The synthetic route of 3,5-Dimethoxytoluene has been constantly updated, and we look forward to future research findings.
A common heterocyclic compound, 4179-19-5, name is 3,5-Dimethoxytoluene, molecular formula is C9H12O2, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. 4179-19-5.
To a 3-necked, round-bottomed flask was added 3,5-dimethoxytoluene (6.088 g, 40 mmol) and cyclohexane (28 mL) under nitrogen. Dimethyl carbonate (30.3 g, 336 mmol) was added and the reaction mixture was heated at 60 C. Excess chlorosulfonic acid was added over a period of 15 min. The liberated HCl gas was removed by inserting a tube into solid sodium hydroxide. On completion of the addition, the reaction mixture was heated to 70-72 C. for 1 h and then cooled to room temperature. The solid was filtered off and washed with dimethyl carbonate/cyclohexane (1:1, 20 mL). The solid was dried in vacuo to obtain pure material (6.13 g, 66%). To a mixture of the sulfonic acid (product from above, 4.65 g, 20 mmol) and triethyl amine (2.03 g, 2.79 mL) in acetone (40 mL) was added 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride, 3.69 g, 20 mmol). The reaction mixture was heated under reflux for 20 h before being cooled to room temperature. The solution was passed through a Celite pad and evaporated in vacuo to leave a solid, which was filtered off and washed with hexane. The mixture of product and salt of cyanuric hydroxide and triethyl amine (7.58 g) was used for the next step without further purification.To a 3-necked, round-bottomed flask, equipped with a condenser (acetone-dry ice cooling), was added the mixture from the step above (7.58 g) and acetone (100 mL). The reaction mixture was cooled to -78 C. and ammonia gas was bubbled through the solution for 0.5 h. The reaction mixture was kept standing overnight, allowing slow evaporation of ammonia gas, followed by the evaporation of solvent. Water was added and the product was extracted with DCM. The solvent was dried and evaporated to leave a mixture of solid and a dense liquid. The solid was filtered off and washed with hexane to leave pure sulfonamide (3.23 g, 70%).To a round-bottomed flask was added 3,5-dimethyl-4-hydroxybenzoic acid (2.99 g, 18 mmol). Anhydrous DMF (20 mL) was added, followed by sodium hydride (1.8 g, 45 mmol). The reaction mixture was stirred at room temperature for 1 h. p-Methoxybenzyl chloride (6.20 g, 39.6 mmol) was added and the mixture was stirred at room temperature overnight (20 h). The reaction mixture was poured into water, acidified with 1 N HCl and stirred for 1 h. The precipitated solid was filtered off, washed with water and hexane to obtain pure B-ring building block (6.93 g, 95%).The B-ring building block (6.93 g, 17.1 mmol) was dissolved in a mixture of methanol (50 mL) and tetrahydrofuran (50 mL). Potassium hydroxide (1.25 g, 22.2 mmol) in water (20 mL) was added. The reaction mixture was refluxed at 70 C. for 24 h. The solvent was evaporated in vacuo. Water was added and the reaction mixture was acidified with 1 N HCl (pH 4-5). The solid was filtered off, washed with water and hexane. The yield was 4.61 g (94%). The product (1.932 g, 6.75 mmol) and the sulfonamide from above (1.04 g, 4.5 mmol) were taken in a 3-necked, round-bottomed flask under nitrogen. Dichloromethane (100 mL) was added with stirring. To this stirred mixture was added N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDCl. HCl, 1.36 g, 7.09 mmol), followed by N,N-dimethylaminopyridine (2.06 g, 16.9 mmol). The reaction mixture was stirred at room temperature for 24 h before being washed with 1 N HCl, 2.5% NaOH and saturated sodium bicarbonate solutions. The organic layers were dried and evaporated in vacuo to leave a residue, which was purified by silica gel (100 g) column chromatography, employing 20-50% ethyl acetate in hexane and 5% methanol in dichloromethane as eluents. Fractions 30-66 were combined to obtain pure materials (1.35 g, 60%). The compound from the step above (0.105 g, 0.21 mmol) was dissolved in tetrahydrofuran under nitrogen and cooled to -78 C. n-Butyllithium was added and the reaction mixture was allowed to warm to room temperature slowly and stirred overnight (14 h). TLC showed incomplete conversion. The reaction mixture was quenched with saturated ammonium chloride solution and extracted with ethyl acetate. The solvent was evaporated in vacuo to leave a residue that was purified by silica gel (15 g) column chromatography, employing 20-50% ethyl acetate in hexane as eluents. The product was not pure enough, so another column was used, employing 0.5% methanol in hexane as eluent, and finally preparative TLC was employed to purify the material. The compound from the step above (0.277 g) was dissolved in trifluoroacetic acid (10 mL) under nitrogen and the reaction mixture was refluxed (bath temperature 80 C.) for 4 d. The solvent was evaporated in vacuo and the residue was dissolved in 0.25 N NaOH (20 mL), and acidified with acetic acid. The solid had precipitated out at this point. The solid was filtered off and washed with water, hexane and dried. From one batch, 0.005 g of pure material was isolated. From another batch, 0.060 g compound was isolated, which was not pure enough. This compound was further purified by preparat…
The synthetic route of 3,5-Dimethoxytoluene has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Wong, Norman C.W.; Tucker, Joseph E.L.; Hansen, Henrik C.; Chiacchia, Fabrizio S.; McCaffrey, David; US2008/188467; (2008); A1;,
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