Réaction #1256757

Équation de réaction

2-Amino-5-methylbenzoic acid

pyridine

chloroformate

Methyl chloroformate

→

solid

Rendement 31.0%

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

Rendement 31.0%

Solvants

pentane

ethyl acetate

Conditions de réaction

Traitement

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

Mode opératoire

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.

Source