Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

• Wang-Yong Yang,
• Samantha A. Marrone,
• Nalisha Minors,
• Diego A. R. Zorio and
• Igor V. Alabugin

Beilstein J. Org. Chem. 2011, 7, 813–823, doi:10.3762/bjoc.7.93

• acetamides. The significant protecting effect of the hydroxyl radical and singlet oxygen scavengers to DNA cleavage was shown only with m-lysine conjugate. All three isomeric lysine conjugates inhibited human melanoma cell growth under photoactivation: The p-conjugate had the lowest CC50 (50% cell

• substituent in different positions (o-, m-, and p-) relative to the alkyne (acetamides in Figure 4). Such variations in the substitution pattern are known to impose significant effects on photochemical reactivity [56][57]. Reactions with cyclohexadiene were used to probe the properties of the triplet excited

• follow the order of the photocycloaddition of their acetamides. Although the m-substituted acetylene was more photoreactive toward 1,4-CHD, the corresponding conjugate 6 produced less DNA cleavage than conjugate 1. This suggests that either the difference in DNA binding overshadows the intrinsic