2,2-dimethylpentan-3-one

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

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

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

Procedure: A solution of 40 g of hydrogen chloride in 156 g of diethyl ether is added dropwise at room temperature to 96 g (0.84 mol) of 2,2-dimethyl-3-pentanone in 960 g of toluene. After cooling to -10° C., a solution of 95 g of n-butyl nitrite in 470 g of diethyl ether is added dropwise. The mixture is stirred at from -10° C. to 0° C. for 4 hours and then allowed to come to room temperature. After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time and then extracted twice with 1 l of 1M sodium hydroxide solution each time. The alkaline phase is separated off and neutralized with 20% strength sulfuric acid. The crude product is filtered off with suction and, after drying, recrystallized from n-hexane. 66 g (55%) of the title compound are obtained as a pale yellow powder of melting point 107-110° C. to come to room temperature After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time extracted twice with 1 l of 1M sodium hydroxide solution each time The alkaline phase is separated off The crude product is filtered off with suction after drying recrystallized from n-hexane

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

Procedure: A solution of 40 g of hydrogen chloride in 156 g of diethyl ether is added dropwise at room temperature to 96 g (0.84 mol) of 2,2-dimethyl-3-pentanone in 960 g of toluene. After cooling to -10° C., a solution of 95 g of n-butyl nitrite in 470 g of diethyl ether is added dropwise. The mixture is stirred at from -10° C. to 0° C. for 4 hours and then allowed to come to room temperature. After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time and then extracted twice with 1 l of 1M sodium hydroxide solution each time. The alkaline phase is separated off and neutralized with 20% strength sulfuric acid. The crude product is filtered off with suction and, after drying, recrystallized from n-hexane. 66 g (55%) of the title compound are obtained as a pale yellow powder of melting point 107°-110° C. to come to room temperature After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time extracted twice with 1 l of 1M sodium hydroxide solution each time The alkaline phase is separated off The crude product is filtered off with suction after drying recrystallized from n-hexane

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

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

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

Procedure: 0.86 g (4.1 mmol) of -methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid hydrazide and 1.14 g (10 mmol) of 2,2 dimethyl pentan-3-one, 30 mL of ethyl alcohol and 20 drops of glacial acetic acid were refluxed for 6 hours. TLC indicated ca. a 60% conversion to 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid (1-ethyl-2,2-dimethyl-propylidene)-hydrazide (Rf=0.40, 1:1 ethyl acetate:hexane). The reaction was cooled, 3 mL of glacial acetic acid followed by 0.63 g (10 mmol) of sodium cyanoborohydride were added, and the reaction was stirred at room temperature for 3 hours. Most of the alcohol was removed on a rotary evaporator. 30 mL of water was added, followed by the addition of 10% NaOH/H2O until the reaction mixture was basic. The mixture was extracted extensively with ethyl acetate. The ethyl acetate extract was dried and evaporated to give 1.2 g of crude material. The product was purified by column chromatography on silica gel, eluting with 20-30% ethyl acetate/hexane. About 0.46 g of pure 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid N′-(1-ethyl-2,2-dimethyl-propyl)-hydrazide was obtained. TLC: Rf=0.46 (1:1 ethyl acetate:hexane). 1H NMR (CDCl3, 500 MHz) δ (ppm): 7.1 (br, 1H[NH]), 6.85 (d, 1H), 6.71 (d, 1H), 4.8 (br, 1H), 4.29 (m, 2H), 4.25 (m, 2H), 2.4 (m, 1H), 2.29 (s, 3H), 1.7 (m, 1H), 1.3 (m, 1H), 1.15 (t, 3H), 0.98 (s, 9H). The reaction was cooled were added Most of the alcohol was removed on a rotary evaporator 30 mL of water was added followed by the addition of 10% NaOH/H2O until the reaction mixture The mixture was extracted extensively with ethyl acetate The ethyl acetate extract was dried evaporated to give 1.2 g of crude material The product was purified by column chromatography on silica gel eluting with 20-30% ethyl acetate/hexane

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

Procedure: 0.86 g (4.1 mmol) of -methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid hydrazide and 1.14 g (10 mmol) of 2,2 dimethyl pentan-3-one, 30 mL of ethyl alcohol and 20 drops of glacial acetic acid were refluxed for 6 hours. TLC indicated ca. a 60% conversion to 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid (1-ethyl-2,2-dimethyl-propylidene)-hydrazide (Rf=0.40, 1:1 ethyl acetate:hexane). The reaction was cooled, 3 mL of glacial acetic acid followed by 0.63 g (10 mmol) of sodium cyanoborohydride were added, and the reaction was stirred at room temperature for 3 hours. Most of the alcohol was removed on a rotary evaporator. 30 mL of water was added, followed by the addition of 10% NaOH/H2O until the reaction mixture was basic. The mixture was extracted extensively with ethyl acetate. The ethyl acetate extract was dried and evaporated to give 1.2 g of crude material. The product was purified by column chromatography on silica gel, eluting with 20-30% ethyl acetate/hexane. About 0.46 g of pure 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid N′-(1-ethyl-2,2-dimethyl-propyl)-hydrazide was obtained. TLC: Rf=0.46 (1:1 ethyl acetate:hexane). 1H NMR (CDCl3, 500 MHz) δ (ppm): 7.1 (br, 1H[NH]), 6.85 (d, 1H), 6.71 (d, 1H), 4.8 (br, 1H), 4.29 (m, 2H), 4.25 (m, 2H), 2.4 (m, 1H), 2.29 (s, 3H), 1.7 (m, 1H), 1.3 (m, 1H), 1.15 (t, 3H), 0.98 (s, 9H). The reaction was cooled were added Most of the alcohol was removed on a rotary evaporator 30 mL of water was added followed by the addition of 10% NaOH/H2O until the reaction mixture The mixture was extracted extensively with ethyl acetate The ethyl acetate extract was dried evaporated to give 1.2 g of crude material The product was purified by column chromatography on silica gel eluting with 20-30% ethyl acetate/hexane

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

Procedure: A solution of 40 g of hydrogen chloride in 156 g of diethyl ether is added dropwise at room temperature to 96 g (0.84 mol) of 2,2-dimethyl-3-pentanone in 960 g of toluene. After cooling to -10° C., a solution of 95 g of n-butyl nitrite in 470 g of diethyl ether is added dropwise. The mixture is stirred at from -10° C. to 0° C. for 4 hours and then allowed to come to room temperature. After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time and then extracted twice with 1 l of 1M sodium hydroxide solution each time. The alkaline phase is separated off and neutralized with 20% strength sulfuric acid. The crude product is filtered off with suction and, after drying, recrystallized from n-hexane. 66 g (55%) of the title compound are obtained as a pale yellow powder of melting point 107°-110° C. to come to room temperature After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time extracted twice with 1 l of 1M sodium hydroxide solution each time The alkaline phase is separated off The crude product is filtered off with suction after drying recrystallized from n-hexane

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

Procedure: A solution of 40 g of hydrogen chloride in 156 g of diethyl ether is added dropwise at room temperature to 96 g (0.84 mol) of 2,2-dimethyl-3-pentanone in 960 g of toluene. After cooling to −10° C., a solution of 95g of n-butyl nitrite in 470 g of diethyl ether is added dropwise. The mixture is stirred at from −10° C. to 0° C. for 4 hours and then allowed to come to room temperature. After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time and then extracted twice with 1 l of 1M sodium hydroxide solution each time. The alkaline phase is separated off and neutralized with 20% strength sulfuric acid. The crude product is filtered off with suction and, after drying, recrystallized from n-hexane. 66 g (55%) of the title compound are obtained as a pale yellow powder of melting point 107-110° C. to come to room temperature After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time extracted twice with 1 l of 1M sodium hydroxide solution each time The alkaline phase is separated off The crude product is filtered off with suction after drying recrystallized from n-hexane

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

Procedure: Tert-butylethylketone (5 g) was mixed with tert-butylcarbazate (6.4 g, 1.1 eq.) in 30 mL of methanol with 3 drops of acetic acid at room temperature. A solid formed within one hour; more methanol was added, and the mixture was stirred at room temperature for three days to produce N′-(1-ethyl-2,2-dimethyl-propylidene)-hydrazinecarboxylic acid tert-butyl ester. 1H NMR (CDCl3, 500 MHz) δ (ppm): 7.5 (br, 1H), 2.23 (q, 2H)), 1.51 (s, 9H), 1.15 (s, 9H), 1.1 (t, 3H). A solid formed within one hour

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

Procedure: A solution of 40 g of hydrogen chloride in 156 g of diethyl ether is added dropwise at room temperature to 96 g (0.84 mol) of 2,2-dimethyl-3-pentanone in 960 g of toluene. After cooling to −10° C., a solution of 95 g of n-butyl nitrite in 470 g of diethyl ether is added dropwise. The mixture is stirred at from −10° C. to 0° C. for 4 hours and then allowed to come to room temperature. After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time and then extracted twice with 1 l of 1M sodium hydroxide solution each time. The alkaline phase is separated off and neutralized with 20% strength sulfuric acid. The crude product is filtered off with suction and, after drying, recrystallized from n-hexane. 66 g (55%) of the title compound are obtained as a pale yellow powder of melting point 107-110° C. to come to room temperature After a total of 16 h, the reaction mixture is washed three times with 1 l of ice-water each time extracted twice with 1 l of 1M sodium hydroxide solution each time The alkaline phase is separated off The crude product is filtered off with suction after drying recrystallized from n-hexane