Synthesis and calcium channel modulating effects of isopropyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(thienyl)-5-pyridinecarboxylates

A group of racemic isopropyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(thienyl)-5-pyridinecarboxylates++ + 7a-f were prepared using a modified Hantzsch reaction that involved the condensation of a thienylcarboxaldehyde 4a-f with isopropyl 3-aminocrotonate 5 and nitroacetone 6. In vitro calcium channel antagonist activities were determined using a guinea pig ileum longitudinal smooth muscle (GPILSM) assay. Compounds 7a-f exhibited weaker calcium channel antagonist activity (IC50 = 10(-5) to 10(-7) M range) than the reference drug nifedipine (IC50 = 1.43 x 10(-8) M). The point of attachment of the C-4 thienyl ring system was a determinant of antagonist activity [3-thienyl (7b) > 2-thienyl (7a)]. A 5-substituent in the 2-thienyl moiety influenced antagonist activity where the potency order was 5-bromo-2-thienyl 7f > or = 5-methyl-2-thienyl 7c > 2-thienyl 7a. Although the 5-methyl-2-thienyl 7c and 3-methyl-2-thienyl 7d isomers are equipotent antagonists, the 5-bromo-2-thienyl compound 7f appears to be marginally more active than the 4-bromo-2-thienyl isomer 7e. The 2-thienyl compound 7a, unlike the 3-thienyl isomer 7b, exhibited an agonist effect on GPILSM in the absence of the muscarinic agonist carbachol. Effects of the 2-thienyl 7a and 3-thienyl 7b isomers on the magnitude of calcium current were determined in guinea pig ventricular myocytes with voltage clamp techniques. Results showed that 2-thienyl 7a inhibited calcium current (antagonist) when voltage steps were made from a potential of -40 mV. However, when voltage steps were made from -60 mV, 7a enhanced calcium current (agonist). The 3-thienyl isomer 7b had little, if any, effect on calcium current.     

Synthesis, rotamer orientation, and calcium channel modulation activities of alkyl and 2-phenethyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(3- or 6-substituted-2-pyridyl)-5-pyridinecarboxylates

A group of racemic alkyl and 2-phenethyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(3- or 6-substituted-2-pyridyl)-5-pyridinecarboxylates (13a-q) was prepared using a modified Hantzsch reaction that involved the condensation of a 3- or 6-substituted-2-pyridinecarboxaldehyde (7a-j) with an alkyl or 2-phenethyl 3-aminocrotonate (11a-d) and nitroacetone (12). Nuclear Overhauser (NOE) studies indicated there is a significant rotamer fraction in solution where the pyridyl nitrogen is oriented above the 1,4-dihydropyridine ring, irrespective of whether a substituent is located at the 3- or 6-position. A potential H-bonding interaction between the pyridyl nitrogen free electron pair and the suitably positioned 1,4-dihydropyridine NH moiety may stablize this rotamer orientation. In vitro calcium channel antagonist and agonist activities were determined using guinea pig ileum longitudinal smooth muscle (GPILSM) and guinea pig left atrium (GPLA) assays, respectively. Compounds having an i-Pr ester substituent acted as dual cardioselective calcium channel agonists (GPLA)/smooth muscle-selective calcium channel antagonists (GPILSM), except for the C-4 3-nitro-2-pyridyl compound which exhibited an antagonist effect on both GPLA and GPILSM. In contrast, the compounds with a phenethyl ester group, which exhibited antagonist activity (IC50 = 10(-5)-10(-7) M range) on GPILSM, were devoid of cardiac agonist activity on GPLA. Structure-activity relationships showing the effect of a substituent (Me, CF3, Cl, NO2, Ph) at the 3- or 6-position of a C-4 2-pyridyl moiety and a variety of ester substituents (Me, Et, i-Pr, PhCH2CH2-) upon calcium channel modulation are described. Compounds possessing a 3- or 6-substituted-2-pyridyl moiety, in conjuction with an i-Pr ester substituent, are novel 1,4-dihydropyridine calcium channel modulators that offer a new drug design approach directed to the treatment of congestive heart failure and may also be useful as probes to study the structure-function relationships of calcium channels.     

1-(5-硝基-3-苯并异噻唑)-3-[4-(苯基偶氮)苯基]- 三氮烯的合成及与钴(Ⅱ)的显色反应

合成了新显色剂1-(5-硝基-3-苯并异噻唑)-3-[4-(苯基偶氮)苯基]-三氮烯(NBPT-PAPT),并研究了该试剂在非离子表面活性剂Tween-80存在下与钴的显色反应。在pH10.54的Na2B4O7-NaOH缓冲溶液介质中,钴与该试剂形成摩尔比为1∶2的黄绿色络合物,其表观摩尔吸光系数ε=1.22×105L.mol-1.cm-1,钴在0～240μg/L范围内符合比尔定律。用双峰双波长光度法测定了水样中微量钴,结果满意。     

Synthesis and stability of 3-nitro-2-pyridinesulfenyl chloride (NpysCl)

3-Nitro-2-pyridinesulfenyl chloride (NpysCl) is the starting material for the synthesis of N-, O- and S-Npys-protected amino acids. Two efficient, novel synthetic routes to NpysCl are described. The stability of NpysCl was determined in a variety of solvents, with and without base, to determine the most suitable solvent and base for the synthesis of N-Npys amino acids. The syntheses of Npys-Ala and Boc-Lys(Npys) tert-butylammonium salt are also described.     

4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯的合成及其与钴的显色反应

合成并鉴定了一种新试剂4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯(5-NO2-PADAB),研究了该试剂与钴(Ⅱ)的显色反应,并建立了一个测定钴的光度分析新方法.结果表明,在pH 6.2～8.0范围内,钴(Ⅱ)与试剂形成紫红色络合物.钴络合物形成后即非常稳定,加入强酸酸化,由于质子化作用,络合物的颜色加深,吸收波长红移,在2.9～6.1 mol/L H2SO4介质中,最大吸收波长红移到580 nm,表观摩尔吸光系数为1.34×106 L·mol-1·cm-1.钴浓度在0～0.48 mg/L范围内符合比尔定律.方法已用于矿样中微量钴的测定,结果与火焰原子吸收光谱法测定结果相一致,相对标准偏差为1.68%.     

Synthesis and in vitro microsomal metabolism of 4-ethyl-5-(4-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione and its potential metabolites

Although most triazoline-3-thione derivatives (cyclic thiosemicarbazides) are important compounds possessing some biological and pharmacological activities, no literature was found showing their metabolic reactions with hepatic microsomal preparations. We, therefore, planned to study the in vitro microsomal metabolism of a prototype, 4-ethyl-5-(4-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (A). The substrate (A) and its potential metabolites i.e. the corresponding dealkylation (A1), desulphuration (A2) and S-oxidation (A3) products were synthesized and characterized by spectral methods. The substrate and its potential metabolites were separated by a reverse phase HPLC. A was incubated with rat microsomal preparations fortified with NADPH and extracted into DCM; concentrated under a stream of N2 at 20 degrees C and analyzed by HPLC. The results indicated that A was metabolically inert and failed to produce the corresponding desulphuration (triazole-3-one) and S-oxidation (sulphenic acid) metabolites which would lead to pharmacological and toxicological alterations compared to the parent molecule. However, a small amount of dealkylated product (A1) was observed as a metabolite together with two unidentified metabolites.     

Photolysis of 4-amino-, 4-alkoxy- and 4-Hydroxy-2,3-dimethyl-1-phenyl-3-pyrazolin-5-ones (author''s transl)

Clinical and hemodynamic results have been evaluated 12--24 months after mitral valve replacement with the new Bj?rk-Shiley tilting disc valve prosthesis. After operation, most patients were improved symptomatically and were classified as I-II (N.Y.H.A.). No patient became worse. Hemodynamic status at rest showed significant reduction in pulmonary capillary venous pressure, pulmonary artial pressure and significant increase in cardiac output when compared with the preoperative values, but postoperative hemodynamic abnormalities remained. Exercise produced a rise in pressures in the pulmonary circuit and in cardiac output. The increase in cardiac output was less than expected from the increase in oxygen consumption, with a few exceptions. Apparently, there was no close relationship between the symptomatic improvement and the hemodynamic results. Thus, the present study points to the importance of hemodynamic data in the objective assessment of the results of cardiac surgery.     

Synthesis and Characterization of Some Lanthanide（Ⅲ） Complexes with 4- [N-（2-methoxy benzylinine）formy1]-2, 3-dimethyl-1-phenyl-3-pyazolin-5-one

A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].     

1-（4-硝基苯基）-3-（4，6-二甲基-2-嘧啶）-三氮烯的合成及与镉的显色反应

报道了1-(4-硝基苯基)-3-(4,6-二甲基-2-嘧啶)-三氮烯(NPDMPMT)的合成及其与镉(Ⅱ)的显色反应.在非离子表面活性剂Triton X-100存在下,于pH 11.5的Na2B4O7-NaOH缓冲介质中,镉(Ⅱ)与NPDMPMT形成1:3的橙黄色络合物,在454 nm处有一最大正吸收,在530 nm处有一最大负吸收,建立了以530 nm为参比波长,454 nm为测量波长的双峰双波长分光光度法测定镉(Ⅱ).25 mL溶液中,镉(Ⅱ)量在0～15μg范围内符合比尔定律,其表观摩尔吸光系数为2.41×105L·mol-1·cm-1,方法的检出限为6.69×10-9g/mL.方法用于废水中微量镉的测定,相对标准偏差在2.9%～3.4%之间,测定结果与原子吸收光谱法相符.     

Agonist and antagonist effects of apomorphine enantiomers on 5-HT3 receptors

Human platelets express several sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) isoenzymes: SERCA2b of 100 kDa apparent molecular mass and two distinct enzymes of 97 kDa, one of them identified as being the SERCA3a isoform. The molecular identity of the third enzyme specifically recognized by the PL/IM430 monoclonal antibody has remained elusive. First, the study of the 3'-end part of platelet SERCA3 mRNA, by means of RT-PCR amplification using sets of primers covering the N-3 to N (ultimate) exons of the human SERCA3 sequence, revealed the presence of two distinct mRNA sequences, SERCA3a and a longer variant. Second, this additional sequence was identified as SERCA3b and found to refer to the insertion of a new exon of 73 bp, located at bp 349 from the beginning of the intronic sequence, linking the penultimate (N-1) exon to the last exon (N) of the human SERCA3 gene. Third, a relationship between the expression of this SERCA3b mRNA and the PL/ IM430 recognizable SERCA protein was observed. SERCA3b mRNA was found to be absent in epithelial HeLa cells not recognized by the PL/IM430 antibody and the expression of this SERCA3b RNA species correlated with that of the SERCA protein recognized by PL/IM430 which was down-modulated in the platelet precursor megakaryocytic CHRF 288-11 cell line as well as upon in vitro lymphocyte activation. Taken together, these results strongly support the notion of the presence of the SERCA3b protein in human cells by showing SERCA3b mRNA in platelets and the fact that the protein corresponding to this mRNA species is very likely the 97 kDa protein recognized by the PL/IM430 antibody.     

1-(6-硝基-2-苯并噻唑)-3-(5-溴-8-喹啉)-三氮烯的合成及其与镍的显色反应

报道了新试剂1-(6-硝基-2-苯并噻唑)-3-(5-溴-8-喹啉)-三氮烯(NBTBQT)的合成、纯化、结构鉴定及性质,并研究了其与镍的显色反应.在pH 9.5的硼砂-氢氧化钠缓冲介质中,在表面活性剂CTMAB存在下,试剂与镍形成2:1蓝色络合物,络合物最大吸收波长位于633 nm,表观摩尔吸光系数为2.16×105 L·mol-1·cm-1,镍的质量浓度在9～240μg/L范围内符合比尔定律,检出限为2.70×10-9g/mL.方法应用于铝合金中镍的测定,相对标准偏差在1.2%～1.7%之间,测定结果与认定值相符.     

Potent inactivator of alpha-chymotrypsin: 2,2-dimethyl-3-(N-4-cyanobenzoyl)amino-5-phenyl pentanoic anhydride

We synthesized a novel potent alpha-chymotrypsin inactivator, 2,2-dimethyl-3-(N-4-cyanobenzoyl) amino-5-phenyl pentanoic anhydride, which fulfilled the criteria of a mechanism-based inactivator: first-order kinetics, irreversibility, saturation kinetics and substrate protection. The inactivation rate constant (kinact) and the enzyme-inhibitor dissociation constant (KI) were calculated to be 0.017s-1 and 0.071 microM, respectively (kinact/KI = 242,000 M-1s-1). These kinetic parameters indicate that this compound is one of the most powerful alpha-chymotrypsin inactivators ever reported. The average number of alpha-chymotrypsin turnovers per inactivation (partition ratio) was calculated to be 1, which indicates that it is a stoichiometrically ideal inactivator of alpha-chymotrypsin. We compared the IC50 values of this compound with those of several chymotrypsin-like serine proteinases (bovine alpha-chymotrypsin, recombinant human chymase and human neutrophil cathepsin G) and a metallo proteinase, rabbit angiotensin converting enzyme (ACE). Our compound, 2,2-dimethyl-3-(N-4-cyanobenzoyl) amino-5-phenyl pentanoic anhydride, inhibited bovine alpha-chymotrypsin potently (IC50 = 1.0 (+/- 0.2) x 10(-9) M) as well as other chymotrypsin-like serine proteinase; recombinant human chymase (IC50 = 7.0 (+/- 1.0) x 10(-8) M) and human neutrophil cathepsin G (IC50 = 1.8 (+/- 0.2) x 10(-7) M). However, rabbit ACE was not inhibited by this compound (IC50 > 1 x 10(-4) M).     

1-(4-硝基苯基)-3-(5,6-二甲基-1,2,4三氮唑)-三氮烯的合成及与汞的显色反应

报道了1-(4-硝基苯基)-3-(5,6-二甲基-1,2,4三氮唑)-三氮烯(NPDMTT)的合成、结构表征及其与汞的显色反应.在Trition X-100表面活性剂和pH 11.0的Na2B4O7-NaOH缓冲溶液中,该试剂与汞形成3:1的浅黄色络合物,络合物的最大负吸收峰位于530nm处,表观摩尔吸光系数为1.34×105L·mol-1·cm-1.Hg2 的浓度在0～36μg/L范围内符合比尔定律,相关系数r=0.999 8.用拟定方法测定工业废水中的汞,RSD≤1.2%,加标回收率为98.8%～101.5%.     

Pharmacokinetics of 1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1- piperazinyl)-1,4-dihydro-4-oxoquinolone-3-carboxylic acid hydrochloride (DW-116), a new quinolone antibiotic in rats

The objectives of this study were to characterize the pharmacokinetics of 1-5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1- piperazinyl)-1,4-dihydro-4-oxoquinolone-3-carboxylic acid hydrochloride (DW-116), a newly developed quinolone antibiotic, and to compare these kinetics with those of ciprofloxacin and rufloxacin, representative quinolone antibiotics, in rats. Rats were subjected to surgery involving catheterization of the femoral vein and artery. DW-116 (4, 20, or 200 mg/kg), ciprofloxacin (20 mg/kg), or rufloxacin (20 mg/kg) was administered either intravenously (iv) or orally. Blood samples were collected at various times and subjected to an HPLC assay for the quinolones. Temporal profiles of plasma concentration after iv administrations of DW-116 at doses of 4, 20, and 200 mg/kg exhibited an apparent multiexponential decline. In the three doses examined, systemic clearance and steady-state volume of distribution of DW-116, calculated by model-independent methods, were in the range 0.17 approximately 0.23 L/h/kg and 2.90 approximately 4.44 L/kg, respectively. When DW-116 was given orally at doses of 4, 20, or 200 mg/kg, the AUC values were nearly identical to those following iv administration, indicating an almost complete absorption (i.e., the percent bioavailability was 90.0 for 4 mg/kg, 99.0 for 20 mg/kg, and 98.3 for 200 mg/kg) in the dose range examined. The absorption of DW-116 appears to be extremely rapid because the mean residence time calculated from the oral administration data was not significantly different from that for the iv administration. At a dose of 20 mg/kg, the mean residence time for iv administered ciprofloxacin and rufloxacin was smaller than that of DW-116, indicating that DW-116 remains in the body longer than the other quinolones. Absolute percent bioavailabilities of ciprofloxacin (69.9%) and rufloxacin (84.9%) were smaller than that obtained for DW-116 (99.0%). Because it has been reported that the in vivo antibacterial activity of DW-116 is comparable or superior to that of rufloxacin and ciprofloxacin, despite the fact that the in vitro activity is significantly lower, the pharmacokinetics of this antibiotic may be responsible, at least in part, for the enhanced in vivo antibacterial activity of DW-116.     

Synthesis and pharmacological activities of ethyl 5-cyano-1,6-dihydro-6-oxo-2-(2,3,4-pyridyl)-3-pyridinecarboxylates and derivatives

The synthesis of ethyl esters of 5-cyano-1,6-dihydro-6-oxo-3-pyridinecarboxylic acids carrying as 2-substituent the 2-,3- or 4-pyridyl group is described. By alkaline hydrolysis followed by acidification, these esters gave the corresponding carboxylic acids, which were decarboxylated to 1,2-dihydro-2-oxo-6-(2,3,4-pyridyl)-3-pyridinecarbonitriles. As milrinone analogues, the above compounds were tested on contractile activity and frequency rate of spontaneously beating atria from reserpine-treated guinea-pigs. Ethyl 5-cyano-1,6-dihydro-6-oxo-2-(2-pyridyl)-3-pyridinecarboxylate showed an appreciable positive inotropic activity, although inferior to that of milrinone; moreover, some other compounds bearing the above 2-substitution pattern showed interesting antiinflammatory, analgesic and hypotensive activity.     

Inhibition of klenow fragment (exo-) catalyzed DNA polymerization by (5R)-5,6-dihydro-5-hydroxythymidine and structural analogue 5,6-dihydro-5-methylthymidine

Oligonucleotides containing 5R-5,6-dihydro-5-hydroxythymidine (5R-3) and structural analogue 5,6-dihydro-5-methylthymidine (9) at defined sites were chemically synthesized via a method that obviates the use of NH4OH. Oligonucleotides prepared by this method were used to examine the effects of 5R-3 and 9 on the fidelity of Klenow (exo-) in vitro. The presence of lesions 5R-3 and 9 in DNA templates was shown to inhibit polymerization of primers hybridized to these templates. Inhibition was observed for both translesional synthesis and extension one nucleotide past the lesion, with the latter being more pronounced. The fidelity of Klenow (exo-) was reduced only slightly when utilizing substrates containing either dihyropyrimidine nucleotide. These results provide the first experimental verification of computational studies carried out on the effects of 3 on DNA templates, and are consistent with a structural model in which the C5-methyl group of 5R-3 adopts a pseudoaxial orientation resulting in a disruption in base stacking.     

Functional characteristics of a series of N4-substituted 1-(2,3-dihydro-1,4-benzodioxin-5-yl)piperazines as 5-HT1A receptor ligands. Structure-activity relationships

The agonistic/antagonistic profile of a series of 10 N4-substituted 1-(2,3-dihydro-1,4-benzodioxin-5-yl)piperazines is evaluated in the in vitro adenylyl cyclase assay. The profile is severely affected by the characteristics of the N4-substituents ranging from full agonism (benzamidoethyl derivative 1), mixed agonism/antagonism (phthalimidobutyl derivative 7) to predominantly antagonism (saccharinbutyl derivate 9). A novel full antagonist 10, as potent as WAY 100635, is obtained by substitution of Cl at C-7 of the benzodioxinyl moiety in 9.     

N-N''''-二安替吡啉对苯二甲酰胺的合成与表征

首次报道了N-N′-二安替比林对苯二甲酰胺的合成方法,并考察了它在几种常见溶剂中的溶解行为,通过元素分析、IR、UV对其组成和结构进行了确认和表征.