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Solvent‐directed Regioselective Benzylation of Adenine: Characterization of N9‐benzyladenine and N3‐benzyladenine
Author(s) -
Buyens Dominique M. S.,
Mangondo Paidamwoyo,
Cukrowski Ignacy,
Pilcher Lynne A.
Publication year - 2017
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.2894
Subject(s) - chemistry , regioselectivity , solvent , polar , nuclear magnetic resonance spectroscopy , medicinal chemistry , carbon 13 nmr , stereochemistry , organic chemistry , catalysis , physics , astronomy
The preferred sites for the benzylation of adenine under basic conditions were proven to be the N9 and N3 positions. Formation of the N9‐benzyladenine product is favored in polar aprotic solvents, such as DMSO, whereas the proportion of N3‐benzyladenine formed increases as the proportion of polar protic solvents, such as water, increases. X‐ray crystal structures were obtained for both N9‐benzyladenine and N3‐benzyladenine. 1 H‐ 13 C HMBC NMR spectroscopy revealed diagnostic correlations used to assign the 1 H and 13 C NMR chemical shifts confirming that the solution structures in three different solvents were the same as the isolated crystals. 13 C NMR assignment for N9‐benzyladenine, N3‐benzyladenine, and N7‐benzyladenine was confirmed by computation using ADF.