氨基的保护.doc

经典的伯胺与18冠6可以形成络合物，从而达到选择性SES保护基Sulfonamides are among the moststable amine protecting groups under a wide range ofconditions, but they usually require drastic cleavage conditionswhich are generally not compatible with highlyfunctionalized, sensitive substrates. In addition to the commonTosyl group, other sulfonamides have been developedwith the aim of easy deprotection: nosyl, brosyl, tertbutylsulfonyl(Bus), etc. In the same manner, in 1986Weinreb developed the 2-(trimethylsilyl)ethanesulfonyl (or2-(trimethylsilyl)ethylsulfonyl) group, abbreviated as SES.1-5This sulfonyl protection is removed under mild conditionsusing fluoride ions (eq 1). Indeed, attack of the fluoride ionson the silicon atom leads to a -elimination which releasesthe deprotected amine and volatile products: fluorotrimethylsilane,ethylene, and sulfur dioxide.说明用此法保护对强碱没有问题保护4-aminophennol (1.09 g, 10 mmol) and phthalic anhydride(1.48 g, 10 mmol) were dissolved in glacial acetic acid (20 mL) and refluxed for 1h. A white precipiate of N-substituted phthalinide was separated by filtration after cooling, and washed with 30 mL of water to give the desired compound去保护(0.15 g, 0.4 mmol) was dissolved in 10 mL EtOH, and 10 mL NH2NH2H2O was added, the solution was stirred at room temperature