头孢地嗪钠的合成研究

研究第三代头孢菌素头孢地嗪钠的适合工业化生产的制备工艺，即7-氨基头孢烷酸(7-ACA)与2-(2-氨基噻唑-4-基)-(顺式)-2-甲氧亚胺乙酰硫代苯并噻唑活性酯(5)在二氯甲烷于5℃反应4h生成头孢噻肟酸(3)。收率90％，3在水-丙酮溶液中碳酸钠存在下与2-巯基-4-甲基．5-噻唑乙酸(4)在55～60℃反应4h生成头孢地嗪酸(2)，收率66．3％，最后2与异辛酸钠丙酮溶液在低温反应成盐得到头孢地嗪钠(1)，收率89．7％。三步反应总收率53．5％。所得产品含量99．5％(HPLC)。     

(6R,7R)-7-[2-呋喃基(甲氧亚氨基)乙酰氨基]-3-羟甲基-8-氧代-5-硫杂-1-氮杂二环[420]辛-2-烯-2-甲酸的合成研究

目的　制备(6R,7R) - 7-[2 -呋喃基(甲氧亚氨基)乙酰氨基] - 3-羟甲基- 8-氧代- 5 -硫杂- 1-氮杂二环[4 2 0]辛- 2 -烯- 2 -甲酸。方法　通过7-氨基头孢烷酸的水解,生成去乙酰基7-氨基头孢烷酸,再与2 - (2 -呋喃基)- 2 -甲氧亚胺基乙酸氯反应进行7位氨基的酰化制备上述医药中间体。结果及结论　适宜的反应条件为:7-氨基头孢烷酸在- 2 5℃水解,与2 - (2 -呋喃基) - 2 -甲氧亚胺基乙酰氯在- 10℃反应,二者的摩尔比为1 0∶1. 15,收率可达80 %。     

国产盐酸头孢甲肟的制备

以3-[[(1-甲基-1H-四唑-5-基)硫]甲基]-7-氨基-头孢烷酸盐酸盐(7-ATCA.HC l)为原料,在C7-NH2位置上用活性酯法与侧链化合物2-(2-氨基-4-噻唑基-2-(Z)-甲氧亚胺基乙酸缩合得到头孢甲肟,然后在水溶液中与盐酸成盐而制得盐酸头孢甲肟。以7-ATCA.HC l为基准,总合成收率在66%以上,产物为高纯度结晶性粉末。     

头孢地嗪钠中间体2-巯基-4-甲基-5-噻唑乙酸的合成研究

对头孢地嗪钠的关键中间体2-巯基-4-甲基-5-噻唑乙酸(1)的合成工艺进行了研究，对关键的氯化反应及环合反应进行了适合工业化生产的改进。将乙酰丙酸甲酯与硫酰氯在四氯化碳中于40℃反应6h，得到3-氯乙酰丙酸甲酯(4)，收率84％；4与二硫氨基甲酸铵在50％丙酮-水中于25℃环合反应4h，得到2-巯基-4-甲基-5-噻唑乙酸甲酯(5)，收率81．6％；5在30％氢氧化钠中于25℃水解2．5h，盐酸酸析，得到化合物1，收率94．1％。三步反应总收率64．5％，较文献收率52．7％有较大提高，产品含量≥99．5％(HPLC)，生产成本大幅降低。此合成路线在中试生产中获得成功。     

头孢克肟合成工艺研究

目的 优化头孢克肟的合成工艺.方法 以7-氨基-3-乙烯基-3-头孢环-4-羧酸(简称7-AVCA)与2-(2-氨基噻唑-4-基)-2-[(Z)-甲氧羰基甲氧亚氨基]乙酸-2-苯骈噻唑硫酯(简称MICA活性酯)为起始原料经缩合、水解反应得到目标产物.结果 目标产物的纯度达到99.5％,二步反应的总收率达90％.结论 该制备过程操作简单,环境污染小,适合工业化大生产.中间体头孢克肟甲酯不需经过烘烤直接用于水解反应,简便高收率地制备头孢克肟.     

盐酸头孢甲肟一锅法合成技术

以3-[[(1-甲基-1H-四唑-5-基)硫]甲基]-7-氨基-头孢烷酸盐(7-ATCA)为原料,在C7的-NH2位置上与AE活性酯发生缩合反应得到头孢甲肟.然后在不分离的情况下直接与盐酸成盐得到盐酸头孢甲肟.本方法简化了生产工艺,可以降低成本,增加经济效益,并减少了"三废"的处理数量.以7-ATCA·HCl为基准,克分子收率可达到66.5%以上,产品符合质量标准.     

盐酸头孢唑兰的合成

目的 研究抗生素盐酸头孢唑兰的合成方法.方法 以7-氨基头孢烷酸(7-ACA)为原料,在三乙胺催化下与(Z)-2-(5-氨基-1,2,4-噻二唑-3-基)-2-甲氧亚氨基硫代乙酸(S-2-苯并噻唑)酯缩合得7β-[(Z)-2-(5-氨基-1,2,4-噻二唑-3-基)-2-甲氧哑氨基乙酰氨基]头孢烷酸,再经六甲基二硅胺烷硅烷化保护,与咪唑并[1,2-b]哒嗪在三甲基碘硅烷(TMSI)催化下进行3-位取代反应,然后经甲醇脱保护,阴离子交换树脂除碘离子,最后与盐酸成盐得盐酸头孢唑兰.结果 目标化合物总收率为15%,结构经MS,IR和1H-NMR确证.结论 用本法合成盐酸头孢唑兰,原料易得,操作简便,易于工业化生产.     

头孢噻呋的合成

头孢噻呋可以7－ACA为原料,先与2－呋喃甲硫羟酸缩合得到7－氨基－3[(2-呋喃基羰基）硫甲基]-3－头孢烯－4－羧酸,再以活性硫酯（5）取代需用三苯甲基保护氨基的2－氨基噻唑－4－羧酸的1H－苯并三唑－1－基活性酯,进行7－位酰胺化反应制得。5为反应剂可缩短反应时间（3h）,简化操作,收率可由34％提高至64．6％。产品质量较好,成本较低,易于工业化生产。     

7-氨基-3-乙烯基头孢烷酸的合成

目的研究7-氨基-3-乙烯基头孢烷酸的合成方法。方法以7-苯乙酰氨基-3-氯甲基头孢烷酸对甲氧苄酯为起始原料，采用化学法和酶解法制得目标化合物，总收率分别达到55．6％和58．5％。结果与结论该工艺原料易得，反应条件温和，收率有所提高，具有工业生产价值。     

头孢尼西钠的合成方法改进

目的:研究头孢尼西钠的合成新工艺。方法:7-氨基头孢烷酸(7-ACA)与5-巯基-1,2,3,4-四氮唑-1-甲基磺酸双钠盐(SMT)在BF3作用下缩合,"一锅法"反应生成7-氨基-3-[甲磺酸基-1-H-四唑-5-基-巯甲基]-3-头孢烯4一羧酸(7-AMT)。7-AMT与D-(-)-甲酰基扁桃酸酰氯在pH 6.5～7.0下酰化,在盐酸作用下去甲酰基成头孢尼西酸,再与N,N-二苄基乙二胺二醋酸盐(DBED)结合生成头孢尼西胺盐(头孢尼西DBED)。胺盐经过强酸性阳离子树脂交换,成盐反应得头孢尼西钠。结果与结论:本工艺反应路线缩短,头孢尼西钠反应总收率提高至74.5%,操作简单,适合工业化生产。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

2-(Acetoxyphenyl)-(Z)-styryl sulfides as cyclooxygenase inhibitors

2-(Acetoxyphenyl)-(Z)-styryl sulfides are described as selective cyclooxygenase-2 (COX-2) inhibitors, useful for treating inflammation and COX-2-mediated disorders including neoplasia. 2-(Acetoxyphenyl)-(Z)-styryl sulfide is claimed to be the most potent COX inhibitor in the series with a COX-2 selectivity ratio of 33. This compound is also claimed to be superior to celecoxib (Celebrex^®, Pfizer) in inhibiting cell growth of colorectal carcinoma cells. In this evaluation, the COX inhibitory activity of this compound is compared to that previously disclosed for diarylheterocycles and 2-(acetoxyphenyl)alkyl sulfides. The validity of the DLD-1 cell line in the growth inhibition studies is questioned based on recent literature reports indicating the lack of COX-2 expression in this cell line.     

Sleep-disordered breathing with chronic opioid use

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. μ-Opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon. Since 2001 there has been an emerging literature that suggests that chronic opioid use is related to central sleep apnoea of both periodic and non-periodic breathing types, and occurs in ～ 30% of these subjects. The clinical significance of these sleep-related abnormalities are unknown. This review addresses the present knowledge of control of ventilation mechanisms during wakefulness and sleep, the effects of opioids on ventilatory control mechanisms, the sleep-disordered breathing found with chronic opioid use and a discussion regarding the future research directions in this area.     

Drug targets for cognitive enhancement in neuropsychiatric disorders

The investigation of novel drug targets for treating cognitive impairments associated with neurological and psychiatric disorders remains a primary focus of study in central nervous system (CNS) research. Many promising new therapies are progressing through preclinical and clinical development, and offer the potential of improved treatment options for neurodegenerative diseases such as Alzheimer's disease (AD) as well as other disorders that have not been particularly well treated to date like the cognitive impairments associated with schizophrenia (CIAS). Among targets under investigation, cholinergic receptors have received much attention with several nicotinic agonists (α7 and α4β2) actively in clinical trials for the treatment of AD, CIAS and attention deficit hyperactivity disorder (ADHD). Both glutamatergic and serotonergic (5-HT) agonists and antagonists have profound effects on neurotransmission and improve cognitive function in preclinical experiments with animals; some of these compounds are now in proof-of-concept studies in humans. Several histamine H3 receptor antagonists are in clinical development not only for cognitive enhancement, but also for the treatment of narcolepsy and cognitive deficits due to sleep deprivation because of their expression in brain sleep centers. Compounds that dampen inhibitory tone (e.g., GABA_A α5 inverse agonists) or elevate excitatory tone (e.g., glycine transporter inhibitors) offer novel approaches for treating diseases such as schizophrenia, AD and Down syndrome. In addition to cell surface receptors, intracellular drug targets such as the phosphodiesterases (PDEs) are known to impact signaling pathways that affect long-term memory formation and working memory. Overall, there is a genuine need to treat cognitive deficits associated with many neuropsychiatric conditions as well as an increasingly aging population.