Reference of 20781-20-8, A common heterocyclic compound, 20781-20-8, name is (2,4-Dimethoxyphenyl)methanamine, molecular formula is C9H13NO2, 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.
1-(2,4-Dimethoxyphenyl)methanamine (1.97 mL, 13.1 mmol) was added to a solution of 2-methyltetrahydro-4H-pyran-4-one (500 mg, 4.4 mmol) in methanol (10 mL). After stirring for 1 hour at room temperature, the reaction mixture was cooled to -78 C. and a solution of lithium borohydride (98%, 85 mg, 3.8 mmol) in tetrahydrofuran (1.5 mL) was added drop-wise. The reaction mixture was allowed to slowly warm to room temperature overnight, whereupon it was cooled to -20 C. and quenched via careful addition of saturated aqueous sodium bicarbonate solution. Ethyl acetate (25 mL) and sufficient water to solubilize the precipitate were added, and the aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate, filtered, and concentrated in vacuo. Chromatography on silica gel [Gradient: 0% to 15% (10:1 methanol/concentrated ammonium hydroxide) in ethyl acetate] provided the product as a colorless oil. Yield: 936 mg, 3.53 mmol, 80%. 1H NMR (400 MHz, CDCl3) delta 7.13 (d, J=8.0 Hz, 1H), 6.46 (d, half of AB quartet, J=2.2 Hz, 1H), 6.44 (dd, half of ABX pattern, J=8.1, 2.3 Hz, 1H), 4.00 (ddd, J=11.6, 4.6, 1.6 Hz, 1H), 3.82 (s, 3H), 3.81 (s, 3H), 3.76 (s, 2H), 3.37-3.46 (m, 2H), 2.63-2.72 (m, 1H), 1.85-1.92 (m, 1H), 1.78-1.85 (m, 1H), 1.37 (dddd, J=13, 12, 11, 4.6 Hz, 1H), 1.20 (d, J=6.2 Hz, 3H), 1.10 (ddd, J=12, 11, 11 Hz, 1H)
The synthetic route of 20781-20-8 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Pfizer Inc.; Galatsis, Paul; Henderson, Jaclyn Louise; Kormos, Bethany Lyn; Kurumbail, Ravi G.; Reese, Matthew Richard; Stepan, Antonia Friederike; Verhoest, Patrick Robert; Wager, Travis T.; Pettersson, Martin Youngjin; Garnsey, Michelle Renee; (150 pag.)US2017/73343; (2017); A1;,
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