Trifluoroacetic acid → (3S-trans)-3-Benzyloxycarbonylamino-4-methylazetidinone

HRID 1761634Notes

Reaction equation

HRID 1761634 reaction equation
[C:1]([O:5][C:6]([NH:8][C@H:9]1[C@H:12]([CH3:13])[NH:11][C:10]1=[O:14])=[O:7])([CH3:4])(C)C.FC(F)(F)C(O)=O.[C:22]1(OC)[CH:27]=[CH:26]C=[CH:24][CH:23]=1>ClCCl>[CH2:1]([O:5][C:6]([NH:8][C@H:9]1[C@H:12]([CH3:13])[NH:11][C:10]1=[O:14])=[O:7])[C:4]1[CH:26]=[CH:27][CH:22]=[CH:23][CH:24]=1

Participants

5

Reactant 3

HCID 6422Trifluoroacetic acidHCID 7519AnisoleHCID 13155285tert-Butyl ((2S,3S)-2-methyl-4-oxoazetidin-3-yl)carbamate

Product 1

HCID 13182463(3S-trans)-3-Benzyloxycarbonylamino-4-methylazetidinone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of 3.3 g of (3S-trans)-3-t-butoxycarbonylamino-4-methylazetidinone in 10 ml each of dichloromethane and anisole was cooled to 0° C. and 112 ml of trifluoroacetic acid was added. The solution was stirred for 90 minutes and evaporated in vacuo (benzene added and evaporated three times). The residue was dissolved in 70 ml of acetone and the solution was adjusted to pH 7 with 5% sodium bicarbonate solution. A total of 5.33 g of benzyl chloroformate was added over 1 hour at pH 6.5-7.5. The mixture was stirred for 30 minutes at pH 7, diluted with 100 ml of saturated salt, and extracted with ethyl acetate (three 400 ml portions). The residue obtained by evaporation was chromatographed on a 1 liter silica gel column. Elution with chloroform-ethyl acetate (4:1) gave 2.19 g of compound. Crystallization from ether-hexane yielded 1.125 g of the title compound.

Workup

  1. customevaporated in vacuo (benzene added and evaporated three times)
  2. dissolutionThe residue was dissolved in 70 ml of acetone
  3. additionA total of 5.33 g of benzyl chloroformate was added over 1 hour at pH 6.5-7.5
  4. stirringThe mixture was stirred for 30 minutes at pH 7
  5. additiondiluted with 100 ml of saturated salt
  6. extractionextracted with ethyl acetate (three 400 ml portions)
  7. customThe residue obtained by evaporation
  8. customwas chromatographed on a 1 liter silica gel column
  9. washElution with chloroform-ethyl acetate (4:1)

Sources & evidence

ORD record
ord-adf7a306875740949acbaa7c3412e322
Source dataset
uspto-grants-1989_05
Patent number
US04826973

Reaction notes

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