5-methylfuran-2-carbaldehyde

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

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

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: 5-Methylfuran-2-carbaldehyde (2.20 g, 20.0 mmol) obtained in Step 1 was dissolved in a mixed solvent of 2-methyl-2-propanol (150 mL) and water (40 mL), and 2-methyl-2-butene (10.6 mL, 100 mmol) and sodium dihydrogenphosphate (2.40 g, 20.0 mmol) were added thereto, followed by stirring at room temperature for 15 minutes. 79% sodium chlorite (8.01 g, 70.0 mmol) was added to the reaction mixture little by little, followed by stirring at room temperature for 1 hour. 4 mol/L hydrochloric acid was added to the reaction mixture to adjust the pH to 3, followed by extraction with chloroform. The organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled away under reduced pressure. The resulting residue was purified through silica gel column chromatography (chloroform:methanol=17:3) to afford 5-methylfuran-2-carboxylic acid (606 mg, 24%). were added by stirring at room temperature for 1 hour followed by extraction with chloroform The organic layer was dried over anhydrous magnesium sulfate the solvent was distilled away under reduced pressure The resulting residue was purified through silica gel column chromatography (chloroform:methanol=17:3)

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

Procedure: Analogously to the building block synthesis of 4-iodomethyl-5-phenyl-2-p-tolyloxazole, diacetylmonoxime and 5-methylfuran-2-carbaldehyde gave 4-iodomethyl-5-methyl-2-(5-methylfuran-2-yl)oxazole.

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

Procedure: Analogously to the building block synthesis of 4-iodomethyl-5-phenyl-2-p-tolyloxazole, diacetylmonoxime and 5-methylfuran-2-carbaldehyde gave 4-iodomethyl-5-methyl-2-(5-methylfuran-2-yl)oxazole.

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

Procedure: A mixture of 5-methylfuran-2-carboxaldehyde (5.51 g, 50 mmol, purchased from Wako Junyaku Kogyo), rhodanine (6.66 g, 50 mmol, purchased from Tokyo Kase), and anhydrous sodium acetate (2.3 g, 150 mmol, purchased from Kokusan Kagaku) in 35 ml of acetic acid (purchased from Wako Junyaku Kogyo) was refluxed for 30 minutes. After being cooled, the reaction mixture was poured into 500 ml of water. The precipitate was collected and washed with water, with ethanol, and then with ether to give 10.04 g (yield: 89.1%) of (5-methylfurylidene) rhodanine as an orange-brown color crystalline. was refluxed for 30 minutes After being cooled The precipitate was collected washed with water, with ethanol

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

Procedure: A mixture of 5-methylfuran-2-carboxaldehyde (5.51 g, 50 mmol, purchased from Wako Junyaku Kogyo), rhodanine (6.66 g, 50 mmol, purchased from Tokyo Kase), and anhydrous sodium acetate (2.3 g, 150 mmol, purchased from Kokusan Kagaku) in 35 ml of acetic acid (purchased from Wako Junyaku Kogyo) was refluxed for 30 minutes. After being cooled, the reaction mixture was poured into 500 ml of water. The precipitate was collected and washed with water, with ethanol, and then with ether to give 10.04 g (yield: 89.1%) of (5-methylfurylidene) rhodanine as an orange-brown color crystalline. was refluxed for 30 minutes After being cooled The precipitate was collected washed with water, with ethanol

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

Procedure: Under an atmosphere of nitrogen, 10 ml of tetrahydrofuran and 10 mg of iodine were mixed with 3.974 g of magnesium flakes. With stirring, 3 ml of a solution prepared by dissolving 22.28 g of ethyl bromide in 25 ml of tetrahydrofuran was added dropwise to the mixture. The residual tetrahydrofuran solution of ethyl bromide was added dropwise to the reaction vessel placed in a water bath over one hour. After stirring for thirty minutes, a solution prepared by dissolving 15 g of 5-methyl-2-furaldehyde in 5 ml of tetrahydrofuran was added dropwise to the reaction solution over five minutes under ice-water cooling. After one hour, the reaction solution was added to a cooled 10% ammonium chloride solution and stirred for five minutes. The mixed solution was extracted twice with diethyl ether. The combined ether layer was washed twice with a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the residue was distilled, and a distillate fraction of 95° to 98° C. at 22 mmHg was collected to yield 28.977 g of 1-(5-methyl-2-furyl)propanol. Yield 91% was added dropwise to the mixture After stirring for thirty minutes a solution prepared was added dropwise to the reaction solution over five minutes under ice-water cooling After one hour stirred for five minutes The mixed solution was extracted twice with diethyl ether The combined ether layer was washed twice with a saturated sodium chloride solution dried over anhydrous magnesium sulfate After removal of the solvent under reduced pressure the residue was distilled a distillate fraction of 95° to 98° C. at 22 mmHg was collected

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

Procedure: Under an atmosphere of nitrogen, 10 ml of tetrahydrofuran and 10 mg of iodine were mixed with 3.974 g of magnesium flakes. With stirring, 3 ml of a solution prepared by dissolving 22.28 g of ethyl bromide in 25 ml of tetrahydrofuran was added dropwise to the mixture. The residual tetrahydrofuran solution of ethyl bromide was added dropwise to the reaction vessel placed in a water bath over one hour. After stirring for thirty minutes, a solution prepared by dissolving 15 g of 5-methyl-2-furaldehyde in 5 ml of tetrahydrofuran was added dropwise to the reaction solution over five minutes under ice-water cooling. After one hour, the reaction solution was added to a cooled 10% ammonium chloride solution and stirred for five minutes. The mixed solution was extracted twice with diethyl ether. The combined ether layer was washed twice with a saturated sodium chloride solution, and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the residue was distilled, and a distillate fraction of 95° to 98° C. at 22 mmHg was collected to yield 28.977 g of 1-(5-methyl-2-furyl)propanol. Yield 91% was added dropwise to the mixture After stirring for thirty minutes a solution prepared was added dropwise to the reaction solution over five minutes under ice-water cooling After one hour stirred for five minutes The mixed solution was extracted twice with diethyl ether The combined ether layer was washed twice with a saturated sodium chloride solution dried over anhydrous magnesium sulfate After removal of the solvent under reduced pressure the residue was distilled a distillate fraction of 95° to 98° C. at 22 mmHg was collected

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

Procedure: To a suspension of triphenyl-(3-ethoxycarbonylpropyl)phosphonium bromide (2.27 g, 5 mmol) and 5-methylfurfural (0.55 g, 5 mmol) in 5 mL of dry tetrahydrofuran, a 1 M solution of sodium bis(trimethylsilyl)amide in tetrahydrofuran (5 mL) was added dropwise. The reaction mixture was stirred at room temperature for 2 hours and quenched with 2 N hydrochloric acid solution. The reaction mixture was extracted with ethyl acetate and the combined organic layers were dried over magnesium sulfate, concentrated and chromatographed eluting with 5% ethyl acetate/hexane to yield the title product: 1H NMR (300 MHz, CDCl3) δ 6.16 (d, J=3.05 Hz, 1H), 5.97 (dd, J=3.22, 0.85 Hz, 1H), 5.42 (dt, J=11.44, 7.11 Hz, 1H)), 4.14 (q, J=7.2 Hz, 2H), 2.76 (m, 2H), 2.47 (t, J=7.46 Hz, 2H), 2.31 (s, 3H), 1.25 (t, J=7.12 Hz, 3H); MS (DCI/NH3)(M+H)+ m/z 209. quenched with 2 N hydrochloric acid solution The reaction mixture was extracted with ethyl acetate the combined organic layers were dried over magnesium sulfate concentrated chromatographed eluting with 5% ethyl acetate/hexane