Diazonium chemistry

Sandmeyer: 2,4,5-trichloroaniline with 1) HCl / NaNO2; 2) KI, heat (diazotization/Sandmeyer-type) gives 1,2,4-trichloro-5-iodobenzene (the aryl chloride). 75% yield.

Deamination: cyclohex-3-en-1-amine (a primary amine) with Chem Ber 1963 96 2937; 21%; Org Lett 2015 17 2570 gives 3-cyclohexen-1-ol (the deaminated product), 2-cyclohexen-1-OL (the deaminated product) and bicyclo[3.1.0]hexan-2-ol (the deaminated product).

Aryl azide formation: 4-aminobiphenyl (an aniline) with 1) TsOH / NaNO2; 2) NaN3 gives 4-azido-1,1'-biphenyl (the azide). 97% yield.

Azo coupling: anthranilic acid (an aniline) with 1) HCl / NaNO2; 2) N,N-dimethylaniline gives the azo compound. 64% yield.

Sandmeyer: 8-amino-1-tetralone (an aniline) with 1) HBr / NaNO2; 2) CuBr gives 8-bromo-3,4-dihydro-2H-naphthalen-1-one (the aryl bromide). 95% yield.

Azo coupling: 4-phenyl-1,2,5-oxadiazol-3-amine (an aniline) and mesitylene (an alkylbenzene) with 1) NOBF4; 2) mesitylene, heat gives the azo compound. 90% yield.

Sandmeyer: 3-nitroaniline with 1) HCl, NaNO2; 2) CuCl gives 1-chloro-3-nitrobenzene (the aryl chloride).

Sandmeyer: 2,6-dinitroaniline with 1) NaNO2, N2SO4, AcOH; 2) HCl, Cu2Cl2 gives 1-chloro-2,6-dinitrobenzene (the aryl chloride).

Sandmeyer: p-toluidine (an aniline) with 1) H2SO4, NaNO2; H2O; 2) HBr, CuBr gives 4-bromotoluene (the aryl bromide).

Sandmeyer: o-toluidine (an aniline) with 1) HCl (2 equiv.), NaNO2; 2) CuCN gives 2-methylbenzonitrile.

Sandmeyer: 3-nitroaniline with 1) NaNO2, aq. H2SO4; 2) H2SO4, H2O, 160 °C gives 3-nitrophenol.

Sandmeyer: 5-methyl-2,4-dinitroaniline with tBuONO; CuCl2 gives 5-chloro-2,4-dinitrotoluene (the aryl chloride). 92% yield.

Sandmeyer: an aniline with NaNO2; H2SO4 / H2O gives the aryl bromide. 91% yield.