Acetic Anhydride → 4-nitrobenzyl(5R)-6-[(acetyloxy)([1,3]thiazolo[3,2-a]benzimidazol-6-yl)methyl]-6-bromo-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

HRID 638900Notes

Reaction equation

HRID 638900 reaction equation
[S:1]1[CH:5]=[CH:4][N:3]2[C:6]3[CH:12]=[C:11]([CH:13]=[O:14])[CH:10]=[CH:9][C:7]=3[N:8]=[C:2]12.[Br-].[Mg+2].[Br-].[N+:18]([C:21]1[CH:39]=[CH:38][C:24]([CH2:25][O:26][C:27]([C:29]2[N:30]3[CH:33]([S:34][CH:35]=2)[CH:32]([Br:36])[C:31]3=[O:37])=[O:28])=[CH:23][CH:22]=1)([O-:20])=[O:19].[C:40](OC(=O)C)(=[O:42])[CH3:41]>C(OCC)(=O)C.C(N(CC)CC)C.C1COCC1.C(#N)C>[C:40]([O:14][CH:13]([C:11]1[CH:10]=[CH:9][C:7]2[N:8]=[C:2]3[S:1][CH:5]=[CH:4][N:3]3[C:6]=2[CH:12]=1)[C:32]1([Br:36])[C:31](=[O:37])[N:30]2[C@@H:33]1[S:34][CH:35]=[C:29]2[C:27]([O:26][CH2:25][C:24]1[CH:38]=[CH:39][C:21]([N+:18]([O-:20])=[O:19])=[CH:22][CH:23]=1)=[O:28])(=[O:42])[CH3:41]

Participants

9

Reactant 4

HCID 7918Acetic AnhydrideHCID 82241Magnesium BromideHCID 22224493Benzo[4,5]imidazo[2,1-b]thiazole-6-carbaldehydeHCID 684433356-Bromo-7-oxo-4-thia-1-aza-bicyclo[3.2.0]hept-2-ene-2-carboxylic acid 4-nitro-benzyl ester

Product 1

HCID 696085974-nitrobenzyl(5R)-6-[(acetyloxy)([1,3]thiazolo[3,2-a]benzimidazol-6-yl)methyl]-6-bromo-7-oxo-4-thia-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylateYield 50%

Reagents, catalysts & solvents 4

HCID 6342AcetonitrileSolventHCID 8028TetrahydrofuranSolventHCID 8471TriethylamineSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
23 °C

Procedure

A 30 ml acetonitrile solution of benzo[4,5]imidazo[2,1-b]thiazole-6-carbaldehyde (404 mg, 2 mmol) was added 1.03 gram of magnesium bromide etherate. The mixture was stirred at 23° C. for half an hour. Then a 30 ml dry THF solution of the 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) was injected within a minute and the reaction mixture was then cooled to −20° C. Triethylamine (0.7 ml, eq.) was then injected and the reaction mixture was stirred for five hours at −20° C. Then acetic anhydride (0.377 ml, eq.) was injected and the reaction mixture was left at zero degree for 18 hours. The reaction media was then diluted with 400 ml ethyl acetate and washed with 100 ml 5% citric acid, 100 ml saturated sodium bicarbonate, and 100 ml brine. The organic layer was then dried over magnesium sulfate, filtered and concentrated. Flash column chromatography using 20% ethyl acetate in hexane gave 630 mg product. (50% Yield); MS: 631.9 (M+H)

Workup

  1. temperaturethe reaction mixture was then cooled to −20° C
  2. stirringthe reaction mixture was stirred for five hours at −20° C
  3. customThe reaction media
  4. washwashed with 100 ml 5% citric acid, 100 ml saturated sodium bicarbonate, and 100 ml brine
  5. dry with materialThe organic layer was then dried over magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-1b7a495c2419485aab007e23b6b86772
Source dataset
uspto-grants-2010_04
Patent number
US07691842B2

Reaction notes

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