反应详情

温度

-5 °C

A solution of sodium nitrite (0.8 g) in water (20 ml) was added dropwise to a stirred suspension of the product of stage (ii) (3.5 g) in a mixture of concentrated hydrochloric acid (100 ml) and water (100 ml) keeping the temperature below -5° C. The resulting solution was stirred at about -5° C. for 30 min, when a solution of tin (II) chloride dihydrate (13 g) in concentrated hydrochloric acid (100 ml) was added. The resulting suspension was allowed to warm to room temperature over 1 h. The solid was filtered off, washed with ether, and dried in vacuo to give a solid (3.0 g). A sample (2 g) was crystallised from a mixture of methanol and isopropyl acetate to give the title compound as a solid (0.9 g) m.p. 208°-209°.

1. customthe temperature below -5° C
2. temperatureto warm to room temperature over 1 h
3. filtrationThe solid was filtered off
4. washwashed with ether
5. customdried in vacuo