Collect. Czech. Chem. Commun. 1981, 46, 1486-1491

13C NMR spectra of azachalcones

Tibor Liptaja, Vladimír Mlynárikb, Milan Remkoc, Ján Ďurindac and Jozef Hegerc

a Central NMR Laboratory, Slovak Institute of Technology, 880 37 Bratislava
b Czechoslovak Institute of Metrology, 834 22 Bratislava
c Pharmaceutical Faculty, Comenius University, 880 34 Bratislava


13C NMR spectral parameters were obtained for chalcone and fourteen its aza- and diazaanalogues. Relative conformation of the carbonyl group with respect to the double bond was studied using changes in 3J(C(1')-Hα) and PCILO method. PCILO calculations together with experimental results show that with 2'-, 3'-, and 4'-azachalcones the s-cis isomer is the most stable form. Whereas the molecule of 2'-azachalcone is planar or nearly planar, in 3'- and 4'-azachalcones the carbonyl group and the olefinic bond planes make angle of 45°.