反应详情

A suspension of 2-nitro-5-methoxyaniline (3.7 g) in water (25 ml) was heated at 80° C. with 36% hydrochloric acid (7.7 ml) for 30 minutes. It was then treated dropwise with aqueous sodium nitrite solution (1.8 g in 5 ml H2O) at 0° C. After 1 hour, the mixture was filtered and the filtrate added at 23° C. to a solution of dimethylamine (35% aqueous solution, 3.9 ml) and sodium carbonate (8.2 g) in water (340 ml). After 12 hours at 23° C. a solid was collected by filtration and dissolved in benzene (100 ml). The solution was heated under reflux and treated with p-toluene sulphonic acid (4.0 g) and heated under reflux for 4 hours in a Dean-Stark water separator. The reaction mixture stood for 48 hours and was then partitioned between cold 10% aqueous sodium hydroxide solution and dichloromethane. Evaporation of the organic layer left an oil which was purified on silica column using ethylacetate:hexane as eluant to furnish 5-methoxy-2-nitrobiphenyl which was dissolved in ethanol (30 ml) and heated under reflux with sodium sulphide (5.3 g) for 8 hours. Purification of the product on a silica column gave 2-amino-5-methoxybiphenyl which was converted into its hydro-chloride salt (m.p. 167° C.).

1. filtrationthe mixture was filtered
2. additionthe filtrate added at 23° C. to a solution of dimethylamine (35% aqueous solution, 3.9 ml) and sodium carbonate (8.2 g) in water (340 ml)
3. filtrationAfter 12 hours at 23° C. a solid was collected by filtration
4. dissolutiondissolved in benzene (100 ml)
5. temperatureThe solution was heated
6. temperatureunder reflux
7. additiontreated with p-toluene sulphonic acid (4.0 g)
8. temperatureheated
9. temperatureunder reflux for 4 hours in a Dean-Stark water separator
10. waitThe reaction mixture stood for 48 hours
11. customwas then partitioned between cold 10% aqueous sodium hydroxide solution and dichloromethane
12. customEvaporation of the organic layer
13. waitleft an oil which
14. customwas purified on silica column