methyl 5,5-dimethyl-2,4-dioxohexanoate

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 57.2 g (1.06 mols) of sodium methylate are suspended in 400 g of dehydrated pinacolin. 118 g of molten oxalic acid dimethyl ester are added dropwise to the suspension in the course of 1 hour. The temperature is kept at 10° C. during this addition. The mixture is subsequently stirred for 15 minutes and 84 g of a methanol/pinacolin mixture are then distilled off at 64° C. The bottom product is cooled to 50° C. and 252 g of aqueous sulphuric acid (20.9% strength by weight) are added. Separation of the phases and subsequent distillation of the organic phase gives 164.6 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield), purity: 99.3%. The temperature is kept at 10° C. during this addition 84 g of a methanol/pinacolin mixture are then distilled off at 64° C 252 g of aqueous sulphuric acid (20.9% strength by weight) are added Separation of the phases and subsequent distillation of the organic phase

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 198 g of methanolic sodium methyate solution (30% strength by weight) are added to 400 g of chlorobenzene. The methanol is distilled off at 65° C. in the course of 1 hour. The mixture is cooled to 10° C. and 118 g (1 mol) of molten oxalic acid dimethyl ester are introduced in the course of 1 hour. Thereafter, 100 g (1 mol) of pinacolin are allowed to run in and the mixture is subsequently stirred at room temperature for 15 minutes. It is heated, and the methanol formed in the reaction is distilled off in the course of 2 hours. Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase gives 165 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield). Purity: 99.0%. The methanol is distilled off at 65° C. in the course of 1 hour It is heated is distilled off in the course of 2 hours Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 198 g of methanolic sodium methyate solution (30% strength by weight) are added to 400 g of chlorobenzene. The methanol is distilled off at 65° C. in the course of 1 hour. The mixture is cooled to 10° C. and 118 g (1 mol) of molten oxalic acid dimethyl ester are introduced in the course of 1 hour. Thereafter, 100 g (1 mol) of pinacolin are allowed to run in and the mixture is subsequently stirred at room temperature for 15 minutes. It is heated, and the methanol formed in the reaction is distilled off in the course of 2 hours. Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase gives 165 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield). Purity: 99.0%. The methanol is distilled off at 65° C. in the course of 1 hour It is heated is distilled off in the course of 2 hours Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase

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

Procedure: When a mixture, heated to 50° C., of pinacolin and oxalic acid dimethyl ester was added and the procedure was otherwise the same as in Example 6, a amount of 166.7 g of pivaloylpyruvic acid methyl ester (89% of the theoretical yield) were obtained. Purity: 99.3%. was added

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 118 g of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise to a suspension of 59.4 g (1.1 mols) of sodium methylate in 200 g of toluene, cooled to 5° C., in the course of 1 hour, whilst stirring. 100 g (1 mol) of technical grade pinacolin are allowed to run rapidly into the mixture. The mixture is subsequently stirred for 15 minutes and 90 g of a methanol/toluene mixture are then distilled off, at boiling point760 : 67° to 100° C., over a packed column in the course of 3 hours. The bottom product is cooled to 40° C. and 258 g of 20.9% strength by weight aqeuous sulphuric acid are added. Phase separation is effected after thorough stirring for 1 hour. Distillation of the organic phase at boiling point0.4 : 75° C. gives 163.5 g of pivaloylpyruvic acid methyl ester (87.0% of the theoretical yield) with a purity of 99.0% (by analysis by gas chromatography). The mixture is subsequently stirred for 15 minutes 90 g of a methanol/toluene mixture are then distilled off 67° to 100° C. in the course of 3 hours The bottom product is cooled to 40° C. 258 g of 20.9% strength by weight aqeuous sulphuric acid are added Phase separation after thorough stirring for 1 hour Distillation of the organic phase

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 118 g of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise to a suspension of 59.4 g (1.1 mols) of sodium methylate in 200 g of toluene, cooled to 5° C., in the course of 1 hour, whilst stirring. 100 g (1 mol) of technical grade pinacolin are allowed to run rapidly into the mixture. The mixture is subsequently stirred for 15 minutes and 90 g of a methanol/toluene mixture are then distilled off, at boiling point760 : 67° to 100° C., over a packed column in the course of 3 hours. The bottom product is cooled to 40° C. and 258 g of 20.9% strength by weight aqeuous sulphuric acid are added. Phase separation is effected after thorough stirring for 1 hour. Distillation of the organic phase at boiling point0.4 : 75° C. gives 163.5 g of pivaloylpyruvic acid methyl ester (87.0% of the theoretical yield) with a purity of 99.0% (by analysis by gas chromatography). The mixture is subsequently stirred for 15 minutes 90 g of a methanol/toluene mixture are then distilled off 67° to 100° C. in the course of 3 hours The bottom product is cooled to 40° C. 258 g of 20.9% strength by weight aqeuous sulphuric acid are added Phase separation after thorough stirring for 1 hour Distillation of the organic phase

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

Procedure: 54 g (1 mol) of sodium are suspended in 300 g of n-hexane. 118 g (1 mol) of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise at 0°-5° C. in the course of 1 hour. 100 g of pinacolin are then added rapidly at the same temperature. The mixture is stirred at room temperature for 15 minutes and 222 g of a n-hexane/methanol mixture are then distilled off, at boiling point760 : 50° C., over a 50 cm high packed column in the course of 6 hours. 234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product. Separation of the phases and subsequent distillation of the organic phase give, at boiling point8 : 105° C., 159 g of pivaloylpyruvic acid methyl ester (85.0% of the theoretical yield) with a purity of 99.4% (by analysis by gas chromatography). are added dropwise at 0°-5° C. in the course of 1 hour 222 g of a n-hexane/methanol mixture are then distilled off 50° C. in the course of 6 hours 234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product Separation of the phases and subsequent distillation of the organic phase give

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 57.2 g (1.06 mols) of sodium methylate are suspended in 400 g of dehydrated pinacolin. 118 g of molten oxalic acid dimethyl ester are added dropwise to the suspension in the course of 1 hour. The temperature is kept at 10° C. during this addition. The mixture is subsequently stirred for 15 minutes and 84 g of a methanol/pinacolin mixture are then distilled off at 64° C. The bottom product is cooled to 50° C. and 252 g of aqueous sulphuric acid (20.9% strength by weight) are added. Separation of the phases and subsequent distillation of the organic phase gives 164.6 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield), purity: 99.3%. The temperature is kept at 10° C. during this addition 84 g of a methanol/pinacolin mixture are then distilled off at 64° C 252 g of aqueous sulphuric acid (20.9% strength by weight) are added Separation of the phases and subsequent distillation of the organic phase

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 198 g of methanolic sodium methyate solution (30% strength by weight) are added to 400 g of chlorobenzene. The methanol is distilled off at 65° C. in the course of 1 hour. The mixture is cooled to 10° C. and 118 g (1 mol) of molten oxalic acid dimethyl ester are introduced in the course of 1 hour. Thereafter, 100 g (1 mol) of pinacolin are allowed to run in and the mixture is subsequently stirred at room temperature for 15 minutes. It is heated, and the methanol formed in the reaction is distilled off in the course of 2 hours. Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase gives 165 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield). Purity: 99.0%. The methanol is distilled off at 65° C. in the course of 1 hour It is heated is distilled off in the course of 2 hours Neutralisation with sulphuric acid, separation of the phases and distillation of the organic phase

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

Procedure: When a mixture, heated to 50° C., of pinacolin and oxalic acid dimethyl ester was added and the procedure was otherwise the same as in Example 6, a amount of 166.7 g of pivaloylpyruvic acid methyl ester (89% of the theoretical yield) were obtained. Purity: 99.3%. was added

Conditions: temp:5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 118 g of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise to a suspension of 59.4 g (1.1 mols) of sodium methylate in 200 g of toluene, cooled to 5° C., in the course of 1 hour, whilst stirring. 100 g (1 mol) of technical grade pinacolin are allowed to run rapidly into the mixture. The mixture is subsequently stirred for 15 minutes and 90 g of a methanol/toluene mixture are then distilled off, at boiling point760 : 67° to 100° C., over a packed column in the course of 3 hours. The bottom product is cooled to 40° C. and 258 g of 20.9% strength by weight aqeuous sulphuric acid are added. Phase separation is effected after thorough stirring for 1 hour. Distillation of the organic phase at boiling point0.4 : 75° C. gives 163.5 g of pivaloylpyruvic acid methyl ester (87.0% of the theoretical yield) with a purity of 99.0% (by analysis by gas chromatography). The mixture is subsequently stirred for 15 minutes 90 g of a methanol/toluene mixture are then distilled off 67° to 100° C. in the course of 3 hours The bottom product is cooled to 40° C. 258 g of 20.9% strength by weight aqeuous sulphuric acid are added Phase separation after thorough stirring for 1 hour Distillation of the organic phase

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

Procedure: 54 g (1 mol) of sodium are suspended in 300 g of n-hexane. 118 g (1 mol) of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise at 0°-5° C. in the course of 1 hour. 100 g of pinacolin are then added rapidly at the same temperature. The mixture is stirred at room temperature for 15 minutes and 222 g of a n-hexane/methanol mixture are then distilled off, at boiling point760 : 50° C., over a 50 cm high packed column in the course of 6 hours. 234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product. Separation of the phases and subsequent distillation of the organic phase give, at boiling point8 : 105° C., 159 g of pivaloylpyruvic acid methyl ester (85.0% of the theoretical yield) with a purity of 99.4% (by analysis by gas chromatography). are added dropwise at 0°-5° C. in the course of 1 hour 222 g of a n-hexane/methanol mixture are then distilled off 50° C. in the course of 6 hours 234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product Separation of the phases and subsequent distillation of the organic phase give