Boron tribromide → 5-Carbamoyl-4-hydroxy-1-chlorocarbazole

HRID 567361Notes

Reaction equation

HRID 567361 reaction equation
C([N:8]1[C:20]2[C:19]([Cl:21])=[CH:18][CH:17]=[C:16]([O:22]C)[C:15]=2[C:14]2[C:9]1=[CH:10][CH:11]=[CH:12][C:13]=2[C:24](=[O:26])[NH2:25])C1C=CC=CC=1.B(Br)(Br)Br>ClCCl>[C:24]([C:13]1[CH:12]=[CH:11][CH:10]=[C:9]2[C:14]=1[C:15]1[C:16]([OH:22])=[CH:17][CH:18]=[C:19]([Cl:21])[C:20]=1[NH:8]2)(=[O:26])[NH2:25]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 22739100HCID 22739100, compound

Product 1

HCID 227381395-Carbamoyl-4-hydroxy-1-chlorocarbazoleYield 80%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of 0.66 g of 9-benzyl-5-carbamoyl-4-methoxy-1-chlorocarbazole in 40 ml of dichloromethane was cooled in an ice bath treated dropwise with 14 ml of 1.0 M boron tribromide solution in dichloromethane. The reaction was allowed to warm to room temperature slowly over 2 hours and then quenched by pouring into ice and then adding 50 ml of 1 N HCl. The mixture was extracted with dichloromethane (3×200 ml) and the extracts were washed with brine, dried with magnesium sulfate and concentrated. The aqueous layers exhibited a precipitate and was then extracted twice with ethyl acetate, washed with brine, dried with magnesium sulfate and concentrated to afford 0.287 g of the subtitle compound. The first residue was chromatographed on silica gel using 0.5% methanol in dichloromethane to afford another 93 mg of the subtitle compound. (total yield 80%) ESIMS m/e 259 (M+−1) NMR (300 MHz, d6-DMSO): δ 11.79 (s, 1H); 10.76 (s, 1H); 8.87 (br s, 1H); 8.41 (br s, 1H); 7.77 (t, J=4.6, 1H); 7.48 (d, J=4.2, 2H); 7.34 (d, J=8.5, 1H); 6.54 (d, J=8.5, 1H).

Workup

  1. customquenched
  2. additionby pouring into ice
  3. additionadding 50 ml of 1 N HCl
  4. extractionThe mixture was extracted with dichloromethane (3×200 ml)
  5. washthe extracts were washed with brine
  6. dry with materialdried with magnesium sulfate
  7. concentrationconcentrated
  8. extractionwas then extracted twice with ethyl acetate
  9. washwashed with brine
  10. dry with materialdried with magnesium sulfate
  11. concentrationconcentrated

Sources & evidence

ORD record
ord-e0e8d12209f84b7ca5f9c40c5834007d
Source dataset
uspto-grants-2001_01
Patent number
US06177440B1

Reaction notes

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