Reaktion #417958

Reaktionsgleichung

2-Amino-5-methylbenzoic acid

pyridine

chloroformate

Methyl chloroformate

→

solid

Ausbeute 31.0%

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

Ausbeute 31.0%

Lösungsmittel

pentane

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

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.

Quelle