:26]C)=[C:11]2[C:16]=1[O:15][CH2:14][C@H:13]([N:17]([CH:21]([CH2:24][CH3:25])[CH2:22][CH3:23])[CH2:18][CH2:19][CH3:20])[CH2:12]2>C(Cl)Cl>[F:6][C:7]1[CH:8]=[CH:9][C:10]([OH:26])=[C:11]2[C:16]=1[O:15][CH2:14][C@H:13]([N:17]([CH:21]([CH2:22][CH3:23])[CH2:24][CH3:25])[CH2:18][CH2:19][CH3:20])[CH2:12]2

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 67703428HCID 67703428, compound

Product 1

HCID 53847727HCID 53847727, compoundYield 98.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
0 °C

Procedure

Demethylation was done by addition of BBr3 (2.6 ml, 27.5 mmol) in 10 ml dry CH2Cl2 during 20 min., to a stirred, cooled solution (-70° C.) of (R)-8-fluoro-5-methoxy-3-(N-3-pentyl-N-n-propylamino)chroman hydrochloride (4.44 g, 12.8 mmol) in 100 ml dry CH2Cl2 under N2 atmosphere and dry conditions. The solution was stirred for 1 hour at -70° C., 1 hour at 0° C. and 1 hour at room temp. and was thereafter poured into 80 ml saturated NaHCO3 aq. under vigirous stirring. After 0.5 hour the layers where separated and the aqueous phase was extracted with 2×150 ml CH2Cl2. The combined organic layers where dried (Na2SO4) and evaporated. The crude product was purified by flash chromatography on silica with a gradient of petroleumether-petroleumether: EtOAc, 4:1 to give 3.72 g of (R)-8-fluoro-5-hydroxy-3-(N-3-pentyl-N-n-propylamino)chroman (NAG 134) as an yellow-brown oil. [α]D22 -85° (c 1.02 in MeOH).

Workup

  1. customdry conditions
  2. additionwas thereafter poured into 80 ml saturated NaHCO3 aq. under vigirous stirring
  3. customAfter 0.5 hour the layers where separated
  4. extractionthe aqueous phase was extracted with 2×150 ml CH2Cl2
  5. dry with materialThe combined organic layers where dried (Na2SO4)
  6. customevaporated
  7. customThe crude product was purified by flash chromatography on silica with a gradient of petroleumether-petroleumether

Sources & evidence

ORD record
ord-948c522809ba4c24bb39c0e68641af3e
Source dataset
uspto-grants-1997_07
Patent number
US05650524

Reaction notes

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