Diethyl Ether → 4-nitrobenzyl (5R)-6-[(acetyloxy)(5,6,7,8-tetrahydroimidazo[2,1-b][1,3]benzothiazol-2-yl)methyl]-6-bromo-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

HRID 638874Notes

Reaction equation

HRID 638874 reaction equation
[N:1]1[C:2]([CH:13]=[O:14])=[CH:3][N:4]2[C:8]3[CH2:9][CH2:10][CH2:11][CH2:12][C:7]=3[S:6][C:5]=12.[N+:15]([C:18]1[CH:36]=[CH:35][C:21]([CH2:22][O:23][C:24]([C:26]2[N:27]3[C@H:30]([S:31][CH:32]=2)[C@@H:29]([Br:33])[C:28]3=[O:34])=[O:25])=[CH:20][CH:19]=1)([O-:17])=[O:16].[Mg+2].[Br-].[Br-].[O:40](CC)[CH2:41][CH3:42].C(OC(=O)C)(=O)C>C(OCC)(=O)C.CCN(CC)CC.C(#N)C.C1COCC1>[C:41]([O:14][CH:13]([C:2]1[N:1]=[C:5]2[N:4]([CH:3]=1)[C:8]1[CH2:9][CH2:10][CH2:11][CH2:12][C:7]=1[S:6]2)[C:29]1([Br:33])[C:28](=[O:34])[N:27]2[C@@H:30]1[S:31][CH:32]=[C:26]2[C:24]([O:23][CH2:22][C:21]1[CH:35]=[CH:36][C:18]([N+:15]([O-:17])=[O:16])=[CH:19][CH:20]=1)=[O:25])(=[O:40])[CH3:42]

Participants

10

Reactant 5

HCID 3283Diethyl EtherHCID 7918Acetic AnhydrideHCID 82241Magnesium BromideHCID 11280588(5R,6S)-6-bromo-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitrobenzyl esterHCID 222244605,6,7,8-Tetrahydroimidazo[2,1-b][1,3]benzothiazole-2-carbaldehyde

Product 1

HCID 696085324-nitrobenzyl (5R)-6-[(acetyloxy)(5,6,7,8-tetrahydroimidazo[2,1-b][1,3]benzothiazol-2-yl)methyl]-6-bromo-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

Reagents, catalysts & solvents 4

HCID 6342AcetonitrileSolventHCID 8028TetrahydrofuranSolventHCID 8471TriethylamineSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
-20 °C

Procedure

5,6,7,8-tetrahydroimidazo[2,1-b][1,3]benzothiazole-2-carbaldehyde (412 mg, 2.0 mmol) and the dry THF solution (20 mL) of (5R,6S)-6-bromo-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester (770 mg, 2 mmol) were added successively to the dry acetonitrile (15 mL) solution of anhydrous MgBr2:O(Et)2 (1.2 g, 3.0 mmol) under an argon atmosphere at room temperature. After cooling to −20° C., Et3N (2.0 mL) was added in one portion. The reaction vessel was covered with foil to exclude light. The reaction mixture was stirred for 2 h at −20° C. and treated with acetic anhydride (1.04 mL) in one portion. The reaction mixture was warmed to 0° C. and stirred for 15 h at 0° C. The mixture was diluted with ethyl acetate and washed with 5% citric acid aqueous solution, saturated sodium hydrogen carbonate, and brine. The organic layer was dried (MgSO4) and filtered through a pad of Celite. The pad was washed with ethyl acetate. The filtrate was concentrated under reduced pressure. The residue was applied to silica gel column chromatography, then the column was eluted with ethyl acetate:hexane (1:1). Collected fractions were concentrated under reduced pressure and the mixture of diastereomers were taken to the next step. Pale yellow amorphous solid; Yield: 980 mg, 77%; M+H 634.

Workup

  1. customat room temperature
  2. temperatureThe reaction mixture was warmed to 0° C.
  3. stirringstirred for 15 h at 0° C
  4. washwashed with 5% citric acid aqueous solution, saturated sodium hydrogen carbonate, and brine
  5. dry with materialThe organic layer was dried (MgSO4)
  6. filtrationfiltered through a pad of Celite
  7. washThe pad was washed with ethyl acetate
  8. concentrationThe filtrate was concentrated under reduced pressure
  9. washthe column was eluted with ethyl acetate:hexane (1:1)
  10. concentrationCollected fractions were concentrated under reduced pressure
  11. additionthe mixture of diastereomers

Sources & evidence

ORD record
ord-8dfe3a1493124ec3b4e00880a42978aa
Source dataset
uspto-grants-2010_04
Patent number
US07691842B2

Reaction notes

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