阿折地平的合成

二苯甲胺和环氧氯丙烷经亲核取代、闭环、酯化、加成等制得(N-羟基脒基)乙酸-1-二苯甲基氮杂环丁烷-3-基酯(4),4再经Pd/C催化氢化得到脒基乙酸-1-二苯甲基氮杂环丁烷-3-基酯乙酸盐(5).另由间硝基苯甲醛和乙酰乙酸异丙酯在乙酸哌啶催化下反应制得2-(3-硝基亚苄基)乙酰乙酸异丙酯(6).5和6经Michael加成、环合反应制得阿折地平,总收率约40％(以二苯甲胺计).     

氯维地平的合成

3-羟基丙腈和双乙烯酮在三乙胺作用下制得乙酰乙酸(2-氰基乙基)酯(2),再与2,3-二氯苯甲醛和3-氨基巴豆酸甲酯经Hantzsch缩合闭环,接着用硫化钠在常温下选择性水解得4-(2,3-二氯苯基)-1,4-二氢-2,6-二甲基-3,5-吡啶二羧酸单甲酯,最后与正丁酸氯甲酯反应即得抗高血压药氯维地平,总收率约59%(以2计)。     

盐酸马尼地平的合成

以哌嗪为起始原料,经环氧乙烷加成、二苯甲基溴缩合、用双乙烯酮乙酰化得乙酰乙酸2-(4-二苯甲基-1-哌嗪基)乙酯,最后与间硝基苯甲醛和β-氨基巴豆酸甲酯环合制得盐酸马尼地平,总收率28.9%.     

氯维地平的合成

2,3-二氯苯甲醛、乙酰乙酸甲酯和浓氨水经闭环缩合、选择性水解得4-(2,3-二氯苯基)-1,4-二氢-2,6-二甲基-3,5-吡啶二羧酸单甲酯,再与正丁酸氯甲酯反应制得抗高血压药氯维地平,总收率约44%.     

坎地沙坦酯的合成

以3-硝基邻苯二甲酸为起始原料，经酯化、卤代、重排、还原、闭环等反应制得抗高血压新药坎地沙坦酯，优化了中间体的制备工艺，并提出了侧链的新法合成工艺。反应总收率7％。     

法西多曲的合成

参照已知方法制得的2-乙氧羰基-3-(3,4-亚甲二氧基)苯基丙酸钾(6),用KBH_4/ZnCl_2选择性还原得2-羟甲基-3-(3,4-亚甲二氧基)苯基丙酸(7),再经葡辛胺拆分、双氯化得到的(R)-2-氯甲基-3-(3,4-亚甲二氧基)苯丙酰氯(8)与L-丙氨酸苄酯缩合后得N-[(2S)-2-氯甲基-3-(3,4-亚甲二氧基)苯丙酰基]-L-丙氨酸苄酯(9),与硫代乙酸钾反应得法西多曲,总收率约16%(以胡椒醛计)。其中2个中间体(8和9)为未见文献报道的新化合物。     

西尼地平的合成

以双烯酮为原料，分别与乙二醇单甲醚和肉桂醇进行酯化反应制得乙酰乙酸-2-甲氧基乙酯和乙酰乙酸肉桂酯，前者与间硝基苯甲醛缩合生成的2-（3-硝基亚苄基）乙酰乙酸2-甲氧基乙酸和后者的氨化产物3-氨基-2-丁烯酸肉桂酯再进行Hantzsch环化反应制得新型钙拮抗剂西尼地平。方法条件温和，反应总收率68.3%(以肉桂酯计）。     

缬沙坦的合成

N-[(2’-氰基联苯-4-基)甲基]-L-缬氨酸甲酯,与正戊酰氯在甲苯中,以DMAP作催化剂、碳酸钠作缚酸剂进行酰化反应制得N-(1-氧代戊基)-N-[(2’-氰基联苯-4-基)甲基]-L-缬氨酸甲酯,再在相转移催化剂双三甲基硅烷化聚乙二醇400(4)作用下与叠氮钠反应成四唑后,经水解制得抗高血压药缬沙坦,总收率约75%。     

缬沙坦的合成工艺研究

目的研究缬沙坦的新合成方法。方法以N-(三苯基甲基)-5-(4'-溴甲基联苯-2-基)四氮唑为原料,经Kornblum氧化、还原胺化、酰化、去保护基制得N-[2'-(1H-四氮唑)-5-基]-[(1,1'-联苯-4-基)-甲基]-N-戊酰-L-缬氨酸甲酯,后经水解、酸化得缬沙坦。结果与结论目标化合物的结构经1H-NMR谱确证,总收率为37.6%。新方法避免了消旋化,为合成缬沙坦提供了新的思路。     

盐酸贝那普利的合成

以L-苹果酸为手性源,经成酐活化、傅-克反应、常压氢化和酯化反应制得(S)-2-羟基-4-苯基丁酸乙酯(8),8经甲磺酰化活化后经与丙酸钾反应和水解制得构型反转的(R)-2-羟基4-苯基丁酸乙酯(3).3经磺酰化活化后与(3S)-3-氨基-2,3,4,5-四氢-2-氧代-1H-1-苯并氮(革)-1-乙酸叔丁酯(2)反应后水解、成盐制得盐酸贝那普利,总收率约32％.     

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.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

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.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.