Tungstate Sulfuric Acid (TSA) / NaNO_2 as a Novel Heterogeneous System for the N-Nitrosation of Secondary Amines under Mild Conditions

摘要

Nitrosation chemistry has been introduced as an active area for organic and biological chemists.Their strong mutagenic and carcinogenic properties of N-nitrosamines have caused considerable attraction in this view.Also they have been used as pesticides,lubricant and antioxidants.N-Nitrosamines have key role in preparation of various N,N-bonded functionalities and their easy lithiation followed by denitrosative electrophilic reaction which can be applied for the electrophilic substitution of secondary amines at the a-position.In situ generated HNO_2 from sodium nitrite and inorganic acids in water or water/alcohol mixture solvent,is the most general reagent for nitrosation.Some other nitrosating agents,such as fermy's salt,N-haloamides/ NaNO_2 under phase-transfer conditions,nitrogen tetroxide,oxyhyponitrite and oxalic acide have been reported.