苯甲醛二乙缩醛

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: To a solution of 2-[1-(2-hydroxyethyl)cyclohexyl]propane-1,3-diol (200 mg) in N,N-dimethylformamide (8 mL) were added benzaldehyde diethyl acetal (752 mg) and p-toluenesulfonic acid pyridinium salt (48 mg) at room temperature. After stirring the solution at room temperature for 16 hours, saturated aqueous sodium bicarbonate solution was added thereto, and it was extracted with ethyl acetate. The organic layer was washed in turn with water and saturated aqueous sodium chloride solution (0.2 mL) and dried over anhydrous magnesium sulfate, and then, concentrated under reduced pressure. The resulting residue was purified by chromatography (silica gel, hexane:ethyl acetate=4:6) to give the title compound (100 mg). it was extracted with ethyl acetate The organic layer was washed in turn with water and saturated aqueous sodium chloride solution (0.2 mL) dried over anhydrous magnesium sulfate concentrated under reduced pressure The resulting residue was purified by chromatography (silica gel, hexane:ethyl acetate=4:6)

反应条件: temp:110.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A mixture of imidazole (1.0 g, 14.7 mmol), benzaldehyde diethylacetal (58.8 mmol), and p-toluenesulfonic acid (84 mg, 0.441 mmol) was heated neat at 110° C. for 1-3 days, accompanied by concurrent distillation of ethanol. After cooling, sodium carbonate (0.47 g, 4.41 mmol) was added and the crude mixture was distilled under vacuum (150-170° C./0.5 mmHg) to give N-ethoxybenzylimidazole derivatives (1-8) (15-75% yield). accompanied by concurrent distillation of ethanol After cooling the crude mixture was distilled under vacuum (150-170° C./0.5 mmHg)

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

实验步骤: A solution of benzaldehyde (6.82 mmol), triethyl orthoformate (3.3 g, 22.5 mmol), and conc. HCl (10 μL, 90 μmol) was refluxed in 3.7 mL of ethanol for 24 hrs. Diethyl ether was added and the organic layer was extracted with 3×2 M NaOH. The organic layer was dried over anhydrous Na2SO4. After removal of diethyl ether under reduced pressure, the crude mixture was distilled under vacuum (55-65° C./0.5 mmHg) to give pure benzaldehyde diethylacetal (82-91% yield). All acetals were characterized by 1H-NMR and used without further purification. the organic layer was extracted with 3×2 M NaOH The organic layer was dried over anhydrous Na2SO4 After removal of diethyl ether under reduced pressure the crude mixture was distilled under vacuum (55-65° C./0.5 mmHg)

反应条件: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 1.5 g. helveticoside are dissolved in 20 ml. benzaldehyde diethylacetal and treated with 1.5 g. of a cation exchanger (Lewatit S 100) in the H+-form. The mixture is heated to 55°C while stirring, and the course of the reaction is followed by thin-layer chromatography. After a reaction time of about 4 hours, no more helveticoside can be detected. The ion exchanger is filtered off and the solvent distilled off from the filtrate in a rotating evaporator under vacuum from a water pump. The residue is triturated with petroleum ether. Yield: 950 mg. benzaldehyde-helveticoside, melting point: 202°-210°C (decomposition)⟦alpha.D20 ] (C = 1, chloroform): +25° IR-bands: Aromatic bands at 3030, 3050, 695 and 755 cm-1. Lactone-carbonyl bands at 1740 and 1775 cm-1, aldehyde carbonyl band at 1719 cm-1, C = C double-bond band at 1618 cm-1. λ max. 207 mμ (in CH3OH). After a reaction time of about 4 hours The ion exchanger is filtered off the solvent distilled off from the filtrate in a rotating evaporator under vacuum from a water pump The residue is triturated with petroleum ether +25° IR-bands

反应条件: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 1.5 g. helveticoside are dissolved in 20 ml. benzaldehyde diethylacetal and treated with 1.5 g. of a cation exchanger (Lewatit S 100) in the H+-form. The mixture is heated to 55°C while stirring, and the course of the reaction is followed by thin-layer chromatography. After a reaction time of about 4 hours, no more helveticoside can be detected. The ion exchanger is filtered off and the solvent distilled off from the filtrate in a rotating evaporator under vacuum from a water pump. The residue is triturated with petroleum ether. Yield: 950 mg. benzaldehydehelveticoside, melting point: 202-210°C (decomposition)⟦alpha.D20 ] (C = 1, chloroform):+25° IR-bands: Aromatic bands at 3030, 3050, 695 and 755 cm-1. Lactone-carbonyl bands at 1740 and 1775 cm-1, aldehyde carbonyl band at 1719 cm-1, C = C double-bond band at 1618 cm-1. λ max. 207 m μ (in CH3OH). After a reaction time of about 4 hours The ion exchanger is filtered off the solvent distilled off from the filtrate in a rotating evaporator under vacuum from a water pump The residue is triturated with petroleum ether +25° IR-bands