一步法合成维生素A棕榈酸酯

一步法合成维生素A棕榈酸酯,以维生素A醇为起始原料,利用催化剂量的脱水剂与酰化反应催化剂等方式,可以得到高纯的产物。此法摩尔收率达91％以上,全反式达到96％以上,生物效价达170万单位以上,与酶催化法及其它化学法合成维生素A棕榈酸酯比,它有收率高,生产周期短、投资少、环保节能等优点。     

离子液体催化合成维A酸维E酯

以维A酸和维生素E为原料,以吡咯烷酮硫酸氢盐离子液体为溶剂和催化剂,合成了维A酸维E酯。考察了反应条件对产品收率的影响,确定了最佳反应条件,为工业化合成维A酸维E酯奠定理论基础,同时对离子液体催化维生素的酯化这类反应提供一定的实验依据。     

由蒈烯-[2]合成拟除虫菊酸的新方法

近年来关于利用天然产物合成具有光学活性的除虫菊酸的方法已有很多报导。M、Matsui等发表了以天然产物( )蒈烯-[3]为原料,经过八步反应,合成了[ ]-反式菊酸。但是,这种合成方法不但步骤太多,工艺复杂,而且其总收率很低。1974年R.Sobti提出了改进方法,经六步反应,即合成了( )-反式菊酸,但总的收率也不高。后来经过Y.Khaura的改进,使全部反应的总收率提高到35%。从天然产物( )蒈烯-[3]合成( )-反式菊酸,若要进一步缩短反应步骤,提高收率,那将是相当困难的。V.P.Adriaan提出四步合成拟除虫菊酸,很有价值。     

改性活性炭负载三聚磷酸二氢铝催化合成阿司匹林

以双氧水改性活性炭负载三聚磷酸二氢铝为催化剂合成阿司匹林,采用单因素实验考察反应温度(A)、酐酸比(C)、反应时间(D)、催化剂用量(B)对阿司匹林收率的影响,采用响应面实验获得较佳的工艺条件。结果表明,该催化反应中对阿司匹林收率影响的顺序依次为合成温度、酐酸比、反应时间、催化剂用量。该催化剂较佳的催化反应条件顺序依次为催化剂用量、反应时间、酐酸比、反应温度。反应温度78.6℃,催化剂加入量占总反应物的6.5 wt%,酐酸比3.72∶1,反应时间47 min,收率86.9%。催化剂重复使用5次后,催化效率仍可达83.2%。响应面实验回归拟合模型为:Y=86.04+0.22×A-1.31×B-0.77×C+1.05×D+0.95×A×B+0.27×A×C-0.73×A×D+0.95×B×C-1.48×B×D-0.30×C×D-3.44×A~2-3.00×B~2-5.40×C~2-4.84×D~2。     

3,3′,4,4′-联苯四甲酸二酐的合成工艺

3,3′,4,4′联苯四甲酸二酐是合成全芳香族聚酰亚胺的重要单体.对其合成路线进行了优化:以邻苯二甲酸酐为原料,经溴化、催化脱卤偶联、脱水环化得到高纯度的3,3′,4,4′联苯四甲酸二酐.同时通过对Pd/C的循环利用进行了研究,确定了Pd/C的合理使用方案.各步反应的最佳条件(反应试剂、反应温度、反应时间、摩尔收率)分别为,溴化:水,75℃,4h,78%;脱卤偶联:水,100℃,2h,90.4%;脱水环化:乙酸酐,回流,2h,97%.优化后路线操作简单,各步反应副反应少,收率较高,总收率达68.4%,产品纯度高,金属离子含量符合要求.     

3,3′,4,4′-联苯四甲酸二酐的合成工艺

3,3′,4,4′-联苯四甲酸二酐是合成全芳香族聚酰亚胺的重要单体.对其合成路线进行了优化：以邻苯二甲酸酐为原料，经溴化、催化脱卤偶联、脱水环化得到高纯度的3,3′,4,4′-联苯四甲酸二酐.同时通过对Pd/C的循环利用进行了研究，确定了Pd/C的合理使用方案.各步反应的最佳条件（反应试剂、反应温度、反应时间、摩尔收率）分别为，溴化：水，75 ℃，4 h，78％; 脱卤偶联：水，100 ℃， 2 h，90.4％;脱水环化：乙酸酐，回流， 2 h，97％.优化后路线操作简单，各步反应副反应少，收率较高，总收率达68.4％，产品纯度高，金属离子含量符合要求.     

Improved Process of the Synthesis of Trans-4-aminocyclohexanol

反式对氨基环己醇是合成祛痰药氨溴素的中间体,已报道的合成路线是以对乙酰氨基苯酚为原料,经加氢后,采用结晶法或柱分离法分离顺反对乙酰氨基环己醇,所得到的反式对乙酰氨基环己醇水解后可得到反式对氨基环己醇,总反应收率为27%(相对于对乙酰胺基苯酚的物质的量收率)。利用反式对氨基环己醇可以和丙酮反应生成席夫碱的原理分离顺反异构体,50 g 对乙酰氨基苯酚在170 ℃,9.0 MPa,5 g骨架镍的条件下加氢,产品用40 g的氢氧化钾水解,得到34.8 g顺反混合的对氨基环己醇,该混合物与200 mL丙酮反应,然后经水解,萃取,得到18.7 g反式对氨基环己醇,熔点112～114 ℃,反式对氨基环己醇的总收率45%（相对于对乙酰氨基苯酚的物质的量收率）。     

食用香料反式-3-辛烯-2-醇的合成研究

以正戊醛和丙酮为原料,经缩合、脱水及还原三步反应合成了反式-3-辛烯-2-醇,此工艺路线原料易得,反应条件温和,总收率为57.6%。缩合反应合成中间体4-羟基-2-辛酮的最佳条件为:反应时间6 h,反应温度25°C,碱的浓度4%,丙酮与戊酮的摩尔比4∶1,脱水采用磷酸,副产物少,收率高(85%);还原反应使用LiAlH4,同样副产物少,收率高(96%)。     

反式对氨基环己醇合成新工艺

反式对氨基环己醇是合成祛痰药氨溴素的中间体，已报道的合成路线是以对乙酰氨基苯酚为原料，经加氢后，采用结晶法或柱分离法分离顺反对乙酰氨基环己醇，所得到的反式对乙酰氨基环己醇水解后可得到反式对氨基环己醇，总反应收率为２７％ （相对于对乙酰胺基苯酚的物质的量收率） 。利用反式对氨基环己醇可以和丙酮反应生成席夫碱的原理分离顺反异构体，５０ ｇ对乙酰氨基苯酚在１７０ ℃，９－０ ＭＰａ，５ ｇ 骨架镍的条件下加氢，产品用４０ ｇ 的氢氧化钾水解，得到３４－８ ｇ 顺反混合的对氨基环己醇，该混合物与２００ ｍＬ丙酮反应，然后经水解，萃取，得到１８－７ ｇ反式对氨基环己醇，熔点１１２～１１４ ℃，反式对氨基环己醇的总收率４５％ （ 相对于对乙酰氨基苯酚的物质的量收率）。     

辅酶Q10的合成

以茄尼醇和2，3－二甲氧基－5－甲基－1，4－苯醌为原料合成全反式辅酶Q10。首先以茄尼醇合成全反式侧链四十碳十烯－1－醇，再和2，3－二甲氧基－5－甲基－1，4－苯醌的还原产物在无水氯化锌存在下缩合。缩合反应收率为20％。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.