Reactions of guaiazulene with 2-furaldehyde, thiophene-2-carbaldehyde and pyrrole-2-carbaldehyde in methanol in the presence of hexafluorophosphoric acid: comparative studies on molecular structures and spectroscopic, chemical and electrochemical properti

Reactions of guaiazulene (1) with heteroaromatic-carbaldehydes [i.e., 2-furaldehyde (2), thiophene-2-carbaldehyde (3) and pyrrole-2-carbaldehyde (4)] in methanol in the presence of hexafluorophosphoric acid at 25 °C for 30 min under aerobic conditions give (2-furyl)(3-guaiazulenyl)methylium hexafluorophosphate (5), (3-guaiazulenyl)(2-thienyl)methylium hexafluorophosphate (6) and (3-guaiazulenyl)(2-pyrrolyl)methylium hexafluorophosphate (7), respectively, in 93, 98 and 85% yields. Comparative studies on the molecular structures as well as the spectroscopic, chemical and electrochemical properties of the methylium hexafluorophosphates 5–7 stabilized by 3-guaiazulenyl and 2-furyl (or 2-thienyl or 2-pyrrolyl) groups are reported.

Reactions of guaiazulene (1) with heteroaromatic-carbaldehydes [i.e., 2-furaldehyde (2), thiophene-2-carbaldehyde (3) and pyrrole-2-carbaldehyde (4)] in methanol in the presence of hexafluorophosphoric acid at 25 °C for 30 min under aerobic conditions give the corresponding methylium hexafluorophosphates 5, 6 and 7, respectively, in 93, 98 and 85% isolated yields. The title studies are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide