3-hydroxy-4,4-dimethyloxolan-2-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:70.01; pressure:0.00; stir:

Procedure: Dilution of the aliquot (2 uL) with DMSO (200 uL).

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.18 g (9.1 mmol) of pantolactone were dissolved in 27 ml of methylene chloride at 22° C. in a 50 ml reaction flask. 777 mg (9.5 mmol) of sodium acetate and 850 mg (3.7 mmol) of trichloroisocyanuric acid were added thereto. The mixture was cooled to 0° C. while stirring. 18.5% of ketopantolactone were obtained after a reaction period of 6 hours at 0° C. After a further reaction period of 20 hours at 22° C. the composition was 22.2% of ketopantolactone and 77.5% of pantolactone (area percent).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2.5 g (19.2 mmol) of pantolactone were reacted with 1.8 g (7.7 mmol) of trichloroisocyanuric acid in the presence of 30 mg (0.12 mmol) of TEMPO derivative C and 1.65g (20.1 mmol) of sodium acetate analogously to Example 14. In contrast to Example 14, ethyl acetate (20 ml) was used as the solvent. The reaction had finished after 2 hours. After recrystallization of the crude product there were obtained 2.2 g (89%) of ketopantolactone, m.p. 68°-69° C., GC content: 100% (area percent). After recrystallization of the crude product

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5 g (38.4 mmol) of pantolactone were reacted with 3.6 g (15.5 mmol) of trichloroisocyanuric acid as described in Example 13. In contrast to Example 13, 63 mg (0.24 mmol) of Tempo derivative D were used as the catalyst. The reaction had finished after 1 hour. After recrystallization of the crude product there were obtained 4.85 g (98%) of ketopantolactone, m.p. 68°-69° C., GC content: 100% (area percent). After recrystallization of the crude product

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5 g (38.4 mmol) of pantolactone were reacted with 3.6 g (15.5 mmol) of trichloroisocyanuric acid as described in Example 13. In contrast to Example 13, 60 mg (0.25 mmol) of TEMPO derivative C were used as the catalyst. The reaction had finished after 3 hours. After recrystallization of the crude product there were obtained 4.6 g (93%) of ketopantolactone, m.p. 69°-70° C., GC content: 100% (area percent). After recrystallization of the crude product

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5 g (38.4 mmol) of 2-hydroxy-3,3-dimethyl-γ-butyrolactone (pantolactone) were dissolved in 118 ml of methylene chloride in a 200 ml sulphonation flask. 3.3 g (40.2 mmol) of sodium acetate and 3.6 g (15.5 mmol) of trichloroisocyanuric acid were added thereto. The mixture was cooled to 0° C. while stirring. A solution of 60 mg (0.28 mmol) of TEMPO derative B in 2 ml of methylene chloride was dosed in within 10 minutes. The temperature was held at 0°-3° C. by constant cooling. The reaction had finished after 3 hours. The white precipitate was filtered off and the filtrate was treated with sodium bisulphite solution in order to reduce the excess trichloroisocyanuric acid. Working up of the reaction mixture and subsequent recrystallization of the crude product gave 3.5 g (71%) of ketopantolactone, GC content: 99.6% (area percent). was dosed in within 10 minutes was held at 0°-3° C. by constant cooling The white precipitate was filtered off the filtrate was treated with sodium bisulphite solution in order Working up of the reaction mixture and subsequent recrystallization of the crude product

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5 g (38.4 mmol) of 2-hydroxy-3,3-dimethyl-γ-butyrolactone (pantolactone) were dissolved in 118 ml of methylene chloride in a 200 ml sulphonation flask. 3.3 g (40.2 mmol) of sodium acetate and 3.6 g (15.5 mmol) of trichloroisocyanuric acid were added thereto. The mixture was cooled to 0° C. while stirring. A solution of 38.2 mg (0.24 mmol) of TEMPO in 2 ml of methylene chloride was dosed in within 10 minutes. The temperature was held at 0°-3° C. by constant cooling. After a reaction period of 7 hours the white precipitate was filtered off. The filtrate was concentrated. Chromatography of the residue (SiO2, toluene/ethyl acetate 85:15) and subsequent recrystallization of the chromatographed product gave 4.23g (86%) of ketopantolactone, m.p. 67.5°-68° C., GC content: 100% (area percent). was dosed in within 10 minutes was held at 0°-3° C. by constant cooling After a reaction period of 7 hours the white precipitate was filtered off The filtrate was concentrated Chromatography of the residue (SiO2, toluene/ethyl acetate 85:15) and subsequent recrystallization of the chromatographed product

Conditions: temp:0.00; pressure:0.00; stir: