Sulfuric Acid → Diacetone L-sorbose

HRID 2289172Notes

Reaction equation

HRID 2289172 reaction equation
S(=O)(=O)(O)O.[OH:6][CH2:7][C:8]([C@H:10]([C@@H:12]([C@H:14]([CH2:16][OH:17])[OH:15])[OH:13])[OH:11])=[O:9].C([O-])(O)=O.[Na+]>CC(C)=O>[CH3:7][C:8]1([CH3:10])[O:11][C@H:10]2[C@@H:12]3[O:13][C:14]([CH3:16])([CH3:12])[O:15][C@:14]3([CH2:16][OH:17])[O:9][C@H:8]2[CH2:7][O:6]1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 6904L-(-)-SorboseHCID 516892Sodium Bicarbonate

Product 1

HCID 11043496Diacetone L-sorboseYield 132.9%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Conditions

Temperature
2.5 °C

Procedure

24 mL of sulfuric acid were added dropwise, with vigorous stirring, to 100 mL of acetone cooled to 0-5° C., at a rate such that the reaction temperature remained below 20° C. 5 g of L-sorbose were added to the reaction mixture, and stirring was allowed to continue for 4 h at room temperature. The reaction mixture was allowed to stand at room temperature overnight, and was cooled to -8° C. (ice-NaCl bath). The cooled reaction mixture was neutralized to pH 8 with saturated NaHCO3 at a rate such that the reaction temperature remained below 0° C. The resulting mixture containing precipitated Na2SO4 was allowed to warm to room temperature and the Na2SO4 was filtered and washed twice with dry acetone. Combined organic filtrate and washings were concentrated in vacuo at 20° C., and the resulting oily residue was extracted with chloroform (5×10 mL). The chloroform extract was dried (MgSO4) and evaporated to afford a viscous gum which crystallized (mp.=59-61° C.) upon standing. Recrystallization (benzene) of the above crystallized gum afforded 4.8 g (67%) of the above-titled compound as fine crystals: mp.=76-77° C. (lit. 77-78° C. (T. Reichstein et al., Helv. Chim. Acta, 1934, 17, 331); 1H NMR (CDCl3) δ1.35 (s, 6H), 1.45 (s, 3H), 1.52 (s, 3H), 2.50 (br. s, 1H, OH), 3.75-3.90 (m, 2H, 6-H2), 4.05-4.15 (m, 3H), 4.33 (d, 1H, 3H), 4.5 (d, 1H, J≈1H, 1-H).

Workup

  1. customremained below 20° C
  2. waitto stand at room temperature overnight
  3. customThe cooled reaction mixture
  4. customremained below 0° C
  5. additionThe resulting mixture containing
  6. customprecipitated Na2SO4
  7. temperatureto warm to room temperature
  8. filtrationthe Na2SO4 was filtered
  9. washwashed twice with dry acetone
  10. concentrationCombined organic filtrate and washings were concentrated in vacuo at 20° C.
  11. extractionthe resulting oily residue was extracted with chloroform (5×10 mL)
  12. extractionThe chloroform extract
  13. dry with materialwas dried (MgSO4)
  14. customevaporated
  15. customto afford a viscous gum which
  16. customcrystallized (mp.=59-61° C.)
  17. customRecrystallization (benzene) of the
  18. customabove crystallized gum

Sources & evidence

ORD record
ord-40df3539424a4050ade310c29671ebd6
Source dataset
uspto-grants-2000_07
Patent number
US06090950

Reaction notes

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