A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps： （a） the synthesis of 3-methoxy-4- benzyloxyacetophenone （2...A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps： （a） the synthesis of 3-methoxy-4- benzyloxyacetophenone （2） from acetovanillone （1）, （b） the bromination of compound 2 to produce 3- methoxy-4-benzyloxy-α-bromoacetophenone （3）, and （c） followed by a nucleophilic substitution of compound （3） to obtain 3-methoxy-4-benzyloxy-α-（3-methoxy-4-（1-propenyl）phenol）-acetophenone （4）. The target product was characterized by MS, 1H NMR and 13C NMR spectroscopy. It was found that the trimeric compound synthesized can be used as a preferable lignin model compound because it contains guaiacyl structural unit （3-methoxy-4-hydroxy phenyl propane） linked by α-O-4 and β-O-4 linkages. In addition, under the conditions of microwave irradiation, the reaction time of each step is significantly reduced, and the selectivity of target product is greatly improved. The yields of each step and the overall sequence are 95.31%. 87.3%. 90.6% and 75.4% （95.31%× 87.3% × 90.6%）. respectively.展开更多
In the present work, the highly efficient Erlenmeyer synthesis of azlactones catalyzed by 2- aminopyridine, supported on nano-sphere Si02 is reported. First, the silica nanoparticles were modified with triethoxysilylp...In the present work, the highly efficient Erlenmeyer synthesis of azlactones catalyzed by 2- aminopyridine, supported on nano-sphere Si02 is reported. First, the silica nanoparticles were modified with triethoxysilylpropyl chloride and then 2-aminopyridine was attached to the support via covalent linkages. This new heterogenized catalyst was used for efficient microwave-assisted synthesis of azlactone derivatives with Ac20 as a condensing agent under solvent-free conditions. The present method offers advantages including high yields, short reaction times and simple work-up. Also, the catalyst can be easily recycled and reused several times, which makes this method attractive, economic and environmentally-benign.展开更多
基金financially supported by the National Basic Research Program of China (No. 2012CB215302)National Natural Science Fundation of China (No. 20876064)the Guangdong Provincial Natural Science Fund (No. 9151064101000082)
文摘A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps： （a） the synthesis of 3-methoxy-4- benzyloxyacetophenone （2） from acetovanillone （1）, （b） the bromination of compound 2 to produce 3- methoxy-4-benzyloxy-α-bromoacetophenone （3）, and （c） followed by a nucleophilic substitution of compound （3） to obtain 3-methoxy-4-benzyloxy-α-（3-methoxy-4-（1-propenyl）phenol）-acetophenone （4）. The target product was characterized by MS, 1H NMR and 13C NMR spectroscopy. It was found that the trimeric compound synthesized can be used as a preferable lignin model compound because it contains guaiacyl structural unit （3-methoxy-4-hydroxy phenyl propane） linked by α-O-4 and β-O-4 linkages. In addition, under the conditions of microwave irradiation, the reaction time of each step is significantly reduced, and the selectivity of target product is greatly improved. The yields of each step and the overall sequence are 95.31%. 87.3%. 90.6% and 75.4% （95.31%× 87.3% × 90.6%）. respectively.
基金financial support from the Research Council of Arak University
文摘In the present work, the highly efficient Erlenmeyer synthesis of azlactones catalyzed by 2- aminopyridine, supported on nano-sphere Si02 is reported. First, the silica nanoparticles were modified with triethoxysilylpropyl chloride and then 2-aminopyridine was attached to the support via covalent linkages. This new heterogenized catalyst was used for efficient microwave-assisted synthesis of azlactone derivatives with Ac20 as a condensing agent under solvent-free conditions. The present method offers advantages including high yields, short reaction times and simple work-up. Also, the catalyst can be easily recycled and reused several times, which makes this method attractive, economic and environmentally-benign.
