N-bromobutanimide → (3R,4S)-4-{(2S)-2-benzyloxycarbonylaminopropionyloxy}-3-bromo-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile

HRID 704775

Reaction equation

HRID 704775 reaction equation
[Br:1]N1C(=O)CCC1=O.[CH3:9][C:10]1([CH3:22])[CH:15]=[CH:14][C:13]2[CH:16]=[C:17]([C:20]#[N:21])[CH:18]=[CH:19][C:12]=2[O:11]1.[CH2:23]([O:30][C:31]([NH:33][C@H:34]([C:36]([OH:38])=[O:37])[CH3:35])=[O:32])[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1.C(=O)(O)[O-].[Na+]>C(Cl)(Cl)Cl>[CH2:23]([O:30][C:31]([NH:33][C@@H:34]([CH3:35])[C:36]([O:38][C@H:14]1[C:13]2[CH:16]=[C:17]([C:20]#[N:21])[CH:18]=[CH:19][C:12]=2[O:11][C:10]([CH3:22])([CH3:9])[C@@H:15]1[Br:1])=[O:37])=[O:32])[C:24]1[CH:25]=[CH:26][CH:27]=[CH:28][CH:29]=1

Participants

6

Reactant 4

HCID 67184N-bromobutanimideHCID 516892Sodium BicarbonateHCID 736104N-carbobenzyloxyalanineHCID 27790742,2-dimethyl-2H-1-benzopyran-6-carbonitrile

Product 1

HCID 18643511(3R,4S)-4-{(2S)-2-benzyloxycarbonylaminopropionyloxy}-3-bromo-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-6-carbonitrileYield 29.2%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

N-Bromosuccinimide (6.408 g) was added to a solution of 2,2-dimethyl-2H-1-benzopyran-6-carbonitrile (5.55 g) and N-benzyloxycarbonyl-L-alanine (6.69 g) in chloroform (60 ml). After being stirred under reflux for 16 hours, the mixture was poured into saturated aqueous sodium bicarbonate and diluted with chloroform. The organic layer was separated, washed successively with 5% aqueous sodium thiosulfate, water, and brine, dried over magnesium sulfate, and evaporated in vacuo. The oily residue was dissolved in diisopropyl ether and allowed to stand at ambient temperature. The resulting precipitates were collected by filtration, washed with diisopropyl ether, and dried to give (3R,4S)-4-{(2S)-2-benzyloxycarbonylaminopropionyloxy}-3-bromo-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile (4.26 g).

Workup

  1. temperatureunder reflux for 16 hours
  2. customThe organic layer was separated
  3. washwashed successively with 5% aqueous sodium thiosulfate, water, and brine
  4. dry with materialdried over magnesium sulfate
  5. customevaporated in vacuo
  6. dissolutionThe oily residue was dissolved in diisopropyl ether
  7. customto stand at ambient temperature
  8. customThe resulting precipitates
  9. filtrationwere collected by filtration
  10. washwashed with diisopropyl ether
  11. customdried

Sources & evidence

ORD record
ord-cb274ed93a204a2890355bd1365967bf
Source dataset
uspto-grants-1991_01
Patent number
US04988723

Linked notes

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