2,3-二氟-4-碘苯甲醚的合成

以2,3-二氨基苯甲醚为原料,在浓HC l和NaNO2作用下,反应温度在5℃以下,加入w(HBF4)=40%的氟硼酸,加热,经Sch iem ann反应生成2,3-二氟苯甲醚,产率40.7%。然后在50~60℃水浴中缓慢滴加w(HNO3)=65%~68%的发烟硝酸、冰醋酸和醋酐的混合液,苯环上4-位硝化后得2,3-二氟-4-硝基苯甲醚,产率51.9%,熔点124℃。在SnC l2和浓HC l作用下反应12 h,再还原成2,3-二氟-4-氨基苯甲醚,产率84.6%,熔点81~82℃。加入NaNO2、浓H2SO4和K I,在5℃重氮化,经Sandm eyer反应碘代合成2,3-二氟-4-碘苯甲醚,产率75.5%,熔点63~64℃。通过熔点、IR1、HNMR、MS和元素分析对产物进行了表征。

Syntheses of 2,3-Difluoro-4-iodoanisole

2,3-Diaminoanisole was diazotized with conc.HCl and NaNO_2 below 5 ℃ and treated with fluoroboric acids(w(HBF_4)=40%)(Schiemann reaction) to give 2,3-difluoro-4-iodoanisole(Ⅰ) in 40.7% yield.Then,the mixture of w(HNO_3)=65%～68% nitric acid,glacial acetic acid and acetic anhydride was dropped slowly to Ⅰ at 50～60 ℃ on water bath to produce 2,3-difluoro-4-nitroanisole(Ⅱ) in 51.9% yield,m.p.124 ℃.Ⅱ was reduced by SnCl_2 and HCl for 12 h to form 2,3-difluoro-4-aminoanisole(Ⅲ) in 84.6% yield,m.p.81～82 ℃.Finally,2,3-difluoro-4-iodoanisole were obtained in 75.5% yield(m.p.63～64 ℃) by diazotization of Ⅲ at 5 ℃ in NaNO_2 and H_2SO_4 and addition of KI(Sandmeyer reaction).The product was characterized by melting point,IR,~1HNMR,MS and elementary analysis.