二氢-4,4-二甲基-2,3-呋喃二酮

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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).

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Dihydro-4,4-dimethyl-2,3-furandione (2 g, 15.6 mmole) and 1,3-diaminoguanidine monohydrochloride (12.96 g, 15.61 immole) were dissolved in ethanol and the resulting solution heated to reflux temperatures. To the refluxing reaction mixture, was added water until a clear solution was obtained. The mixture was then refluxed overnight, cooled to room temperature and stored at -20° C. overnight. The product which separated was filtered and dried. It was crystallized from a mixture of ethanol and water to give 3,4-diamino-6-(1',1'-dimethyl-2'-hydroxyethyl)-1,2,4,-triazin-5(4H)-one hydrochloride (2.24 g, 61%), m.p. 221-222° C. (dec). the resulting solution heated to reflux temperatures To the refluxing reaction mixture was obtained The mixture was then refluxed overnight The product which separated was filtered dried It was crystallized from a mixture of ethanol and water

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Dihydro-4,4-dimethyl-2,3-furandione (2 g, 15.6 mmole) and 1,3-diaminoguanidine monohydrochloride (12.96 g, 15.61 immole) were dissolved in ethanol and the resulting solution heated to reflux temperatures. To the refluxing reaction mixture, was added water until a clear solution was obtained. The mixture was then refluxed overnight, cooled to room temperature and stored at -20° C. overnight. The product which separated was filtered and dried. It was crystallized from a mixture of ethanol and water to give 3,4-diamino-6-(1',1'-dimethyl-2'-hydroxyethyl)-1,2,4,-triazin-5(4H)-one hydrochloride (2.24 g, 61%), m.p. 221-222° C. (dec). the resulting solution heated to reflux temperatures To the refluxing reaction mixture was obtained The mixture was then refluxed overnight The product which separated was filtered dried It was crystallized from a mixture of ethanol and water

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Burkholderia caryophylli Lu681 (or other strains from Tab. 1) were grown in 25 ml of complex medium (for example HFP=1% peptone, 1% tryptone, 0.5% yeast extract, 0.3% NaCL) for 1 to 3 days, harvested, washed in Tris-HCl buffer (50 mM, pH 7.0) and resuspended (5 ml of 50 mM Tris/HCl, pH 7.0) and incubated with 50 mM ketopantolactone at 30° C. for 3 h. After removal of the cells, the concentrations of ketopantolactone, ketopantoic acid, D,L-pantolactone, D,L-, D-, and L-pantoic acid were determined by HPLC analysis (Tab. 1a). All the listed strains apart from Beauveria amorpha Lu7953 were able to reduce to pantoic acid the ketopantoic acid resulting from spontaneous hydrolysis of ketopantolactone. Since, however, D-pantoic acid was formed with all the strains instead of the L-pantoic acid described in Example 1, the conversion of pantolactone to L-pantoic acid cannot be produced by an oxidation-reduction process (via ketopantolactone and ketopantoic acid). No dependence of the L-pantolactone hydrolysis on cofactors was found in the dialyzed crude extract from Lu681 or Lu5351 and on use of the purified enzymes from Lu681 and Lu5351 either. The enzymatic activity can thus be attributed to a hydrolytic enzyme.

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Burkholderia caryophylli Lu681 (or other strains from Tab. 1) were grown in 25 ml of complex medium (for example HFP=1% peptone, 1% tryptone, 0.5% yeast extract, 0.3% NaCL) for 1 to 3 days, harvested, washed in Tris-HCl buffer (50 mM, pH 7.0) and resuspended (5 ml of 50 mM Tris/HCl, pH 7.0) and incubated with 50 mM ketopantolactone at 30° C. for 3 h. After removal of the cells, the concentrations of ketopantolactone, ketopantoic acid, D,L-pantolactone, D,L-, D-, and L-pantoic acid were determined by HPLC analysis (Tab. 1a). All the listed strains apart from Beauveria amorpha Lu7953 were able to reduce to pantoic acid the ketopantoic acid resulting from spontaneous hydrolysis of ketopantolactone. Since, however, D-pantoic acid was formed with all the strains instead of the L-pantoic acid described in Example 1, the conversion of pantolactone to L-pantoic acid cannot be produced by an oxidation-reduction process (via ketopantolactone and ketopantoic acid). No dependence of the L-pantolactone hydrolysis on cofactors was found in the dialyzed crude extract from Lu681 or Lu5351 and on use of the purified enzymes from Lu681 and Lu5351 either. The enzymatic activity can thus be attributed to a hydrolytic enzyme.