W. Holzer, G. Eller, S. Schönberger
2008
Citations
0
Influential Citations
10
Citations
Journal
Heterocycles
Abstract
Detailed NMR spectroscopic investigations ( 1 H, 13 C, 15 N) with cinnolin-4-ol (1) reveal this compound to exist exclusively in the cinnolin-4(1H)-one form in deuteriodimethyl sulfoxide solution. This finding is confirmed by comparison of the NMR spectroscopic data of 1 with those of the corresponding 'fixed' O-methyl and N-methyl derivatives, i.e. 4-methoxycinnoline (3) and l-methylcinnolin-4(1H)-one (5). Similarly, cinnoline-4-thiol (4) is present in the thione form in deuteriodimethyl sulfoxide, whereas cinnolin-4-amine (7) exists in the amino form. In addition, in-depth analyses of the NMR spectra of some simple 4-substituted cinnolines are provided.