共查询到20条相似文献,搜索用时 125 毫秒
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设计了一种由 2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)和NaNO2组成的复合催化剂,该催化剂在9,10-二氢蒽氧化脱氢生成蒽的反应中表现出很高的催化活性和选择性. 在120 ℃和1.3 MPa O2下反应 8 h, 9,10-二氢蒽转化率达到99%以上,蒽的选择性为99%. 采用红外光谱和核磁共振方法对催化氧化脱氢的反应历程进行了研究. 结果表明, 9,10-二氢蒽氧气氧化脱氢生成蒽的反应是通过DDQ/DDQH2和NO2/NO两个氧化还原对的电子传递来推动的,以DDQ/NaNO2为催化剂可以有效催化9,10-二氢蒽氧化脱氢生成蒽. 相似文献
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以较好产率合成了3-位具有不同保护基的1,6-缩水-2,4-二-氧-苄基-β-D-吡喃葡萄糖,并对其开环反应以及成苷反应的立体选择性进行了研究. 相似文献
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以(R)-pantolactone为原料,经还原、羟基保护、环合、开环、脱保护、氧化等8步反应,合成了(3S)-2,2-二甲基-3-苄氧基癸酸,总收率为40.0%. 相似文献
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Tetraarylethylenes can be sequentially transformed into 9,10-diarylphenanthrenes and dibenzo[g,p]chrysenes using 1 and 2 equiv of DDQ, respectively, in CH(2)Cl(2) containing methanesulfonic acid, in excellent yields. Efficient access to substituted dibenzochrysenes from tetraarylethylenes establishes the versatility of this procedure over the existing multistep syntheses of dibenzochrysenes. Moreover, the ready regeneration of DDQ from easily recovered reduced DDQ-H(2) continues to advance the use of DDQ/H(+) for the oxidative C-C bond forming reactions. 相似文献
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Jean-Michel Vatèle 《Tetrahedron》2007,63(45):10921-10929
2-(Prenyloxymethyl)benzoates can be prepared from alcohols and readily available 2-(prenyloxymethyl)benzoic acid by standard acylation techniques or by Mitsunobu reaction with inversion of configuration. The POMB group can be cleaved first by oxidative removal of the prenyl group with DDQ followed by lactonization with expulsion of the alcohol catalyzed by Yb(OTf)3. These reaction conditions are compatible with the presence of a large number of common protecting groups. 相似文献
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LI Ling HU Yanna WANG Kailiang WANG Qingmin 《高等学校化学研究》2014,30(4):619-623
A mild synthetic method of a series of phenanthrenes with different substituents on the phenanthrene ring is described.The method involves intramolecular oxidative coupling with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)/trifluoroacetic acid(TFA) as oxidant to produce phenanthrenes in high yields and is fit for large-scale preparation.Furthermore,DDQ can be regenerated by a simple oxidation.The present approach solves a key step for the synthesis of polycyclic structures related to an alkaloid tylophorine. 相似文献
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A facile and direct synthetic method was developed for the construction of vicinal tricarbonyl compounds (VTCs) in moderate to excellent yields (46–92%), by treating the readily available 1,3-dicarbonyl compounds with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The reaction pathway involves the DDQ-mediated oxidative activation of sp3 C–H bond and subsequent coupling to TEMPO to form the key intermediate TEMPO-substrate adduct, which can be further converted to VTC products promoted by DDQ. 相似文献
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Efficient metal-free oxidative aromatization of 2-aryloxycyclohex-2-en-1-ones was achieved by a combination of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and Amberlyst-15. The conditions for oxidative aromatization are mild and applicable for a variety of substrates, and Amberlyst-15 can be successfully recovered and recycled. 相似文献
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The DDQ mediated oxidative cyclisation reactions of a series of dihydronaptho[2,1-b]furans were examined. In the presence of an acid catalyst, the reaction yielded polycyclic ethers and lactones in good to excellent yields. 相似文献
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以DDQ和TBN为催化剂,氧气为氧源,研究了罗素伐他汀母核合成过程中从多取代二氢嘧啶(I)转化为相应的嘧啶中间体(II)的氧化芳构化反应.考察了反应温度,反应溶剂及催化剂用量对氧化芳构化反应的影响.优化实验结果表明,以2%的DDQ及10%TBN为催化剂,氧气为氧源,在甲苯中60℃反应24 h,多取代二氢嘧啶完全转化,获得高选择性的氧化芳构化产物嘧啶中间体(II).在50 mmol规模的氧化芳构化反应的实验中获得了98.8%的分离收率,反应的后处理方便简洁. 相似文献
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The oxidative transformation of the two isomers of the natural lignan hydroxymatairesinol from Norway Spruce (Picea abies) by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), has been studied. Significant differences in the outcome of the reactions were observed when the pure isomers of hydroxymatairesinol were reacted with DDQ under the same conditions. The different stereoelectronic effects in the two isomers as well as their conformational structures seem to determine the site of reaction, which results in different reaction products. Several products were identified by GC-MS and NMR spectroscopy. Oxomatairesinol was obtained in a yield of 25%. 相似文献
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On DDQ oxidation under anhydrous conditions, hydroxy groups located at α or β position to methoxybenzyl ether groups were readily protected by the intramolecular oxidative formation of acid-sensitive methoxybenzylidene acetals, which were further oxidized to alkali-sensitive hydroxy esters in the presence of H2O. 相似文献