Manolova, Y. Kurteva, Vanya B. Antonov, Liudmil Marciniak, H. Lochbrunner, S. Crochet, Aurélien Fromm, Katharina M. Kamounah, Fadhil S. Hansen, P. E. 2015-04-01 A series of naphthaldehydes, including a Mannich base, have been investigated by UV-Vis spectroscopy, NMR and theoretical methods to explore their potential tautomerism. In the case of 4-hydroxy-1-naphthaldehyde concentration dependent deprotonation has been detected in methanol and acetonitrile. For 4-hydroxy-3-(piperidin-1-ylmethyl)-1-naphthaldehyde (a Mannich base) an intramolecular proton transfer involving the OH group and the piperidine nitrogen occurs. In acetonitrile the equilibrium is predominantly at the OH-form, whereas in methanol the proton transferred tautomer is the preferred form. In chloroform and toluene, the OH form is completely dominant. Both 4-hydroxy-1-naphthaldehyde and 4-methoxy-1-naphthaldehyde (fixed enol form) show dimerization in the investigated solvents and the crystallographic data, obtained for the latter, confirm the existence of a cyclic dimer. application/pdf https://folia.unifr.ch/global/documents/304288 https://folia.unifr.ch/documents/304288/files/fro_hnp.pdf https://folia.unifr.ch/documents/304288/files/fro_hnp_sm.pdf https://folia.unifr.ch/documents/304288/files/fro_hnp_sm.txt eng info:eu-repo/semantics/altIdentifier/doi/10.1039/C5CP00870K info:eu-repo/semantics/openAccess License undefined Physical Chemistry Chemical Physics. - 2015, vol. 17, no. 15, p. 10238–10249 info:eu-repo/classification/udc/54 4-Hydroxy-1-naphthaldehydes: proton transfer or deprotonation http://purl.org/coar/resource_type/c_6501