反应 #554666

反应方程式

Methanesulfonic acid

3-methyltetrahydro-4H-pyran-4-one

Sodium azide

→

3-methyl-1,4-oxazepan-5-one

溶剂

DME

反应条件

后处理

1. 1
   其他prepared by the method of Smith
2. 2
   其他at −40° C
3. 3
   温度as cooling
4. 4
   温度was maintained
5. 5
   其他The cold bath was then removed
6. 6
   workup.ADDITIONThe mixture was diluted with DME (20 mL)
7. 7
   其他The resulting mixture was partitioned between brine (200 mL)
8. 8
   干燥The combined organic layers were dried over sodium sulfate
9. 9
   浓缩concentrated

实验过程

Methanesulfonic acid (20 mL) was added to a solution of 3-methyltetrahydro-4H-pyran-4-one (4-1, prepared by the method of Smith, A. B. et al. J. Am. Chem. Soc. 1991, 113, 2071, 3.00 g, 26.3 mmol, 1 equiv) in DME (30 mL) at −40° C. Sodium azide (5.13 g, 79.0 mmol, 3.00 equiv) was added in four equal portions over 30 min as cooling was maintained. The cold bath was then removed and the reaction mixture was warmed to 23° C. and stirred for 20 h. The mixture was diluted with DME (20 mL) and basified to pH 9 with concentrated aqueous ammonium hydroxide solution. The resulting mixture was partitioned between brine (200 mL) and a solution of 10% n-propanol in ethyl actetate (2×400 mL). The combined organic layers were dried over sodium sulfate and concentrated to give 3-methyl-1,4-oxazepan-5-one (4-2) as a pasty white solid. 1H NMR (300 MHz, CDCl3) δ 5.73 (br s, 1H), 3.97 (ddd, 1H,J=12.4, 5.6, 2.8 Hz), 3.83 (d, 1H,J=12.2 Hz), 3.76 (m, 1H), 3.66 (dd, 1H,J=12.4, 10.8 Hz), 3.35 (dd, 1H, J=12.2, 8.2 Hz), 2.89 (ddd, 1H,J=15.8, 10.8, 2.8 Hz), 2.54 (dd, 1H,J=15.8, 5.6 Hz), 1.15 (d, 3H,J=7.1 Hz).

来源