Methanesulfonic Acid → 8-bromo-3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-one

HRID 2091595Notes

Reaction equation

HRID 2091595 reaction equation
[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6](=[O:12])[CH2:7][CH2:8][O:9]2)=[CH:4][CH:3]=1.CS(O)(=O)=O.[N-:18]=[N+]=[N-].[Na+].[OH-].[Na+]>C(Cl)Cl.O>[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[C:6](=[O:12])[NH:18][CH2:7][CH2:8][O:9][C:10]=2[CH:11]=1

Participants

7

Reactant 4

HCID 6395Methanesulfonic AcidHCID 14798Sodium HydroxideHCID 33557Sodium AzideHCID 223357367-bromo-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 706551658-bromo-3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-oneYield 101.9%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent2×

Conditions

Temperature
0 °C

Procedure

A solution of 7-bromochroman-4-one (340 mg, 1.5 mmol) and methanesulfonic acid (3 mL, 23.0 mmol) in DCM was cooled to 0° C. and treated with NaN3 (146 mg, 2.25 mmol) portionwise, while maintaining the internal temperature below 5° C. The reaction was then stirred at 0° C. for 4 h. At completion, the reaction was slowly neutralized with 8 N aq. NaOH, then diluted with DCM (20 mL) and water (20 mL). The layers were separated and the organics were dried over MgSO4, filtered and evaporated to afford 8-bromo-3,4-dihydrobenzo[f][1,4]oxazepin-5(2H)-one (370 mg, 100% yield). MS (EI) m/z=242.1 [M+1]+.

Workup

  1. temperaturewhile maintaining the internal temperature below 5° C
  2. customThe layers were separated
  3. dry with materialthe organics were dried over MgSO4
  4. filtrationfiltered
  5. customevaporated

Sources & evidence

ORD record
ord-00920c737cf641ca9f476fbbc8681774
Source dataset
uspto-grants-2013_05
Patent number
US08440652B2

Reaction notes

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