Phosphates phenolic backbones

The above section already introduced the influence of leaving groups at the benzylic position that eliminate to form and regenerate QM3, and the trend extends beyond adducts formed by the deoxynucleosides as expected. The standard benzylic acetate of QMP4 eliminates completely from the deprotected phenol under neutral aqueous conditions and ambient temperature within approximately 20 h, while an equivalent benzyl bromide eliminates completely within 5 min.48 Benzylic phosphates are also extremely labile, and, if the phosphate backbone of DNA is able to trap QM, the resulting products are likely to be too labile for standard detection.53,54 In contrast, amines and thiols are much less susceptible to elimination from the benzylic position and require forcing conditions to regenerate the parent QM.26,30 The benzylic alcohol derivative also appears stable under almost all thermal conditions and only eliminates routinely to form a QM after photochemical excitation.55... 

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