Identification of the major tautomer for an etheno adduct of 2,6-diaminopurine by determination of the sign of (n)J(H,C).
The major of two solution-state tautomers observed for an etheno product of 2,6-diaminopurine was identified as the tautomer H-1 on the basis of the recognition of the two-bond coupling between the NH proton and C-9a and the three-bond coupling between the NH proton and C-3a. The couplings were distinguished as being over two- or three bonds by determination of the sign of the coupling using two-dimensional heteronuclear NMR, negative in the former case and positive in the latter case. [structure: see text]
Department of Organic Chemistry, Abo Akademi University, FIN-20500 Abo, Finland.
Mattias U
MU
Roslund
Piritta
P
Virta
Karel D
KD
Klika