反応 #417958

反応方程式

2-Amino-5-methylbenzoic acid

pyridine

chloroformate

Methyl chloroformate

→

solid

収率 31.0%

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

収率 31.0%

溶媒

pentane

ethyl acetate

反応条件

後処理

1. 1
   その他prepared above
2. 2
   workup.WAITthe mixture was left
3. 3
   workup.STIRRINGto stir at ambient temperature overnight
4. 4
   洗浄washed with water (15 ml) and 10% aqueous citric acid (20 ml)
5. 5
   抽出The combined aqueous phases were extracted with ethyl acetate (20 ml)
6. 6
   洗浄washed with water (20 ml) and brine (20 ml)
7. 7
   濃縮then concentrated
8. 8
   その他to give a solid
9. 9
   ろ過filtered
10. 10
    ろ過filtered
11. 11
    その他purified by flash chromatography on silica (1.5% diisopropylethylamine in dichloromethane)

実験手順

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.

出典