Analyse en résonance magnétique nucléaire du 1 H et du 13 C de dérivés azuléniques extraits de l' Eriocephalae punctulactus

Two azulene compounds were isolated from the extract of Eriocephalaepunctulactus; their structures were determined unambiguously by n.m.r. as those of 1,4-dimethylazulene and 1,4-dimethyl-7-ethylazulene. These structures were confirmed by 13 C n.m.r. The effects of substitution in the azulene ring on the 13 C n.m.r. spectra were demonstrated using these compounds as well as guaiazulene (l,4-dimethyl-7-isopropylazulene). [Journal translation]