StatusThe thesis was presented on the 29 August, 2012
Approved by NCAA on the 9 October, 2012
Abstract– 1.52 Mb / in romanian
Research field: Bioorganic chemistry; chemistry of natural and physiologically active compounds. The results of the study have been presented as 3 scientific papers and 14 communications at international conferences and symposia, all in all 17 scientific publications, two of which without coauthors. The thesis consists of the Introduction, List of Abbreviations, State-in-the-Art in the area under study, 2 main Chapters, Conclusions, Bibliography of 206 references, and Summary in three languages, and contains 139 pages, 120 pages of the text body, 111 Figures, 12 Tables.
Aim of the study. Development of original chemo-, regio- and stereoselective methods for the synthesis of tetra- and pentanorlabdanic compounds, theoretical and practical importance. Study of their structure a properties, as well as detection of the reaction mechanisms.
Objectives of the study. The synthesis of new tetra- and pentanorlabdanic compounds, functionalized in the positions C-6, C-7, C-8 and C-9 of the cycle B, which are analoguous to natural compounds, are important and easily available; preparation of tetra- and pentanorlabdanic compounds with dihydropyranic and dihydrofuranic cycles; for amber-like odor properties; examination of bromuration of drim-8(9)-en-7-one and drim-7,9(11)-diene, which are pentanorlabdanic compounds with a high synthetic potential; the synthesis of 7-ketoeuryfuran – a compound with a potential biological activity, a suitable intermediary for the synthesis of higher terpenoids.
Novelty, scientific originality and theoretical significance. Development of new, efficient, original and ecologically friendly pathways for the synthesis of polyfunctionalized tetra- and pentanorlabdanic compounds as well as of dihydropyran compounds from norambreinolide, a derivate of sclareol – a labdanic diterpenoid easily available, extracted from waste products of clary sage (Salvia sclarea L.) after processing so as to get an essential oil. An unique pathway for dimerization of a homodrimanic compound was found.
The solved important scientific problem. The methodological particularities were precised and for the first time original methods of simultaneously α hydroxylation of C-6 and C-9 positions in the cycle B were elaborated with formation of polyfunctional tetranorlabdane derivatives which are important objects for theoretical study. Applying some efficient synthetic methodes a series of new tetranorlabdane compounds with dihydropiranic cycles were obtained. Mentioned methods diversify the syntetic routes and enlarge the range of odouros compounds which poses smell of amber grey. Using a new and original dimerization a dimeric compound method was obtained containing tetranorlabdanic units, which is an interesting object for crystallochemistry and reaction mechanisms studies in fine organic chemistry. The optimal conditions for preparation of drimanic sesquiterpenoids, analogues of diterpenes of fregenedane and isofregenedane structure from accessible drimanic sesquiterpenoids were established.
Practical importance of the study. An original method for synthesis of new tetranorlabdanic compounds, analoguos of natural antibiotics – pereniporins A and B was elaborated, via simultaneous functionalization of carbon atoms C-6 and C-9 with the α-oriented hydroxyl groups. Tetranorlabdanic compounds with dihydropiranic cycles and trisubstituted and exocyclic double bonds or with hydroxi group in C-7, were synthesized - compounds that provide new opportunities for amber-like odor compounds synthesis. From the synthesized compounds, 17 were tested on three species of fungi and two species of bacteria, and 9 of them shown both activities. Waste products were employed as vegetable raw materials with the view of obtaining substances of commercial/practical importance for the economy of our country.