Carbon tetrabromide → methyl 7-[bis-(tert-butoxycarbonyl)amino]-4H-furo[2,3-c]-chromene-6-carboxylate

HRID 1778338Notes

Reaction equation

HRID 1778338 reaction equation
C(Br)(Br)(Br)Br.[C:6]([O:10][C:11]([N:13]([C:32]([O:34][C:35]([CH3:38])([CH3:37])[CH3:36])=[O:33])[C:14]1[C:19]([C:20]([O:22][CH3:23])=[O:21])=[C:18]([OH:24])[C:17]([C:25]2[CH:29]=[CH:28][O:27][C:26]=2[CH2:30]O)=[CH:16][CH:15]=1)=[O:12])([CH3:9])([CH3:8])[CH3:7].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C(Cl)Cl>[C:6]([O:10][C:11]([N:13]([C:32]([O:34][C:35]([CH3:38])([CH3:36])[CH3:37])=[O:33])[C:14]1[C:19]([C:20]([O:22][CH3:23])=[O:21])=[C:18]2[C:17]([C:25]3[CH:29]=[CH:28][O:27][C:26]=3[CH2:30][O:24]2)=[CH:16][CH:15]=1)=[O:12])([CH3:9])([CH3:7])[CH3:8]

Participants

5

Reactant 3

HCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 66685556Methyl 6-[bis-(tert-butoxycarbonyl)amino]-2-hydroxy-3-(2-hydroxymethylfuran-3-yl)benzoate2×

Product 1

HCID 68093020methyl 7-[bis-(tert-butoxycarbonyl)amino]-4H-furo[2,3-c]-chromene-6-carboxylateYield 28.9%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Carbon tetrabromide (2.66 g) was added to a solution of methyl 6-[bis-(tert-butoxycarbonyl)amino]-2-hydroxy-3-(2-hydroxymethylfuran-3-yl)-benzoate (Intermediate 17, 2.65 g) and triphenyl phosphine (2.1 g) in DCM (40 mL) and the resultant solution was stirred at room temperature for 1 hour. The mixture was evaporated to dryness and DMF (60 mL) and cesium carbonate (5.59 g) were added to the residue. The resultant mixture was stirred for 1 hour, then partitioned between ethyl acetate and water. The organic layer was separated, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 5-25% to give methyl 7-[bis-(tert-butoxycarbonyl)amino]-4H-furo[2,3-c]-chromene-6-carboxylate (0.735 g) as a gum which crystallised on standing.

Workup

  1. customThe mixture was evaporated to dryness and DMF (60 mL) and cesium carbonate (5.59 g)
  2. additionwere added to the residue
  3. custompartitioned between ethyl acetate and water
  4. customThe organic layer was separated
  5. dry with materialdried (Na2SO4)
  6. filtrationfiltered
  7. customThe filtrate was evaporated to dryness
  8. customthe residue was purified by chromatography on silica
  9. washeluting with a mixture of ethyl acetate and cyclohexane with a gradient of 5-25%

Sources & evidence

ORD record
ord-83ff22257c9841b9a6ab66abf03335dc
Source dataset
uspto-grants-2016_02
Patent number
US09266896B2

Reaction notes

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