Formation of N-N and N-C Bond-Cleavage Products in Displacements with N,N-Disubstituted Hydrazines on 1-Halo- or 1,4-Dihaloanthracene-9,10-diones

Article abstract of DOI:10.1021/jo00260a022

The displacements of 1-halo- and 1,4-dihaloanthracene-9,10-diones by N,N-disubstituted hydrazines have been studied.These reactions proceed via N-N bond cleavages of the hydrazine to yield products with the regiospecific incorporation of an N,N-disubstituted amino group.In addition, pyrazoles which arise from intermediates which undergo N-C bond cleavage are also formed.The ratio of the N-N to N-C cleavage products is dependent on the reaction solvent, temperature, structure of the hydrazine, and the nature of the leaving group being displaced from the anthracene-9,10-dione.For example, treatment of 1a with N,N-dimethylhydrazine in pyridine or dimethyl sulfoxide (DMSO) leads to 3a:2c ratios of 6 and 3, respectively.Compound 1e under comparable reaction conditions gives 3a:2c product ratios of 49 and 4, respectively.The dichloro dione 1c with N,N-dimethylhydrazine in pyridine or DMSO leads predominantly to 3b in 76percent and 72percent yields, respectively, with relatively little pyrazole 2d.The more reactive difluoro dione 1h on reaction with N,N-dimethylhydrazine in pyridine leads to N-N bond-cleavage products 3c (48percent) and 3d (40percent).Treatment of 1e with 1-piperidinamine in pyridine yields 3f.The results will be discussed.