Direct amination of 1-substituted 3,5-dinitrobenzenes by 1,1,1-trimethylhydrazinium iodide.

The amination of 1-X-3,5-dinitrobenzenes via the vicarious nucleophilic substitution of hydrogen (VNS) with 1,1,1-trimethylhydrazinium iodide (TMHI) in the presence of t-BuOK or NaOMe in DMSO was studied. It was observed (when X = OMe, OCH 2 CF 3 , OCH 2 CF 2 CF 2 H, OPh) that the amination occurs regioselectively (ratio ofortho/para -isomers is ∼9:1) and with high yield. For X = SPh or SCH 2 Ph, the reaction proceeded with a low yield (less than 20% ), with a ratio of ortho/para-isomers 1:1. For X = PhS0 2 and 2 equiv of TMHI, a double amination occurs and 2,4-diamino-3,5-dinitro-1-phenylsulfonylbenzene predominates in the mixture of isomers. Under the same conditions, 1,3,5-trinitrobenzene undergoes a double amination to yield 2,4-diamino-1,3,5-trinitrobenzene. A proposed mechanism for this reaction is discussed.