Реакция #417958

Уравнение реакции

2-Amino-5-methylbenzoic acid

pyridine

chloroformate

Methyl chloroformate

→

solid

Выход 31.0%

2-Hexadecyloxy-6-methyl-4H-3,1-benzoxazin-4-one

Выход 31.0%

Растворители

pentane

ethyl acetate

Условия реакции

Обработка

1. 1
   Другоеprepared above
2. 2
   workup.WAITthe mixture was left
3. 3
   workup.STIRRINGto stir at ambient temperature overnight
4. 4
   Промывкаwashed with water (15 ml) and 10% aqueous citric acid (20 ml)
5. 5
   ЭкстракцияThe combined aqueous phases were extracted with ethyl acetate (20 ml)
6. 6
   Промывкаwashed with water (20 ml) and brine (20 ml)
7. 7
   Концентрированиеthen concentrated
8. 8
   Другоеto give a solid
9. 9
   Фильтрацияfiltered
10. 10
    Фильтрацияfiltered
11. 11
    Другоеpurified by flash chromatography on silica (1.5% diisopropylethylamine in dichloromethane)

Методика

2-Amino-5-methylbenzoic acid (2.71 g, 17.9 mmol, 0.87 eq.) was dissolved in pyridine (24 ml) and added to the chloroformate solution prepared above. The mixture was stirred at room temperature for 1.75 hours. Methyl chloroformate (13.6 ml, 176 mmol, 8.5 eq) was added slowly, then the mixture was left to stir at ambient temperature overnight. The mixture was diluted with ethyl acetate (20 ml) and washed with water (15 ml) and 10% aqueous citric acid (20 ml). The combined aqueous phases were extracted with ethyl acetate (20 ml). The organic extracts were combined and washed with water (20 ml) and brine (20 ml) then concentrated to give a solid. This was slurried in pentane (5 ml), filtered, then slurried in acetonitrile (5 ml), filtered and purified by flash chromatography on silica (1.5% diisopropylethylamine in dichloromethane) to give a white solid (2.51 g, 31%) δH (400 MHz, CDCl3) 0.87 (3H, t, J 6.8, CH2CH3), 1.24-1.45 (26H, m, 13×CH2), 1.75-1.83 (2H, m, OCH2CH2), 2.41 (3H, s, ArCH3), 4.41 (2H, t, J 6.7, OCH2), 7.30 (1H, d, J 8.3, ArH), 7.51 (1H, dd, J 8.5, 2.0, ArH), 7.90 (1H, d, J 1.1, ArH); m/z (ES+) 402 (MH+); MPt. 72-73° C.

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