2,6-dimethyl-2-cyclohexen-1-one

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

Procedure: 2.0 g (0.0161 mole) of 2,6-dimethyl-cyclohex-2-en-1-one, 50 ml of toluene, 1.8 g (0.024 mole) of 2-methoxyethylamine and 0.5 g of palladium on charcoal (5%) are heated with a starting pressure of 17 bars (7 bars propylene and 10 bars nitrogen) for 10 hours at 180° C. After cooling, the catalyst is filtered off and the filter residue is washed with ether and toluene. The solvent is evaporated off to leave 1.0 g of crude N-(2-methoxyethyl)-2,6-dimethylaniline, from which is obtained, by distillation in high vacuum, 0.4 g (13% of theory) of pure N-(2-methoxyethyl)-2,6-dimethylaniline; b.p. 61°-62° C./ 0.1 Torr. After cooling the catalyst is filtered off the filter residue is washed with ether and toluene The solvent is evaporated off

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

Procedure: 19.6 g (0.35 mole) of freshly distilled acrolein is added dropwise at a maximum of 50° C., with ice-cooling, to a solution of 27.8 g (0.2 mole) of N-(3-pent-2-enyl)-pyrrolidine in 50 ml of benzene. After completion of the addition, the mixture is stirred overnight at room temperature; it is subsequently heated for 2 hours at 50°-55° C. and then concentrated by evaporation. The oil remaining is dissolved in 250 ml of 20% hydrochloric acid and the solution is stirred overnight. Extraction is then performed five times with ether; the combined extracts are dried over magnesium sulphate and the ether is distilled off. The crude 2,6-dimethyl-cyclohex-2-en-1-one remaining is purified by vacuum distillation. There is obtained 14.8 g (60% of theory) of 2,6-dimethyl-cyclohex-2-en-1-one, b.p. 62°-64° C./ 10 Torr. After completion of the addition it is subsequently heated for 2 hours at 50°-55° C. concentrated by evaporation The oil remaining is dissolved in 250 ml of 20% hydrochloric acid the solution is stirred overnight Extraction the combined extracts are dried over magnesium sulphate the ether is distilled off The crude 2,6-dimethyl-cyclohex-2-en-1-one remaining is purified by vacuum distillation

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

Procedure: A solution of 19.7 g (0.158 mole) of 2,6-dimethyl-cyclohex-2-en-1-one in 180 ml of conc. ammonia is heated, after the addition of 4.0 g of palladium on charcoal (5%), in a hydrogenating autoclave for 4 hours at 280°-290° C., whereby a pressure of 20 bars is established, and is then maintained under these conditions for 5 hours. Cooling and pressure release are then carried out; the contents are again heated for about 5 hours and the pressure is again released. In order to effect the complete removal of hydrogen, the procedure of heating and pressure release is carried out in all three times. An addition is then made of 150 ml of ether and the catalyst is filtered off. The filter residue is washed three times alternately with 100 ml of ether and water, respectively. The mother liquor is extracted, after separation of the ether phase, five times with 150 ml of ether each time. The combined ether phases are dried over magnesium sulphate. After the ether has been distilled off, there remains 17.0 g of crude 2,6-dimethylaniline, from which is obtained, by distillation in a water-jet vacuum, 12.0 g (63% of theory) of pure 2,6-dimethylaniline; b.p. 103° C./ 18 Torr. is then maintained under these conditions for 5 hours Cooling the contents are again heated for about 5 hours the complete removal of hydrogen the procedure of heating An addition the catalyst is filtered off The filter residue is washed three times alternately with 100 ml of ether and water The mother liquor is extracted after separation of the ether phase, five times with 150 ml of ether each time The combined ether phases are dried over magnesium sulphate After the ether has been distilled off

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

Procedure: 26.1 g (0.168 mole) of N-(3-pent-2-enyl)-morpholine is slowly added dropwise to a solution, cooled to 0°, of 16.8 g (0.3 mole) of freshly distilled acrolein in 150 ml of dioxane, with the temperature rising to 5° C. After completion of the addition, stirring is maintained for half an hour with ice-cooling, and the mixture is then allowed to stand overnight. The solvent is afterwards evaporated off and the oil obtained as residue is dissolved in 120 ml of 20% aqueous hydrochloric acid. On stirring of the acidified solution at room temperature, there precipitates an oil which, after one to two days' stirring, is taken up in ether. The aqueous phase is extracted a further five times with ether. The combined ether phases are dried over magnesium sulphate and the ether is distilled off. There is obtained 18.5 g of crude 2,6-dimethyl-cyclohex-2-en-1-one in the form of oil, which yields, after distillation in a water-jet vacuum, 15.0 g of 2,6-dimethyl-cyclohex-2-en-1-one (72% of theory); b.p. 62°-63° C./ 10 Torr. rising to 5° C After completion of the addition is maintained for half an hour with ice- cooling The solvent is afterwards evaporated off the oil obtained as residue On stirring of the acidified solution at room temperature there precipitates an oil which after one to two days' stirring The aqueous phase is extracted a further five times with ether The combined ether phases are dried over magnesium sulphate the ether is distilled off