2-methylpentanal

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

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

Procedure: After dissolving 7.0 g of sodium hydroxide in 50 ml of water and 50 ml of ethanol at 4° C., 10.7 g of nitromethane and 10.0 g of 2-methylpentanal were added thereto. The temperature of the solution was allowed to rise to room temperature, and the solution was stirred for two hours. After concentrating the ethanol under reduced pressure, the solution was neutralized with 1 mol/l of hydrochloric acid so that the pH of the solution was approximately 7. Ethyl acetate was added to the solution, and the organic layer was washed with saturated saline. The organic layer was dried with magnesium sulfate and concentrated, and then purified by silica gel chromatography (hexane/ethyl acetate=8/1), thereby obtaining 13.3 g of 3-methyl-1-nitro-2-hexanol (yield: 94.2%). to rise to room temperature After concentrating the ethanol under reduced pressure Ethyl acetate was added to the solution the organic layer was washed with saturated saline The organic layer was dried with magnesium sulfate concentrated purified by silica gel chromatography (hexane/ethyl acetate=8/1)

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

Procedure: is a known synthetic perfume obtainable from 2-methyl pentanal 23 (cf. following scheme). The educt 23 is reacted with 2 equivalents of formaldehyde in a crossed Canizzaro reaction to form 2-methyl-2-propylpropane-1,3-diol 24. The diol 24 may then be acetalized with 2-methylpentanal 23 to form Troënan® 22.

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

Procedure: Malonic acid (44 g, 0.42 mol), 2-methylpentan-1-al (14 g, 0.14 mol) and piperidine (1.7 ml) were suspended in 85 ml pyridine and heated under reflux. Gas formation was observed which ceased after two hours. Heating was continued for 1 hour. The cooled reaction mixture was poured into 2M hydrochloric acid (200 ml) after which two phases were obtained which were separated in a separating funnel. The aqueous phase was extracted once with dichloromethane (60 ml). The organic phases were combined and the solvent removed under reduced pressure. The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate). 9.3 g (0.065 mol, 47% yield) of (E)-4-methyl-hept-2-enoic acid were obtained as a solid. NMR (1H, CDCl3, 300 MHz): 11.86 (s, 1H), 7.00 (dd, 1H), 5.79 (d, 1H), 2.35 (m, 1H), 1.35 (m, 4H), 1.06 (d, 3H), 0.89 (m, 3H). heated under reflux Heating was continued for 1 hour The cooled reaction mixture were obtained which were separated in a separating funnel The aqueous phase was extracted once with dichloromethane (60 ml) the solvent removed under reduced pressure The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate)

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 126 g (1.5 moles) of cyclopentanone, 50 g (0.5 mole) of 2-methylpentanal and 10 g of a pulverulent catalyst containing 1% by weight of palladium, 94% by weight of alumina and 5% by weight of praseodymium oxide was initially taken in a 300 ml autoclave. The autoclave was flushed with nitrogen and hydrogen at 20° C., after which H2 was forced in to a pressure of 10 bar and the reaction mixture was then heated at 150° C. under a hydrogen pressure of 30 bar until the pressure remained constant. The catalyst was removed, after which the mixture discharged from the autoclave was fractionated. 74.9 g of pure 2-(2-methylpentyl)-cyclopentanone (bp. 125° C./20 mbar) were obtained, corresponding to a selectivity of 89.2%, based on 2-methylpentanal. The autoclave was flushed with nitrogen and hydrogen at 20° C. The catalyst was removed

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

Procedure: Using the method described in Example 1(b), one part per hour of a 72 percent strength by weight aqueous solution of 2-methyl-2-propyl-3-hydroxypropanal is hydrogenated, over the catalyst prepared as described in Example 1(a), at 130° C. and 30 bar, with a throughput of 0.36 part of 2-methyl-2-propyl-3-hydroxypropanal per liter of catalyst per hour. The conversion is 89.5 percent. The hydrogenated material is fractionated through a packed column. After first runnings of water and small amounts of methanol, 2-methylpentanal and 2-methyl-2-propyl-3-hydroxypropanal, 2-methyl-2-propyl-propane-1,3-diol, of boiling point 112°-113° C./5 mbar (melting point 58°-60° C.), is obtained in an amount corresponding to 0.6967 part per hour. This is equivalent to a yield of 95.3% of theory, based on starting material. prepared as described in Example 1(a), at 130° C.

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

Procedure: Using the method described in Example 1(b), one part per hour of a 72 percent strength by weight aqueous solution of 2-methyl-2-propyl-3-hydroxypropanal is hydrogenated, over the catalyst prepared as described in Example 1(a), at 130° C. and 30 bar, with a throughput of 0.36 part of 2-methyl-2-propyl-3-hydroxypropanal per liter of catalyst per hour. The conversion is 89.5 percent. The hydrogenated material is fractionated through a packed column. After first runnings of water and small amounts of methanol, 2-methylpentanal and 2-methyl-2-propyl-3-hydroxypropanal, 2-methyl-2-propyl-propane-1,3-diol, of boiling point 112°-113° C./5 mbar (melting point 58°-60° C.), is obtained in an amount corresponding to 0.6967 part per hour. This is equivalent to a yield of 95.3% of theory, based on starting material. prepared as described in Example 1(a), at 130° C.

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

Procedure: After dissolving 7.0 g of sodium hydroxide in 50 ml of water and 50 ml of ethanol at 4° C., 10.7 g of nitromethane and 10.0 g of 2-methylpentanal were added thereto. The temperature of the solution was allowed to rise to room temperature, and the solution was stirred for two hours. After concentrating the ethanol under reduced pressure, the solution was neutralized with 1 mol/l of hydrochloric acid so that the pH of the solution was approximately 7. Ethyl acetate was added to the solution, and the organic layer was washed with saturated saline. The organic layer was dried with magnesium sulfate and concentrated, and then purified by silica gel chromatography (hexane/ethyl acetate=8/1), thereby obtaining 13.3 g of 3-methyl-1-nitro-2-hexanol (yield: 94.2%). to rise to room temperature After concentrating the ethanol under reduced pressure Ethyl acetate was added to the solution the organic layer was washed with saturated saline The organic layer was dried with magnesium sulfate concentrated purified by silica gel chromatography (hexane/ethyl acetate=8/1)

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

Procedure: is a known synthetic perfume obtainable from 2-methyl pentanal 23 (cf. following scheme). The educt 23 is reacted with 2 equivalents of formaldehyde in a crossed Canizzaro reaction to form 2-methyl-2-propylpropane-1,3-diol 24. The diol 24 may then be acetalized with 2-methylpentanal 23 to form Troënan® 22.

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

Procedure: Malonic acid (44 g, 0.42 mol), 2-methylpentan-1-al (14 g, 0.14 mol) and piperidine (1.7 ml) were suspended in 85 ml pyridine and heated under reflux. Gas formation was observed which ceased after two hours. Heating was continued for 1 hour. The cooled reaction mixture was poured into 2M hydrochloric acid (200 ml) after which two phases were obtained which were separated in a separating funnel. The aqueous phase was extracted once with dichloromethane (60 ml). The organic phases were combined and the solvent removed under reduced pressure. The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate). 9.3 g (0.065 mol, 47% yield) of (E)-4-methyl-hept-2-enoic acid were obtained as a solid. NMR (1H, CDCl3, 300 MHz): 11.86 (s, 1H), 7.00 (dd, 1H), 5.79 (d, 1H), 2.35 (m, 1H), 1.35 (m, 4H), 1.06 (d, 3H), 0.89 (m, 3H). heated under reflux Heating was continued for 1 hour The cooled reaction mixture were obtained which were separated in a separating funnel The aqueous phase was extracted once with dichloromethane (60 ml) the solvent removed under reduced pressure The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate)

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

Procedure: Malonic acid (44 g, 0.42 mol), 2-methylpentan-1-al (14 g, 0.14 mol) and piperidine (1.7 ml) were suspended in 85 ml pyridine and heated under reflux. Gas formation was observed which ceased after two hours. Heating was continued for 1 hour. The cooled reaction mixture was poured into 2M hydrochloric acid (200 ml) after which two phases were obtained which were separated in a separating funnel. The aqueous phase was extracted once with dichloromethane (60 ml). The organic phases were combined and the solvent removed under reduced pressure. The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate). 9.3 g (0.065 mol, 47% yield) of (E)-4-methyl-hept-2-enoic acid were obtained as a solid. NMR (1H, CDCl3, 300 MHz): 11.86 (s, 1H), 7.00 (dd, 1H), 5.79 (d, 1H), 2.35 (m, 1H), 1.35 (m, 4H), 1.06 (d, 3H), 0.89 (m, 3H). heated under reflux Heating was continued for 1 hour The cooled reaction mixture were obtained which were separated in a separating funnel The aqueous phase was extracted once with dichloromethane (60 ml) the solvent removed under reduced pressure The residue was purified by column chromatography (pre-packed silica column, gradient of pentane/ethyl acetate)

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 800 parts of 2-methylpentanal, 800 parts of xylene and 120 parts of urea is heated to the boil in a stirred apparatus of the type described in Example 1, and 50 parts of 75% strength sulfuric acid are added dropwise. The mixture is then stirred at the boil and the water formed (84 parts) is removed via the water separator. The condensation is complete after about 3 hours. The reaction mixture is neutralized with 50% strength sodium hydroxide solution and stirred for a further hour at the boil, whilst removing water. 60 Parts of 30% strength sodium methylate solution in methanol are then added to the contents of the flask and the mixture is again stirred for 1 hour at the boil. It is then cooled to 60° C., neutralized to pH 7 with 75% strength sulfuric acid and washed with twice 1,000 parts of water. After removing the wash water, the xylene solution is evaporated under reduced pressure (20-25 mm Hg) until the temperature in the flask reaches 175° C. is heated to the boil in a stirred apparatus of the type are added dropwise is removed via the water separator stirred for a further hour at the boil whilst removing water 60 Parts of 30% strength sodium methylate solution in methanol are then added to the contents of the flask the mixture is again stirred for 1 hour at the boil washed with twice 1,000 parts of water After removing the wash water the xylene solution is evaporated under reduced pressure (20-25 mm Hg) until the temperature in the flask reaches 175° C.