反应详情

温度

75 °C

A mixture of the title compound of Step B (410 mg, 1.31 mmol), hexamethylenetetramine (256 mg, 2.0 mmol) and trifluoroacetic acid (2.5 ml) under nitrogen was heated to 75° C. and stirred for about three hours. The solution was concentrated in vacuo to give a yellow viscous oil. Water (20 ml) was added to the yellow oil and the mixture was stirred for about 30 minutes at room temperature. The aqueous solution was neutralized with saturated sodium bicarbonate and extracted with ethyl acetate (3×30 ml). The combined organic extracts were washed with saturated sodium bicarbonate (2×50 ml), brine (50 ml), dried, filtered and concentrated to give the title compound (440 mg ) as a crude product which was used in the next step without further purification. NMR (400 MHz, CDCl3) δ10.36 (s, 1H), 7.33 (s, 2H), 7.11-7.16 (m, 2H), 6.93 (d, 1H), 4.39 (s, 2H), 3.86 (s, 3H), 3.40 (s, 3H).

1. concentrationThe solution was concentrated in vacuo
2. customto give a yellow viscous oil
3. stirringthe mixture was stirred for about 30 minutes at room temperature
4. extractionextracted with ethyl acetate (3×30 ml)
5. washThe combined organic extracts were washed with saturated sodium bicarbonate (2×50 ml), brine (50 ml)
6. customdried
7. filtrationfiltered
8. concentrationconcentrated