Study On The Synthesis Of Coenzyme Q

The application, market demand in the world and methods of preparation, in particular synthesis of coenzyme Q10 were reviewed. It is important to synthesize coenzyme Q10 industrially from a standpoint of economy. In this paper, is presented the important processes of the synthesis of the aromatic ring 6-bromo-2,3-dimethoxy-5-methylhydroquinone-0,0'-dibenzyl ether 6, the preparation of the side-chain and the coupling of aromatic ring 6 and the side-chain in the synthesis of coenzyme Q10 with the way of elongation of the side-chain with 3,4,5-trimethoxy toluene as starting material and self-prepared solanesol as important intermediate.2,3-Dimethoxy-5-methyl-l,4-benzoquinone 2(coenzyme Qo) was prepared from 3,4,5-trimethoxy-toluene 1 using supported heteropolyacid as catalyst, acetic acid as reaction medium, hydrogen peroxide as oxidant. Effect of reaction medium, the amount of catalyst, the amount of acetic acid and hydrogen peroxide, the concentration of hydrogen peroxide on reaction was studied. 40ml acetic acid, 40ml 50% hydrogen peroxide, and 10g supported heteropolyacid catalyst are required for 24g material 1 and the temperature should be 30-3 5 ℃ The product was separated with continuing refluence extraction apparatus. The supported catalyst is free of causing industrial pollution and can be reused. The purity of product can be 94.5% and the yield can be 89.6%. The structure of prepared product has been confirmed by the measured melting point, IR and !H NMR.6-Bromo-2,3-dimethoxy-5-methyl-l,4-hydroquinone 5 was prepared from 2,3-dimethoxy -5-methyl-l,4-benzoquinone 2 with two ways, the one bromination of 2 then reduction, the other reduction of 2 then bromination. Effect of temperature on bromination of 2,3-dimethoxy-5-methyl-l,4-benzoquinone and 2,3- dimethoxy-5-methyl- ,4-hydroquinone was studied. The mechanism of the front reaction is addition and then elimination, while the latter substitution reaction in benzene ring. Reduction of 2,3-dimethoxy-5-methyl-l,4-benzoquinone 2 and 2,3-dimethoxy-5-methyl-6-bromo-l,4-benzoquinone 3 was studied. It has been shown that the latter is more easily reduced than the front. The Pd/C is better than sulfur dioxide and sodium sulfite as reductant. The structure of prepared product was characterized by the measured melt point, IR and 'H NMR.It is showed that the protection of hydroxy groups with benzyl group is better than with methoxy methyl group in the 2,3-dimethoxy-5-methyl-6-bromo-l,4-hydroquinone 5. The benzyl group-protecting product is easily separated from the reaction medium and the yieldis almost 100%. The structure of benzyl group-protecting product was characterized by theABSTRACTmeasured melting point, IR and 'H NMR and the methoxy methyl group-protecting product was characterized by IR and ESI.Trans- l-benzenesulfonyl-2-methyl-4-chloride-2-butene 8 was synthesized with the addition of benzenesulfonyl chloride and isoprene in autoclave with cupric chloride and triethylammonium chloride as catalyst. Effect of temperature, the amount of isoprene and catalyst on reaction was studied. A mechanism for the reaction was elucidated which explains the experimental results better. The structure of prepared product was characterized by the measured melting point, IR and JH NMR and its yield is 75%.Solanesol with purity of 93.4% was isolated from discarded tobacco extracts via saponification, column chromatography, and followed by crystallization. The preferential condition of saponification of discarded tobacco is dissolving it with toluene at 60 癈 and the crude product was obtained in this process with purity of 25% and yield of 75%. The crude product was chromatographed on silica gel using the mixed solvent system of petroleum ether and ethyl acetate(9:l) for elution. Toluene, methanol and ether are cheap and can be reused. The structure of prepared product was confirmed by the measured melting point, IR, 'H NMR, 13C NMR and Dept 135.Solanesol was brominated with phosphorus tribromide as brominating agent, pyridine as catalyst, ethyl ether as reacti...