Azobisisobutyronitrile → 4,9-Dibromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester

HRID 575049Notes

Reaction equation

HRID 575049 reaction equation
[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]2[CH2:8][CH2:9][O:10][C:11]3[CH:18]=[CH:17][C:16]([Br:19])=[CH:15][C:12]=3[C:13]=2[N:14]=1)=[O:4].CC(N=NC(C#N)(C)C)(C#N)C.C1C(=O)N([Br:39])C(=O)C1>C(Cl)(Cl)(Cl)Cl>[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]2[CH:8]([Br:39])[CH2:9][O:10][C:11]3[CH:18]=[CH:17][C:16]([Br:19])=[CH:15][C:12]=3[C:13]=2[N:14]=1)=[O:4]

Participants

5

Reactant 3

HCID 6547AzobisisobutyronitrileHCID 67184N-bromobutanimideHCID 86693083Methyl 9-bromo-4,5-dihydro-[1]benzoxepino[5,4-d]thiazole-2-carboxylate

Product 1

HCID 866930844,9-Dibromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl esterYield 94.1%

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

To a stirred mixture of 9-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester (5 g, 14.70 mmol) in CCl4 (100 mL) was added AIBN (0.24 g, 1.46 mmol) and NBS (2.88 g, 16.18 mmol). The mixture was heated to reflux overnight. Then the mixture was partitioned between EtOAc and H2O. The aqueous layer was extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered, concentrated in vacuo, and purified by flash column chromatography to afford 4,9-Dibromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carboxylic acid methyl ester (5.8 g, 94%) as a light yellow solid; LC-MS: 422.3 (M+3). 1H NMR (400 MHz, DMSO-d6): δ 8.40 (d, J=2.4 Hz, 1H), 7.53 (dd, J1=8.6 Hz, J2=2.44 Hz, 1H), 7.10 (d, J=8.64 Hz, 1H), 6.34 (d, J=1.8 Hz, 1H), 4.57 (m, 2H), 3.93 (s, 3H)

Workup

  1. temperatureThe mixture was heated
  2. temperatureto reflux overnight
  3. customThen the mixture was partitioned between EtOAc and H2O
  4. extractionThe aqueous layer was extracted with EtOAc (2×100 mL)
  5. washThe combined organic layers were washed with brine
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. custompurified by flash column chromatography

Sources & evidence

ORD record
ord-ef038ffbc2b3454583f1d62a1cbd1a39
Source dataset
uspto-grants-2015_05
Patent number
US09034866B2

Reaction notes

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