Bithiazole moiety

Bis(aminoalkyl)bithiazoles are useful as DNA cleavage agents. Bleomycin contains a 2,4 -bithiazole moiety which plays an important role in the interaction with double stranded DNA during the cleavage reaction. The 2,2 -bis(aminomethyl)-4,4 -bithiazole (70) has been synthesised by the condensation of l,4-dibromobutane-2,3-dione with Boc-glycinethioamide... 

Bleomycin (Blm) is a natural product that is in regular use in combination chemotherapy. The left side of its structure contains a versatile metal-binding domain, probably composed of five labeled nitrogens (Figure 1). The right side includes a bithiazole moiety and a positively charged, variable R group, which can bind to DNA. A well-defined role for the disaccharide unit has yet to be established. 

Further evidence that the pyrimidine is bound in the iron derivatives can be seen in the difference spectra shown in Figure 5. Both of the complexes exhibited a pyrimidine ir-ir electronic transition which was shifted from its original position in bleomycin. This band occurs at 230 nm in the free drugs and shifts to 250 nm in their metalloderivatives. In addition, the iron complexes exhibit a second strong envelope at 300 nm. Since transitions due to two chromophores present in the antibiotics, the n of the pyrimidine and the ir-ir of the bithiazole moiety, overlap at 290 nm, the origin of the band at -300 nm in the difference spectra of the metalloderivatives is difficult to determine. 

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