Nitropyrazoles 4. N-Amination under control of the pH of the medium

Article abstract of DOI:10.1007/BF00699933

A preparative method of N-amination of pyrazoles bearing nitro groups and other electron withdrawing substituents in the pyrazole ring with hydroxylamine-O-sulfonic acid involving control of the pH of the medium has been elaborated.A series of previously unknown pyrazoles has been prepared.Basicities (pK_BH+) of 1-aminopyrazole and 1-amino-4-nitropyrazole have been measured and differences between the basicities of the C- and N-amino groups for the pyrazole series have been revealed. - Key words: nitropyrazoles, N-aminopyrazoles, N-amination.