A Study of Essentially Free Carbocations Derived via Diazonium and Oxo Diazonium Ions in the Liquid Phase

Abstract

Nitrogen-and nitrous oxide-separated ion pairs containing 4-substituted benzyl cations and carboxylate or tosylate anions were prepared by thermolysis of N-nitroso-and N-nitroamides, acidification of phenyldiazomethane, and nitrosation of N-benzyl-O-benzoylhydroxylamine. The cations were generated in benzene/toluene and benzene/anisole mixtures and were found to partition between the counterion and the solvent and between the aromatic cosolvent and benzene. A familial relationship among the methods was observed. As the cation became more reactive, the yield of solvent-derived products (SDPs) rose and the ratio of rate constants for its reaction with toluene versus benzene, k T /k B , fell. The yield of SDP also rose as the temperature was decreased and as N 2 was replaced by N 2 O; however, k T /k B remained unchanged. Inert diluents had no effect on k T /k B but decreased hydrocarbon yield by 40% on 2-fold dilution. In the presence of reactive diluents that are converted into secondary alkylating agents, both the % hydrocarbon and k T /k B rose. These results are interpreted in terms of the intermediacy of inert-molecule-separated ion pairs (IMSIPs) in deamination. The cation reacted with benzoates and tosylates not only at the oxygens but also at the ipso carbon; subsequent decarboxylation and desulfonylation, respectively, led to diphenylmethanes. The ester/SDP ratio is introduced as a new measure of carbocation reactivity.

Benzo-1,2,3,4-tetrazine 1,3-Dioxides: Synthesis and NMR Study

“…Not much is known about oxodiazonium ions. These ions, generated from aliphatic O ‐acetylated N ‐nitroamines or O ‐acetyl‐ N ‐nitrosohydroxylamines, were proposed by E. White as intermediates as early as the 1960s,17 but their only reaction was the elimination of N 2 O with the formation of alkyl cations. Oxodiazonium ions bearing aromatic substituent should be more stable.…”

Facile benzylation of aromatics in ionic liquid solvents promoted by TfOH, Sc(OTf)3, and Yb(OTf)3·xH2O; New life for a classic transformation

“…The benzylated products obtained in this study were all known compounds and their physical and analytical data had previously been reported. [16][17][18][19][20][21] Diphenylmethane. MS: 167 (100, M21 + ), 152 (30), 115 (10), 91 (20), 65 (15), 51 (20).…”

Evaluation of Nitrosamide Formation in the Cytochrome P450-Mediated Metabolism of Tobacco-Specific Nitrosamines

“…Nitrosamides are recognized as direct-acting carcinogens with common half-lives being on the scale of minutes . Extensive research shows that their stability and reactivity is dependent on temperature, steric and electronic factors, and solvent composition. − In nucleophilic environments, the major products are the corresponding carboxylic acid derivatives and the diazonium species discussed earlier (Scheme ). Thus, if released into a cell, nitrosamides should not only have better stability for traversing the hydrolytic environment of the cytosol but also the ability to alkylate DNA.…”