老年痴呆症药物石杉碱甲类似物研究V.光学活性(-)-1-甲基石杉碱甲的合成

目的：光学活性(-)-1-甲基石杉碱甲的合成及其乙酰胆碱酯酶抑制活性的研究。方法：从光学纯的(5S,9R)-5出发,经Wittig反应和双键异构化得化合物6。用三甲基氯硅烷和碘化钠选择性脱保护得吡啶酮7后,用甲醇钠和碘甲烷选择性N-甲基化得8,经酯水解、Curtius重排和脱保护合成了光学活性1位氮上甲基取代的石杉碱甲类似物11。结果：类似物11的乙酰胆碱酯酶抑制活性低于石杉碱甲。结论：1-甲基能影响类似物11和蛋白活性之间形成氢键的作用,因此降低其抑制活性。     

石杉碱甲类似物的研究Ⅲ．N－甲基吡啶酮石杉碱甲类似物的合成

石杉碱甲（１）是从中草药石杉属植物千层塔（ＬｙｃｏｐｏｄｉｕｍｓｅｒｒａｔｕｍＴｈｕｎｂ．）中分得的一种高效可逆的乙酰胆碱酯酶抑制剂，临床试验证实它对早老性痴呆症有显著疗效。本文报道Ｎ－甲基吡啶酮石杉碱甲类似物２和３的合成。２－甲氧基－５－甲氧羰基－１１－亚甲基－５，９－甲撑环辛－７－烯并吡啶（９）在乙腈中用三甲基氯硅烷和碘化钠选择性脱保护以定量的产率得吡啶酮１０，再用甲醇钠和碘甲烷甲基化得Ｎ－甲基吡啶酮１１，１１经碱性水解，Ｃｕｒｔｉｕｓ重排和氨基的脱保护得Ｎ－甲基吡啶酮石杉碱甲类似物２。通过类似的途径从中间体２－甲氧基－５－甲氧羰基－７－甲基－１１－酮－５，９－甲撑环辛－７－烯并吡啶（１４）合成了类似物３。类似物２和３的乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。     

石杉碱甲类似物的研究II.N-甲基吡啶酮石杉碱甲类似物的合成

石杉碱甲(1)是从中草药石杉属植物千层塔(Lycopodium serratum Thunb.)中分得的一种高效可逆的乙酰胆碱酯酶抑制剂,临床试验证实它对早老性痴呆症有显著疗效。本文报道N-甲基吡啶酮石杉碱甲类似物2和3的合成。2-甲氧基-5-甲氧羰基-11-亚甲基-5,9-甲撑环辛-7-烯并吡啶(9)在乙腈中用三甲基氯硅烷和碘化钠选择性脱保护以定量的产率得吡啶酮10,再用甲醇钠和碘甲烷甲基化得N-甲基吡啶酮11,11经碱性水解,Curtius重排和氨基的脱保护得N-甲基吡啶酮石杉碱甲类似物2。通过类似的途径从中间体2-甲氧基-5-甲氧羰基-7-甲基-11-酮-5,9-甲撑环辛-7-烯并吡啶(14)合成了类似物3。类似物2和3的乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。     

老年痴呆症药物石杉碱甲类似物研究Ⅳ（±）-8，15-二氢-去-11，15-二甲基-8-羟基石杉碱甲的合成

石杉碱甲（１）是从我国草药千层塔中分到的一个可逆性的强效乙酰胆碱酯酶抑制剂，将成为新一代治疗早老性和老年痴呆症的药物．基于乙酰胆碱酯酶的Ｘ－衍射晶体结构及石杉碱甲抑制乙酰胆碱酯酶的作用机制研究结果，设计合成了（±）－８，１５－二氢－去－１１，１５－二甲基－８－羟基石杉碱甲（９ａ，９ｂ）．生物活性试验表明这些类似物抑制酶活性远低于天然石杉碱甲     

老年痴呆症药物石杉碱甲类似物研究Ⅵ.(-)-14-去甲基石杉碱甲的不对称全合成及其乙酰胆碱酯酶抑制活性

目的(-)-14-去甲基石杉碱甲的合成及其抑制乙酰胆碱酯酶活性研究.方法从β-酮酯3与2-亚甲基-1,3-丙二醇双醋酸酯4在手性膦配体钯催化下,对映选择性的形成双环化合物5,双键移位后得到关键中间体6,进而复结晶富集后,得到光学纯6.经Wittig反应,得双键化合物7,酯基水解后,得到相应酸8.经改良的Curtius重排,产生氨基甲酸酯9.除去保护后,得目标化合物2.结果 (-)-14-去甲基石杉碱甲仅是天然(-)-石杉碱甲抑制乙酰胆碱酯酶活性1/8.结论由电鳐乙酰胆碱酯酶与(-)-石杉碱甲复合物X-射线衍射结构分析揭示,14-甲基与酶形成氢键是(-)-石杉碱甲高抑制活性的一个必要基团.     

老年痴呆症药物石杉碱甲的类似物研究Ⅱ(±)-失二碳石杉碱甲类似物的合成

石衫碱甲(1)是从中草药干层塔中提取分离到的一种高效可逆的乙酰胆碱酯酶抑制剂,经临床试验证实对老年痴呆症有显著疗效。本文报道保持石杉碱甲分子基本骨架,失二个甲基类似物7和8的合成。β-酮酯2和丙烯醛发生Michael-Aldol反应得直立键和平伏键的羟基化合物9和10,其相应的甲磺酸酯11和12分别在丙二酸钠和醋酸中130℃回流,直立键甲磺酸酯11发生消去反应得需要的环内双键中间体13,而平伏键甲磺酸酯12则发生SN₂取代反应得直立键醋酸酯14。基于全合成路线,合成了失二碳石杉碱甲类似物7和8,其乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。     

(-)-14-去甲基石杉碱甲的不对称全合成及其乙酰胆碱酯酶抑制活性老年痴呆症药物石杉碱甲类似物研究VI.(-)-14-去甲基石杉碱甲的不对称全合成及其乙酰胆碱酯酶抑制活性

目的(-)-14-去甲基石杉碱甲的合成及其抑制乙酰胆碱酯酶活性研究。方法从β-酮酯3与2-亚甲基-1,3-丙二醇双醋酸酯4在手性膦配体钯催化下,对映选择性的形成双环化合物5,双键移位后得到关键中间体6,进而复结晶富集后,得到光学纯6。经Wittig反应,得双键化合物7,酯基水解后,得到相应酸8。经改良的Curtius重排,产生氨基甲酸酯9。除去保护后,得目标化合物2。结果(-)-14-去甲基石杉碱甲仅是天然(-)-石杉碱甲抑制乙酰胆碱酯酶活性1/8。结论由电鳐乙酰胆碱酯酶与(-)-石杉碱甲复合物X-射线衍射结构分析揭示,14-甲基与酶形成氢键是(-)-石杉碱甲高抑制活性的一个必要基团。     

消旋石杉碱甲的全合成研究

本文详细报道了具有抗乙酰胆碱酯酶(AChE)活性的新型石松类生物碱:消旋石杉碱甲[(±)-Huperzine A]的全合成。采用5-乙氧羰基-6-甲基吡啶酮-2(7)为原料,经7步反应合成重要中间体(14),后者经Michael加成,获三环系化合物(17),再经Wittig反应后,分得相应几何构型的化合物(24),最后经改良的Curtius重排和脱除保护基等反应,获全合成终产物(1),并与天然石杉碱甲的IR,~1HNMR,MS相一致。     

老年痴呆症药物石杉碱甲的类似物研究 Ⅰ 5－取代氨甲基－2（1H）－吡啶酮和5－取代氨基－5，6，7，8－四氢喹诺酮的合成

石杉碱甲（１）是从中草药千层塔中分离的新型石松类生物碱。药理试验表明它是一个可逆性的强效乙酰胆碱酯酶抑制剂。初步临床试验证实它对记忆衰退、重症肌无力和多发梗死痴呆症具有明显的疗效，有可能成为新一代治疗老年痴呆药物。基于计算机分子模拟研究，石杉碱甲分子中的５－氨甲基－２（１Ｈ）－吡啶酮（２）结构可能是其药效部分，因此设计并合成了５－取代氨甲基－２（１Ｈ）－吡啶酮类似物（５）．（８），（１３）和５－取代氨基－５，６，７，８－四氢喹诺酮类似物（１６）．（１７）．生物试验表明，这些石杉碱甲简化结构类似物几无抗乙酰胆碱酯酶活性。     

习水产蛇足石杉中石杉碱甲的含量测定

从蛇足石杉[1]中分离到石杉碱甲(Hup A),为了掌握我省各地产蛇足杉中石杉碱甲的含量情况,本实验用HPLC对习水产蛇足石杉中的石杉碱甲进行了测定.     

从D-甘露糖对映有择合成莽草酸甲酯

利用 D-甘露糖的 C_2,C_3,C_4位的绝对构型和天然(-)-莽草酸的 C_3,C_4,C_5位对应一致的特点,从前者经九步反应合成了光学纯的(-)-莽草酸甲酯(11),由于 C_1位羟基选用了苯甲酰基作保护基,使脱保护和用分子内 Wittig-Horner 反应闭环能一步完成,故比文献报道的对映有择合成莽草酸的路线更为简化。     

Novel synthesis of (S)-1-[5-(benzoylamino)-1,4-dioxo-6-phenylhexyl]-L-proline and analogues: potent angiotensin converting enzyme inhibitors

A new approach was developed for the synthesis of (S)-1-[5-(benzoylamino)-1,4-dioxo-6-phenylhexyl]-L-proline (1) and 23 analogues. The delta-(acylamino)-gamma-keto acid intermediates were obtained by a modified Dakin--West reaction using 3-carbomethoxypropionyl chloride. Acylation of L-proline and recrystallization of the mixture of diastereomers gave the optically pure title compound in three reaction steps. The in vitro angiotensin converting enzyme (ACE) inhibitory activity of 1 was confirmed. Some of the novel analogues (6, 11, 13, and 17) were also found to be potent inhibitors of ACE in vitro with an IC50 of 1.4-8.8 x 10(-9) M (IC50 for captopril = 0.9 x 10(-8) M). In vivo these compounds (6, 11, 17, and 18) were much less active than captopril, especially by the oral route. Against angiotensin I (AI) challenge in normotensive conscious rats, 1 and 6 produced less than 50% inhibition at 30 mg/kg po but 57 to 82% inhibition at 3 mg/kg iv. Inhibition by both routes lasted less than 1 h. In renal hypertensive rats, 1 and 15 of its analogues failed to produce significant blood pressure lowering effects, in contrast to the marked effects of captopril. Near maximum inhibition of AI was achieved by continuous intravenous infusions of 1 and 20, suggesting that limited oral activity may by due to degradation and/or clearance.     

Dehydro keto methylene and keto methylene analogues of substance P. Synthesis and biological activity

The synthesis of dehydro keto methylene and keto methylene analogues of substance P using classical peptide synthesis is described. The following analogues were prepared: [pGlu6,Gly9psi(COCH2)(RS)Leu10]SP6-11 (4) and [pGlu6,-(RS)Phe7 psi(COCH2)(RS)Phe8]SP6-11 (8). The use of an improved deprotection scheme employing Meerwein's reagent (Et3OBF4) made possible the syntheses of the novel dehydro keto methylene analogue [pGlu6,(RS)Phe7 psi-(COCH2)delta(E)Phe8]SP6-11 (26) adn the tetrapeptide analogue [pGlu6,(RS)Phe8 psi(COCH2)Gly9]SP6-9(-OMe) (23). Compound 4 was a weak agonist in provoking contractions of the guinea pig ileum. Compound 26 was a potent inhibitor of SP degradation in rat hypothalamus preparations, with an IC50 value of 1.8 microM.     

Novel thiocyanato complexes with potent cytotoxic and antimicrobial properties

The aim of the present study was to assess the cytotoxic and antimicrobial properties of seven new thiocyanato complexes: Ni(C(9)H(11)N(2)O)(SCN), Cu(C(9)H(11)N(2)O)(SCN), Pd(C(9)H(11)N(2)O)(SCN), Pt(C(9)H(11)N(2) O) (SCN), K[Ti(C(9)H(11)N(2)O)(SCN)(3)], Au(C(9)H(11)N(2)O)(SCN), and K[V(O)(C(9)H(11)N(2)O)(SCN)] (T(1)-T(7), respectively). All the complexes showed toxicity against brine shrimp nauplii (Artemia salina L.). The titanium-based complex, T(5), exhibited potent toxicity, with a lethal concentration 50% (the concentration of test compound that kills 50% of A. salina) value of 1.59 microg mL(-1). These new complexes also exhibited promising antibacterial and antifungal properties. A macrodilution technique was used to estimate the minimum inhibitory concentrations of the seven bioactive complexes. Minimum inhibitory concentrations were found to be 8-64 microg mL(-1) against the tested bacterial species.     

Benzodiazepine receptor binding activity of 8-substituted-9-(3-substituted-benzyl)-6-(dimethylamino)-9H-purines

A series of 8-substituted analogues of 9-(3-aminobenzyl)-6-(dimethylamino)-9H-purine (8) were synthesized and tested for their ability to bind to the benzodiazepine receptor (BZR) in rat brain tissue. The most active compound was the 8-bromo-9-(3-formamidobenzyl) analogue 16 (IC50 = 0.011 microM), which was 1000-fold more active than the parent 9-benzyl-6-(dimethylamino)-9H-purine (1) and nearly as active as diazepam. Although substitution of a m-formamido group and an 8-bromo substituent on 1 imparted potent BZR binding activity, neither 16 nor 11 analogues exhibited significant anxiolytic activity on a modified Geller-Seifter conflict schedule.     

Endothelin ET A- and ET B-receptor-mediated inhibition of noradrenaline release from isolated rat stomach

We examined the effect of endothelin-1, endothelin-3 and sarafotoxin S6c on the release of noradrenaline from gastric sympathetic nerve terminals using an isolated, vascularly perfused rat stomach. The release of noradrenaline evoked by electrical stimulation of the gastric postganglionic sympathetic nerves (at 2.5 Hz for 1 min) was inhibited by endothelin-1 (10(-)(10) - 10(-)(8) M), endothelin-3 (10(-)(9) - 10(-)(8) M) and sarafotoxin S6c (a highly selective agonist of endothelin ET(B) receptors) (10(-)(9) - 10(-)(8) M) in a concentration-dependent manner; the inhibitory potencies were as follows: endothelin-1 > endothelin-3 > sarafotoxin S6c. The inhibitory effect of endothelin-1 (3 x 10(-)(9) M) on noradrenaline release was abolished by BQ-123 (a selective antagonist of endothelin ET(A) receptors) in a dose-dependent manner (10(-)(7) and 10(-)(6) M), but not influenced by BQ-788 (a selective antagonist of endothelin ET(B) receptors) (10(-)(7) and 10(-)(6) M). The endothelin-1-induced inhibition of noradrenaline release was attenuated by pretreatment with pertussis toxin (10 micro g/animal, i.v., 4 days before experiments), but not influenced by indomethacin (3 x 10(-)(6) M). These results indicate that endothelin ET(A) and ET(B) receptors located on the sympathetic nerve terminals play a role in the inhibition of noradrenaline release from the rat stomach: endothelin ET(A) receptor-mediated inhibition is carried out by pertussis toxin-sensitive and indomethacin-insensitive mechanisms.