反应详情

To a suspension of 4,4-dimethyl-2-(1-oxo-1,3-dihydroisobenzofuran-5-yl)oxazoline (23.1 g, 0.1 mol) in thionyl chloride (36 mL) is slowly added N,N-dimethylformamide (5 ml). The solution is heated at reflux for 1 hour and then allowed to cool to room temperature over 3 hours. Then toluene (150 mL) is added and the suspension is filtered and washed with toluene (2×50 mL). The wet crystals are taken into deionized water (150 mL) and the pH is adjusted to 8.0 with 25% aqueous ammonia. The solid is filtered and washed with deionized water (2×50 mL) and dried at 60° C. under reduced pressure. Yield: 11.9 g (75%) of an off-white product having a purity (HPLC, peak area)=92%. An analytical pure sample is obtained by crystallisation from acetic acid or toluene. 1H NMR (DMSO d-6, 500 MHz): 5.48 (2H, s), 8.04 (2H, s+s), 8.22 (1H, s).

1. temperatureThe solution is heated
2. temperatureat reflux for 1 hour
3. filtrationthe suspension is filtered
4. washwashed with toluene (2×50 mL)
5. filtrationThe solid is filtered
6. washwashed with deionized water (2×50 mL)
7. customdried at 60° C. under reduced pressure
8. customAn analytical pure sample is obtained by crystallisation from acetic acid or toluene