3,4-Diisopropoxy-3-cyclobutene-1,2-dione → HCID 19955586, compound

HRID 1779438Notes

Reaction equation

HRID 1779438 reaction equation
Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=1.C([Li])CCC.[CH:20]([O:23][C:24]1[C:25](=O)[C:26](=[O:32])[C:27]=1[O:28]C(C)C)([CH3:22])[CH3:21]>O1CCCC1>[CH:20]([O:23][C:24]1[C:27](=[O:28])[C:26](=[O:32])[C:25]=1[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=1)([CH3:22])[CH3:21]

Participants

5

Reactant 3

HCID 1823143,4-Diisopropoxy-3-cyclobutene-1,2-dioneHCID 10105993HCID 10105993, compoundHCID 178418339Butyllithium

Product 1

HCID 19955586HCID 19955586, compoundYield 60.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-70 °C

Procedure

To a solution of 2-bromo-4'-methylbiphenyl (9.0 g; obtainable as described in Example 3 (a) and in Gomberg and Pernert, J. Am. Chem. Soc. (1926) Vol 48 p 1373) in tetrahydrofuran (60 ml) was added butyllithium (2.5M in hexanes, 15.3 ml) dropwise at -70° C. under a nitrogen atmosphere over a period of 3 minutes. The mixture was stirred for 10 minutes at -70° C. then added to a solution of 3,4-diisopropoxycyclobut-3-ene-1,2-dione (7.6 g) in tetrahydrofuran (100 ml) at -70° C. under nitrogen over a period of 1 minute. The solution obtained was stirred for an additional 30 minutes at -70° C. then quenched with trifluoroacetic anhydride (6.4 ml), followed by saturated aqueous ammonium chloride (40 ml). The resulting mixture was allowed to warm to ambient temperature, then partitioned between diethyl ether (300 ml) and aqueous sodium bicarbonate (5%, 300 ml). The aqueous layer was re-extracted with diethyl ether (200 ml) and the combined organic layers were washed with brine, dried over magnesium sulphate, and evaporated to give a yellow oily solid which was purified by flash chromatography on silica gel (eluting with 10% rising to 20% ethyl acetate in petroleum ether (b.p. 60°-80° C.)) to give the intermediate compound 3-isopropoxy-4-(4'-methylbiphenyl-2-yl)cyclobut-3-ene-1,2-dione as a yellow solid (6.7 g), substantially identical to the product of Example 1(b). The above method is described in Reed et al, Journal of Organic Chemistry (1988) Vol.53, p 2477.

Workup

  1. customdropwise at -70° C.
  2. customof 3 minutes
  3. customThe solution obtained
  4. stirringwas stirred for an additional 30 minutes at -70° C.
  5. customthen quenched with trifluoroacetic anhydride (6.4 ml)
  6. temperatureto warm to ambient temperature
  7. custompartitioned between diethyl ether (300 ml) and aqueous sodium bicarbonate (5%, 300 ml)
  8. extractionThe aqueous layer was re-extracted with diethyl ether (200 ml)
  9. washthe combined organic layers were washed with brine
  10. dry with materialdried over magnesium sulphate
  11. customevaporated
  12. customto give a yellow oily solid which
  13. customwas purified by flash chromatography on silica gel (eluting with 10% rising to 20% ethyl acetate in petroleum ether (b.p. 60°-80° C.))

Sources & evidence

ORD record
ord-8e7e3660dae64aeeae69216a49751cdd
Source dataset
uspto-grants-1997_05
Patent number
US05627191

Reaction notes

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