反应详情

To a mixture of the product from Step C (16.0 g, 56.1 mmol) in acetic acid/water (150 mL/30 mL) at 0° C. was added sodium nitrite (7.75 g, 112 mmol) in portions over 40 min. The mixture was stirred for 50 min, cooled (ice bath), and zinc (14.7 g, 224 mmol) was added in portions. After 1 h the suspension was warmed to room temperature and more zinc was added (14.7 g, 224 mmol). The mixture was stirred for 1 h, concentrated, and extracted with EtOAc (2×300 mL). The extracts were filtered through a filter-aide, and the filtrate was washed with saturated aqueous disodium hydrogen phosphate (to pH 8) and brine, dried, and purifed by chromatrography (silica, 25% EtOAc/hexane) to afford an oil (7.01 g, 44%).

1. additionwas added in portions
2. stirringThe mixture was stirred for 1 h
3. concentrationconcentrated
4. extractionextracted with EtOAc (2×300 mL)
5. filtrationThe extracts were filtered through a filter-aide
6. washthe filtrate was washed with saturated aqueous disodium hydrogen phosphate (to pH 8) and brine
7. customdried