Synthesis And Characterization Of Three New Methyl Dehydroabietate Derivatives And Studies Of Two New Synthetic Methods

Dehydroabietic acid is one of important renewable resource and a natural chiral compound with three chiral carbon atoms and a reactive carboxy group. It is a readily available hydrophenanthrene derivative which offers promise of becoming a useful starting material for the synthesis of industrially or physiologically important products, by the introduction of suitable substituents into the aromatic ring and by alteration of the carboxyl group.In the first chapter, starting from dehydroabietic acid which was purified disproportionated rosin, two important intermedias, methyl 12-bromo-13-nitro-7-oxo dehydrodeisopropylabietate and methyl 12-bromo-13-nitro-dehydrodeisopropylabietate were synthesized through methylation, bromination, nitration. Then treatment of them with four kinds of arylboronic acids resulted in a series of 12-aryl substituted-13-amino-7-oxo-dehydrodeisopropylabietates in moderate yields in the presence of 3 mol % Pd(OAc)2 and 3 equiv of K₂CO₃, in DMF/H₂O at 150 oC. In addition, we have found that nitro reduction reaction and Suzuki cross-coupling reaction were simultaneously occurred without affecting the other reducible ester and carbonyl groups. all of the products'maximal excitation wavelengths and emission wavelengths are red-shifted with fluorescentλex/λem of 394-466nm / 473-541nm compared to dehydroabietic acid and their excitation wavelengths met with our demand of a chiral fluorescence derivatization reagent.In the second chapter, we reported the discovery of an effective Pd(OAc)2/Dabco/DMF/H₂O catalytic system for Suzuki cross-coupling reaction with simultaneous reduction of the nitro- to amino-group. This method allows the preparation of aryl substituted aniline, especially polycyclic series, directly from the corresponding nitro-substituted aryl halides and arylboronic acids. The reaction was catalyzed by a combination of Pd(OAc)₂ (3 mol %) and Dabco (triethylenediamine) (6 mol %) at 150 oC under atmospheric pressure in the presence of K2CO3 (3 equiv) in DMF/H₂O (5/1). Unfortunately, at the moment, we can not offer a definitive reasonable explanation for the process of the reaction. Further efforts to better understand the reaction mechanism are currently underway in our laboratory.In the third chapter, By reaction of methyl 12-(4-biphenyl)-13-amino-7-oxo- dehydrodeisopropylabietic acid with Vilsmeier-Haack reagents under stronger reaction conditions a new compound of rosin-based thiolactone has been synthesized and characterized by IR, NMR and single-crystal X-ray diffraction. Furthermore, we investigated the mechanism of the reaction. Vilsmeier reagents generated from amides and acyl halides have been found to be versatile in the organic synthesis, However, there are no published data about using Vilsmeier-Haack reagents for the synthesis of thiolactone. Thus it not only provided a simple and efficient method for synthesis of thiolactone but also extended the use of Vilsmeier-Haack reagents.In the forth chapter, a kind of rosin-based benzimidazole was synthesized using a simple and efficient procedure from methyl 12-bromo-13,14-diamino-dehydrodeisopropylabietate, which obtained by reduction of methyl 12-bromo-13,14-dinitro-dehydrodeisopropylabietate employing Pt/C as the catalyst, and salicyladehyde in 1,4-dioxane. Then treatment of it with Zn(OAc)2.2H₂O, Co(OAc)2.4H₂O resulted in two complexes. The ligand and the Zn(II) complexes display photoluminescent properties in ca 470nm, 427nm in the solution at room temperature.In summary, 10 new compounds were synthesized and characterized by IR, NMR and single-crystal X-ray diffraction. We have developed a new way of synthesis of thiolactones by Vilsmeier reagent and a new catalytic system under which Suzuki cross-coupling and nitro reduction reaction were simultaneously occurred even at common pressure and without hydrogen.