2-溴-3-甲基-1,4-二甲氧基萘的合成新方法研究

以2-甲基萘醌(2)为原料,经过催化氢化、甲醚化和溴代三步反应,合成了维生素K2的重要中间体2-溴-3-甲基-1,4-二甲氧基萘(1)。(2)催化加氢还原得到2-甲基-1,4-二羟基萘(3)。(3与硫酸二甲酯反应生成2-甲基-1,4-二甲氧基萘(4),甲醚化反应通过正交实验可使产物收率达到95.1%;(4)与溴反应,经单因素实验在较佳的反应工艺条件下得到目标产物(1),收率90.1%。三步反应总收率达到84.6%。     

2-溴-3-甲基-1,4-二甲氧基萘的合成

以2-甲基萘醌为原料,经过催化氢化、甲醚化和溴化3步反应,合成了维生素K2的重要中间体2-溴-3-甲基-1,4-二甲氧基萘(1)。以钯碳为催化剂加氢还原,得到了2-甲基-1,4-二羟基萘(3),收率98.8%;3在碱性条件下用硫酸二甲酯进行甲氧基保护,生成2-甲基-1,4-二甲氧基萘(4),收率95.1%;4与溴反应可以得到1,收率90.1%。3步反应总收率由传统方法的48.7%提高到84.6%。     

β-甲基萘合成2-甲基-1,4-萘醌绿色氧化反应工艺

2-甲基-1,4-萘醌(2-MNQ)是K族维生素的重要中间体,广泛应用于医药、农药、饲料添加剂等领域。本工作以2-甲基萘(2-MN)为原料,(NH₄)₂S₂O₈为引发剂,用30%H₂O₂与冰醋酸在硫酸催化下制备过氧乙酸并滴加至反应液中,氧化合成2-甲基-1,4-萘醌(2-MNQ),通过ICIR,GC-MS,LCMS对其结构进行表征,并验证氧化反应机理及中间产物。考察了催化剂、反应温度、反应时间、氧化剂与引发剂用量对产品2-MNQ收率、转化率的影响,采用HPLC (外标法)测定产品2-MNQ的转化率和收率,得到最佳工艺条件为反应温度65℃、反应时间5 h、n(H₂O₂):n(2-MN)=26:1,此时,2-甲基萘的转化率为99%,产品收率为34%。本工作的创新点是使用原位红外技术验证反应机理和中间过程,即原料2-甲基萘经过氧乙酸氧化,发生环氧化反应生成中间体,之后重排生成2-甲基羟醌,继续氧化生成目标产物2-甲基-...     

绿色合成β-甲基萘醌的研究进展

β-甲基萘醌为维生素K3,是K类维生素的重要中间体,临床上用于防治出血、解痉、镇痛。本文主要叙述了以β-甲基萘为原料,用绿色方法 (过氧化物氧化法、高效催化剂法、离子液体法、间接电氧化法)合成β-甲基萘醌的研究进展,总结了各个方法的优缺点进而提出合理的建议,并探讨了利用绿色化学法制备β-甲基萘醌的发展前景。     

2-甲基萘催化氧化制2-甲基-1,4-萘醌工业放大研究

以2-甲基萘(工业级)和空气中氧为原料,通过不同反应温度和单管空气流量,在工业级单管装置上考察了自制钒系催化剂催化氧化制2-甲基-1,4-萘醌的活性、选择性和稳定性;并利用X粉末衍射仪(XRD)、扫描电镜(SEM)等表征方法对催化剂反应前后形貌和晶相结构进行表征。结果表明,反应温度390℃,单管空气流量4.5 m3/h,甲基萘转化率不低于64%,2-甲基-1,4-萘醌选择性可达35%以上,2-甲基-1,4-萘醌单程质量收率大于24%;催化剂反应前后外观形貌基本一致,物相稳定。工业级单管试验与实验室结果重现性高。     

K系维生素中间体β-甲基萘醌合成的研究进展

综述了K系维生素中间体β—甲基萘醚(2—甲基—1，4—萘醚，维生素K；)的合成方法及其研究进展，并就当前工业生产技术中存在的问题，提出了适宜而合理的发展方向。     

2-甲基-1,4-萘醌的合成研究

以2-甲基萘为原料,通过溴化、甲氧基化反应合成1-甲氧基-2-甲基萘,以酞菁铁为催化剂,双氧水为氧化剂,1-甲氧基-2-甲基萘氧化制得目标产物2-甲基-1,4-萘醌。文中考察了反应温度、催化剂种类及催化剂用量、物料配比对氧化反应的影响,确定了最佳反应条件:冰醋酸做溶剂,酞菁铁5.5%,双氧水与1-甲氧基-2-甲基萘的物质的量比为3∶1,55℃反应4h。在此条件下,2-甲基萘醌的收率为64.7%,纯度为99.0%(HPLC面积归一化法)。产品结构经熔点、~1H-NMR和MS表征。     

手性方酰胺催化迈克尔加成反应合成1,4-萘醌衍生物的研究

以奎宁和方酸二乙酯为主要原料制备了手性方酰胺催化剂1,研究了催化剂1对指甲花醌和β-硝基苯乙烯反应合成1,4-萘醌衍生物的催化性能。催化剂1和衍1,4-萘醌衍生物的结构经~1 HNMR和~(13)CNMR确证,并对反应采用的溶剂、物料比、反应温度、催化剂用量进行了考察,在最佳的反应条件下,1,4-萘醌衍生物的收率为95.24%,对映体选择性(ee值)为61.18%。     

2-甲基-1,4-萘醌的合成方法综述

维生素K₃作为一类抗出血药物，主要应用于医药及饲料添加剂，具有广阔的市场前景。不同于天然维生素K₁和K₂，维生素K₃需要人工合成，其主体形式是2-甲基-1,4-萘醌或者2-甲基-1,4-萘醌与亚硫酸氢钠的加成物，因此2-甲基-1,4-萘醌的合成方法一直备受关注。本文对2-甲基-1,4-萘醌的合成路线进行综述及初步分析，并展望未来合成工艺的改进方向。     

维生素K3的合成研究

利用 2 -甲基 -1,4萘醌和亚硫酸氢钠为原料 ,合成维生素K3,考察了原料物质的量比、温度、时间对反应的影响。对结晶母液进行了重复利用试验。产品收率可达 75 %以上。     

Iron(III)-induced activation of hydrogen peroxide for oxidation of 2-methylnaphthalene in glacial acetic acid

Simple iron(III) salts activate hydrogen peroxide to oxidize 2-methylnaphthalene to 2-methyl-1-naphthol in glacial acetic acid. 2-Methyl-1-naphthol is then oxidized to 2-methyl-1,4-naphthoquinone by hydrogen peroxide without influence of the catalyst. This is in contrast to the previous reports, which excluded the formation of 2-methyl-1-naphthol as an intermediate product in the process of 2-methylnaphthalene oxidation to 2-methyl-1,4-naphthoquinone. The process, however, mimics the microbial conversion of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone. The presence of chloride in the system causes exclusively the formation of 2-methyl-1-chloronaphthalene.     

Naphthoquinones and Anthraquinones from Scent Glands of a Dyspnoid Harvestman, <Emphasis Type="Italic">Paranemastoma quadripunctatum</Emphasis>

Extracts of Paranemastoma quadripunctatum (Opiliones, Dyspnoi, Nemastomatidae) contained seven components, all of which likely originated from the secretion of well-developed prosomal scent glands. The two main components (together accounting for more than 90% of the secretion) were identified as 1,4-naphthoquinone and 6-methyl-1,4-naphthoquinone. The minor components were 1,4-naphthalenediol, two methoxy-naphthoquinones (2-methoxy-1,4-naphthoquinone, and 2-methoxy-6-methyl-1,4-naphthoquinone) and two anthraquinones (2-methyl-9,10-anthraquinone and a dimethyl-9,10-anthraquinone). While some chemical data on scent gland secretions of the other suborders of Opiliones (Cyphophthalmi, palpatorean Eupnoi, and Laniatores) already exist, this is the first report on the scent gland chemistry in the Dyspnoi. Naphthoquinones are known scent gland exudates of Cyphophthalmi and certain Eupnoi, methoxy-naphthoquinones and anthraquinones are new for opilionid scent gland secretions.     

用于舰船防污涂料的环氧甲萘醌微胶囊的性能调控

该文以聚丙烯酸酯为囊壁,环氧甲萘醌为囊芯制备了环氧甲萘醌微胶囊,并将其应用于舰船防污涂料中。采用透射电镜(TEM)和纳米粒度仪对微胶囊形貌进行表征。考察了微胶囊核壳质量比对涂料中环氧甲萘醌渗出量及涂料防污效果的影响。结果表明,制备的环氧甲萘醌微胶囊平均粒径约为323.5 nm。环氧甲萘醌微胶囊的核壳质量比为1∶7时,制备的涂膜中环氧甲萘醌的释放速率最平稳,涂层防污效果最好。该类微胶囊的研究,为获得使用寿命长、毒性小、价格低廉的舰船防污涂料提供了新途径和新思路。     

Electrochemical oxidation of 2-methylnaphthalene-1,4-diacetate

Cyclic-voltammetric measurements show that 2-methylnaphthalene-1,4-diacetate is electrochemically oxidized on glassy-carbon electrode in glacial acetic acid at +1.45V vs SCE. The process is irreversible and diffusion controlled. Preparative controlled-potential electrolysis indicates that 2-methyl-1,4-naphthoquinone is a sole product. The material and current yields of the process are 94 and 99%, respectively.     

Chemical Profiles of Scent Gland Secretions in the Cyphophthalmid Opilionid Harvestmen, <Emphasis Type="Italic">Siro duricorius</Emphasis> and <Emphasis Type="Italic">S. exilis</Emphasis>

Gas chromatographic–mass spectrometric analyses of the scent gland secretions of Siro duricorius and S. exilis (Opiliones, Cyphophthalmi, Sironidae) revealed a set of 24 components, comprising a series of saturated and unsaturated methyl ketones (C11–C15) and four naphthoquinones. Whereas the scent gland secretions of S. duricorius, collected in Austria, and S. exilis from USA were qualitatively nearly indistinguishable (with the exception of acetophenone that was specific to S. duricorius), they distinctly differed in their relative quantitative compositions: major components of the secretion of S. duricorius were 7-tridecen-2-one, tridecan-2-one, undecan-2-one, 1,4-naphthoquinone, 6-methyl-1,4-naphthoquinone (tentatively identified only), and 4-chloro-1,2-naphthoquinone. In contrast, in S. exilis a compound tentatively identified as 6-methyl-4-chloro-1,2-naphthoquinone was present in large amounts (in S. duricorius a trace component), whereas undecan-2-one only occurred in minor quantities. Secretion profiles of juveniles and adults (both sexes) of each species showed high correspondence.This is the first report on the chemistry of scent gland secretions of the opilionid suborder Cyphophthalmi. 4-Chloro-1,2-naphthoquinone was identified as a new exocrine product of arthropods, whereas 1,4-naphthoquinone and the tentatively identified 6-methyl-1,4-naphthoquinone are known constituents of exocrine secretions from one species of palpatorid opilionids, Phalangium opilio. In contrast, all ketones identified were new for opilionid scent glands, although similar ketones are characteristic of scent gland secretions of palpatorid genera Leiobunum and Hadrobunus. With regard to the near-basic position of Cyphophthalmi in currently proposed phylogenetic trees of Opiliones, naphthoquinones and ketones from Siro may represent the condition ancestral to the (derived) naphthoquinone- and ketone-rich secretions in phalangid Palpatores.     

A Bentonitic Clay Assisted Method for the Preparation of 2-(R-Anilino)-1, 4-Naphthoquinones

A new and efficient protocol to prepare 2-(R-anilino)-1,4-naphthoquinones in quantitative yields is presented. This synthesis occurs under mild conditions by reacting the corresponding aniline and 1,4-naphthoquinone in the presence of a bentonitic clay. The role of the clay is explained in terms of a reaction mechanism in which an activated complex is formed by the reaction of 1,4-naphthoquinone with Lewis acid sites of the clay. Based on the chemical composition of the clay, with Fe³⁺ sites, the last step of the mechanism is proposed to involve an oxidation-reduction reaction.