PHOTOCHEMISTRY OF THIOPHENE AND PYRIDINE DERIVATIVES OF BUTADIENE
FOTOKEMIJA TIOFENSKIH I PIRIDINSKIH DERIVATA BUTADIENA
Marko Levačić, Ivana Šagud,1 Irena Škorić1
1Fakultet kemijskog inženjerstva i tehnologije, Sveučilište u Zagrebu, Marulićev trg 19, 10 000 Zagreb, Hrvatska
E-pošta:
Through the years a detailed study of reactivity of stilbene and as continuation butadiene derivatives was conducted in our research group. The energy that is needed for cycloaddition reactions to take place in these conjugated systems can be supplied by photochemical excitation [1, 2] or thermal one [3, 4]. These previously studied butadiene derivatives showed diverse behavior in excited state and gave new polycyclic structures as products. Products with bicyclo[3.2.1]octane skeleton were present in almost all of the irradiation experiments. These structures are widely present in a vast number of biologically active compounds [5] and are hard to obtain in ground state chemistry.
Research was further extended to include new heterocyclic rings into the butadiene structure. Thiophene and pyridine rings were included, and new compounds were successfully synthesized and characterized (picture 1).
Picture 1. 2/3-[4-(2-vinylphenyl)buta-1,3-dienyl]thiophene (1) and 3/4-[4-(2-vinylphenyl)buta-1,3-dienyl]pyridine (2) .
Compounds 1 and 2 were investigated and in excited state gave polycyclic products that were completely characterized. As the yields of the transformations were good and all of the polycyclic products were isolated and characterized the next step was to determine the quantum yields for these cycloaddition reactions.
To determine the quantum yields chemical actinometry was utilized. We used ferrioxalate actinometer as well as potassium iodide actinometer to gain valid reproducible results. In order to conduct these measurements GC-MS and HPLC-MS systems were used.
Reference
[1] I. Kikaš, I. Škorić, M. Kovacs, L. Fodor, Ž. Marinić, K. Molčanov, B. Kojić-Prodić, O. Horvath, J. Org. Chem. 76 (2011) 8641.
[2] D. Vuk, O. Horvath, Ž. Marinić, I. Škorić, J. Mol. Struct. 1107 (2016) 70.
[3] I. Škorić, F. Pavošević, Ž. Marinić, M. Šindler, M. Eckert-Maksić, M. Vazdar, D. Margetić Org. Biomol. Chem. 9 (2011) 6771.
[4] D. Vuk, Ž. Marinić, K. Molčanov, D. Margetić, I. Škorić Tetrahedron 70 (2014) 886.
[5] D. C. Ericsson, L. E. Cuca, M. Sefkow, J. Nat. Prod. 72 (2009) 1245.