Reacción #1256757

Ecuación de reacción

2-Amino-5-methylbenzoic acid

pyridine

chloroformate

Methyl chloroformate

→

solid

Rendimiento 31.0%

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

Rendimiento 31.0%

Disolventes

pentane

ethyl acetate

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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.

Fuente