2,5-二甲基-3-呋喃酸甲酯

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

实验步骤: 154 g (1 mole) of methyl 2,5-dimethylfuran-3-carboxylate and 157 g (1 mole) of 4-hydroxy-2,2,6,6-tetramethylpiperidine were heated together with 10 g of tetrabutyl orthotitanate for 10 hours at about 190° C., the methanol formed being distilled off. When the reaction is complete, the mixture is cooled and the reaction mass is dissolved in ethyl acetate. The solution is extracted by shaking, first with 10% strength sodium carbonate solution and then with water, after which it is dried and evaporated down, and the residue is distilled under reduced pressure. The desired product distils at 142° C./2 mm as a virtually colorless oil which soon solidifies to a solid of melting point 59°-61° C. being distilled off the mixture is cooled the reaction mass is dissolved in ethyl acetate The solution is extracted with water, after which it is dried evaporated down the residue is distilled under reduced pressure The desired product distils at 142° C./2 mm as a virtually colorless oil which

反应条件: temp:0.00; pressure:0.00; stir:

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

实验步骤: 40 parts by weight of iron-III chloride and 136 parts by weight of 85 percent strength α-acetoxypropionaldehyde are added successively to a solution of 150 parts by weight of methyl acetoacetate in 120 parts by weight of methanol. The mixture, which becomes warm, is then refluxed for 2 hours. When it has cooled, the reaction solution is washed with water and distilled. 127 g of 2,5-dimethylfuran-3-carboxylic acid methyl ester are obtained. The mixture, which becomes warm is then refluxed for 2 hours When it has cooled the reaction solution is washed with water distilled

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

实验步骤: 27 parts by weight of iron-III chloride and 149 parts by weight of 85.5 percent strength α-acetoxypropionaldehyde are added to a solution of 116 parts by weight of methyl acetoacetate in 120 parts by weight of methanol at a rate such that the mixture rises to the boil. The methanol is distilled off under atmospheric pressure and the product is then distilled under reduced pressure. 106.2 parts by weight of 2,5-dimethylfuran-3-carboxylic acid methyl ester, of boiling point 89° C./20 mbar, are obtained. The methanol is distilled off under atmospheric pressure the product is then distilled under reduced pressure

反应条件: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 27 parts by weight of anhydrous iron-III chloride are added to a solution of 116 parts by weight of methyl acetoacetate in 120 parts by weight of methanol and thereafter 149 parts by weight of 85.5 percent strength α-acetoxypropionaldehyde are added dropwise, sufficiently slowly that the temperature does not rise above 37° C. The mixture is stirred overnight at room temperature (20° C.), is then boiled for 2 hours, and, when it has cooled, is worked up as described in Example 1. Distillation gives 116.6 parts by weight of 2,5-dimethylfuran-3-carboxylic acid methyl ester. does not rise above 37° C is then boiled for 2 hours when it has cooled Distillation

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

实验步骤: 12.2 parts by weight of anhydrous iron-III chloride followed by 44.9 parts by weight of 85.5 percent strength by weight α-acetoxypropionaldehyde are added to a solution of 34.8 parts by weight of methyl acetoacetate in 36 parts by weight of methanol, during which addition the mixture rises to the boil. The mixture is then refluxed for a further 1-6 hours and, when it has cooled, is mixed with 80 parts by weight of water and 37.5 parts by weight of dichloroethane; the water phase is separated off and is extracted twice, each time with 25 parts by weight of dichloroethane. The dichloroethane is distilled off under atmospheric pressure and the product is then distilled under reduced pressure. 39 parts by weight of 2,5-dimethylfuran-3-carboxylic acid methyl ester of boiling point 92° C./26 mbar are obtained. The mixture is then refluxed for a further 1-6 hours when it has cooled the water phase is separated off is extracted twice The dichloroethane is distilled off under atmospheric pressure the product is then distilled under reduced pressure

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

实验步骤: To a 0° C. solution of methyl 2,5-dimethyl-3-furanoate (2.0 g, 13.0 mmol) in THF (130 mL) under N2 was added lithium aluminum hydride (39 mL of a 1.0 M solution in THF, 38.9 mmol) dropwise. The reaction was stirred at 0° C. for 3.5 h, at which time it was quenched cautiously with saturated aqueous Na2SO4 solution and allowed to warm to room temperature. The reaction mixture was filtered and rinsed with ethyl acetate, the filtrate was diluted with more ethyl acetate and the layers separated. The organic layer was washed with saturated aqueous NH4Cl, water and brine and dried over Na2SO4. The solution was filtered and concentrated to afford the title compound as a clear liquid (1.54 g, 12.2 mmol, 94%). 1H NMR (300 MHz, DMSO-d6): δ 5.93 (s, 1H); 4.18 (s, 2H); 2.17 (s, 3H); 2.15 (s, 3H). was quenched cautiously with saturated aqueous Na2SO4 solution to warm to room temperature The reaction mixture was filtered rinsed with ethyl acetate the filtrate was diluted with more ethyl acetate the layers separated The organic layer was washed with saturated aqueous NH4Cl, water and brine dried over Na2SO4 The solution was filtered concentrated

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

实验步骤: To a stirred solution of 3-carbomethoxy-2,5-dimethylfuran (2.5 g, 16.2 mmol) in methylene chloride (distilled from CaH) at -20° C., under N2, was added 2.5 eq of DIBAL (1M in CH2Cl2). After 1 h, the dry ice/acetonitrile bath was removed and 60 mL of 10% HCl was added dropwise. The organic layer was separated, dried over MgSO4, and evaporated. The residue was chromatographed (silica gel, 60% ether/hexane) to yield 1.3 g of 2,5-dimethyl-3- hydroxymethylfuran. the dry ice/acetonitrile bath was removed 60 mL of 10% HCl was added dropwise The organic layer was separated dried over MgSO4 evaporated The residue was chromatographed (silica gel, 60% ether/hexane)

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

实验步骤: 154 g (1 mole) of methyl 2,5-dimethylfuran-3-carboxylate and 157 g (1 mole) of 4-hydroxy-2,2,6,6-tetramethylpiperidine were heated together with 10 g of tetrabutyl orthotitanate for 10 hours at about 190° C., the methanol formed being distilled off. When the reaction is complete, the mixture is cooled and the reaction mass is dissolved in ethyl acetate. The solution is extracted by shaking, first with 10% strength sodium carbonate solution and then with water, after which it is dried and evaporated down, and the residue is distilled under reduced pressure. The desired product distils at 142° C./2 mm as a virtually colorless oil which soon solidifies to a solid of melting point 59°-61° C. being distilled off the mixture is cooled the reaction mass is dissolved in ethyl acetate The solution is extracted with water, after which it is dried evaporated down the residue is distilled under reduced pressure The desired product distils at 142° C./2 mm as a virtually colorless oil which