The Journal of Organic Chemistry
Article
The preparation of the hydrazone between NBD hydrazine and 4-
nitrobenzaldehyde was adopted from an analogous literature
procedure.10 A 75 mg portion of NBD hydrazine and 581 mg of 4-
nitrobenzaldehyde (10 equiv) were stirred in 30 mL of methanol at
room temperature overnight. The resulting dark red solid was filtered,
washed with methanol, and dried to afford 121 mg of pure product
(96%). An analytically pure sample was obtained by flash column
chromatography over silica gel eluting with ethyl acetate. Melting
point > 230 °C.
AUTHOR INFORMATION
Corresponding Author
0295.
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Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This work was supported by the National Institutes of Health
(GM068122, GM067201, and GM072705).
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1H NMR (500 MHz, DMF-d7): 8.94 (s, 1H), 8.45 (d, 2H, J = 8.5
Hz), 8.41 (d, 1H, J = 9 Hz), 8.28 (d, 2H, J = 8.5 Hz), 8.24 (d, 1H, J =
9 Hz)
13C NMR: Solubility in common NMR solvents was too poor to
obtain a spectrum; a saturated sample in DMF-d7 showed only solvent
peaks.
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General Screening Procedure. A 590 μL portion of 10:1 PBS
(pH 7.4):DMF was added to a UV−vis cuvette. A 1.2 μL portion of a
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assumed to be zero at the starting point. All experiments were
performed in triplicate and averaged.
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Equations used for second-order kinetic fits can be found in the
Supporting Information. R2 values for fits were, in most cases, greater
than 0.98.
Reactions at Varied pH. The same conditions as above were used,
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sodium phosphates), pH 5.5 (100 mM sodium phosphates), and pH
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Reactions with Varied Concentrations of Catalyst or
Hydrazine. The same conditions as those in the general section
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or 10 mM with all other concentrations kept constant. For reactions
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concentration varied at 9, 27, or 36 μM.
DNA Conjugation. DNA (H2NO-5′-TTT-GTA-TAT-TAT-GCC-
3′) was synthesized DMT-On and cleaved from the solid support
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ASSOCIATED CONTENT
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S
* Supporting Information
Experimental details and further kinetics information supplied
in the Supporting Information file. This material is available
1189
dx.doi.org/10.1021/jo302746p | J. Org. Chem. 2013, 78, 1184−1189