Naslov
On the Photochemical Dimerization of Some 5-Substituted 2-Styryl-4-pyrones. The Effect of 5-Hydroxy-/5-Methoxy- Substitution

Autori
Stiplošek, Zdenka ; Šindler-Kulyk, Marija ; Jakopčić, Krešimir ; Višnjevac, Aleksandar ; Kojić-Prodić, Biserka

Izvornik
Journal of Heterocyclic Chemistry (0022-152X) 39 (2002), 1; 37-44

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
dimerization; photochemical; 4-pyrone; benzo[f]chromone; styrylpyrone; photocycloaddition; photodehydrocyclization; substituent effect

Sažetak
Irradiation of styryl-4-pyrones 1a-1d or 2a-2e (6-9x10-3 M, methanol solution) with filtered (RAYONET photochemical reactor, 300 nm) or unfiltered uv-light (high-pressure mercury arc lamp) under aerobic conditions led mainly to dimeric products. Parent 5-hydroxy-substituted compounds 1a-1d yielded exclusively "half-cage" dimers 3a-d characteristic for 4-pyrone dimerization. 5-Methoxy-analogues 2a-2e behave like typical stilbene structures and the mixtures of tetrasubstituted cyclobutanes 4 and 5 accompanied with minor amount of phenantrene-like compound 6 were the only isolable products of the irradiation. The structure elucidation of products is based on spectral data obtained from MS, IR, 1H NMR and 13C NMR spectra applying COSY, APT, HETCOR, HMBC and NOESY techniques.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA