Kappa-receptor selective binding of opioid ligands with a heterocyclic bicyclo[3.3.1]nonan-9-one structure

Previous pharmacological results have suggested that members of the heterocyclic bicyclo[3.3.1]nonan-9-one-like compounds are potent kappa-opioid receptor specific agonists. One lead molecule of this series. called compound 1 (dimethyl 7-methyl-2,4-di-2-pyridyl-3.7-diazabicyclo[3.3.1]nonan-9-one-1,5-dicarboxylate) exhibited high affinity for [3H]ethylketocyclazocine and [3H]U-69.593 binding sites in guinea pig cerebellar membranes which known to be a good source for kappa1 receptors. It was shown by molecular modelling that heterocyclic bicyclo[3.3.1]nonan-9-ones fit very well with the structure of ketazocine, a prototypic kappa-selective benzomorphan compound; when compared to the arylacetamide structure of U-69.593, a specific kappa1-receptor agonist, a similar geometry was found with a slightly different distribution of the charges. It is postulated, that the essential structural skeleton involved in the opioid activity is an aryl-propyl-amine element distributed along the N7-C6-C5-C4-aryl bonds.     

Geranyl flavonoids from the leaves of Artocarpus altilis

Five geranyl dihydrochalcones, 1-(2,4-dihydroxyphenyl)-3-{4-hydroxy-6,6,9-trimethyl-6a,7,8,10a-tetrahydro-6H-dibenzo[b,d]pyran-5-yl}-1-propanone (2), 1-(2,4-dihydroxyphenyl)-3-[3,4-dihydro-3,8-dihydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (4), 1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methyl-2-(3,4-epoxy-4-methyl-1-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (5), 1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methyl-2-(4-hydroxy-4-methyl-2-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (8), and 2-[6-hydroxy-3,7-dimethylocta-2(E),7-dienyl]-2',3,4,4'-tetrahydroxydihydrochalcone (9), along with four known geranyl flavonoids (1, 3, 6, 7), were isolated from the leaves of Artocarpus altilis. Their structures were established by spectroscopic means and by comparison with the literature values. Compounds 2, 4, and 9 exhibited moderate cytotoxicity against SPC-A-1, SW-480, and SMMC-7721 human cancer cells.     

3-{2-[Bis-(4-fluorophenyl)methoxy]ethyl}-6-substituted-3,6-diazabicyclo[3.1.1]heptanes as novel potent dopamine uptake inhibitors

A series of analogues 2a-i related to 3-{2-[bis-(4-fluorophenyl)methoxy]ethyl}-8-(1H-indol-2-ylmethyl)-3,8-diazabicyclo[3.2.1]octane (1) in which the 3,8-diazabicyclo[3.2.1]octane core was replaced by 3,6-diazabicyclo[3.1.1]heptane ring system has been synthesized and evaluated for their ability to inhibit DA reuptake into striatal nerve endings (synaptosomes). Biological data showed that compound 2a, the closest analogue of lead 1, possessed an increased reuptake inhibition activity over 1 (2a, K(i)=5.5 nM). Replacement of the indole ring with bioisosteric aromatic rings--benzothiophene (2b), benzofurane (2c), or indene (2d)--resulted, with the exception of 2d, in a double digit nanomolar activity. Changing the indenyl moiety of 2d with simplified aryl groups led to compounds 2e-h which displayed a similar or slightly decreased activity with respect to the ground term. Naphthalene derivative (2i) demonstrated a weaker activity than aromatic analogues.     

High yield regioselective monobenzyloxycarbonylation of secondary alcohols in glycopyranoside series

The regioselective monobenzyloxycarbonylation of secondary alcohols in methyl 6-O-(4-methoxytrityl)-alpha-D-manno-, gluco- and galactopyranoside has been achieved in high yields (74-85%) by using benzyl chloroformate in the presence of 4-dimethylaminopyridine and/or 1,4-diazabicyclo[2.2.2]octane.     

Synthesis of 4-deoxy analogues of 2-acetamido-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-xylose and their effects on glycoconjugate biosynthesis

4-Deoxy analogues of 2-acetamido-2-deoxy-D-glucose and 2-acetamido-2-deoxy-D-xylose were synthesized and evaluated as inhibitors of glycoconjugate biosynthesis. Methyl 2-acetamido-2,4-dideoxy-beta-D-xylo-hexopyranoside (11) showed a reduction in [3H]GlcN and [14C]Leu incorporation into hepatocyte cellular glycoconjugates by 89 and 88%, of the control cells, respectively, at 20 mM, whereas the free sugars, 2-acetamido-2,4-dideoxy-alpha,beta-D-xylo-hexopyranoses (15), showed a reduction of [3H]GlcN and [14C]Leu incorporation by 75 and 64%, respectively, at 20 mM. The acetylated analogues of 11 and 15, namely methyl 2-acetamido-3,6-di-O-acetyl-2,4-dideoxy-beta-D-xylo-hexopyranoside and 2-acetamido-1,3,6-tri-O-acetyl-2,4-dideoxy-alpha,beta-D-xylo-hexopyra noses, showed a greater inhibition of [3H]GlcN and [14C]Leu incorporation at 1 mM compared with their non-acetylated counterparts, but were toxic to hepatocytes at concentrations of 10 and 20 mM. Corresponding derivatives of 2-acetamido-2,4-dideoxy-L-threo-pentopyranose showed no biological effect up to 20 mM, suggesting that the C-6 substituent is important for the biological activity.     

Synthesis of C-6 Pyrimidine Acyclic Nucleoside Analogs as Potential Antiviral Agents

Abstract

A number of pyrimidine acyclic nucleosides in which the acyclic moiety is attached to the C-6 position rather than N-1 of the pyrimidine ring have been prepared. This was accomplished via treatment of lithiated 2,4-dimethoxy-5,6-dimethylpyrimidine, or, 2,4-dimethoxy-6-methylpyrirnidine with 1,3-bis-(benzyloxy)-2-propanone, benzyl chloromethyl ether or oxirane, respectively, to give the corresponding key intermediates 6-[3-benzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxy-5-methylpyrimidine (2a), 6-[3-Denzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxypyrimidine(2b), 6-(2-benzyloxyethyl)-2,4-dimethoxy-5-methylpyrimidine (3), and2,4-dunethoxy-6-(3-hydroxypropyl)-5-methylpyrimidine (4a). After acidic hydrolysis, followed by debenzylation with boron trichloride these key intermediates were converted to the target C-6 pyrimidine acyclic derivatives. Compounds 6–8b, 11–13, 15, 16, 20, 22, 26, and 29–32 were evaluated for activity against herpes viruses and human immunodeficiency virus. None of the compounds were active against the viruses nor were they cytotoxic at the highest concentration tested.     

Synthesis of 3,6-diazabicyclo[3.1.1]heptanes as novel ligands for neuronal nicotinic acetylcholine receptors

Alpha series of novel 3,6-diazabicyclo[3.1.1]heptane derivatives 4a-f was synthesized and their affinity and selectivity towards alpha4beta2 and alpha7 nAChR subtypes were evaluated. The results of the current study revealed a number of compounds (4a, 4b and 4c) having a very high affinity for alpha4beta2 (K(i) at alpha4beta2 ranging from 0.023 to 0.056 nM) versus alpha7 nAChR subtypes; among these compounds, the 3-(6-bromopyridin-3-yl)-3,6-diazabicyclo[3.1.1]heptane 4c was found to be the most alpha7alpha4beta2 selective term in receptor binding assays (alpha7alpha4beta2=1295). Moreover, compound 4d also had high affinity for the alpha4beta2 nAChR subtype (K(i)=1.2 nM) with considerably high selectivity (alpha7/alpha4beta2=23300).     

Identification of the corticotropin binding domain of bovine serum albumin by photoaffinity labeling

The interaction of the pituitary hormone corticotropin (ACTH) with bovine serum albumin (BSA) was investigated by photoaffinity labeling with 2-nitro-4-azido-phenylsulfenyl (2,4-NAPS) derivatives of aCTH and [Trp-(SH)9]ACTH. Nearly 30 mol % of tritiated [2,4-NAPS-Trp9]ACTH was covalently bound to BSA at a molar ratio of hormone:BSA of 1.33. The [2,4-NAPS-Trp9] [3H]ACTH-BSA complex was isolated, and the CNBr fragments of the complex were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The radioactivity was predominantly associated with the amino-terminal CNBr fragment corresponding to residues 1-183 in BSA. This result was confirmed by studies of the inhibition of covalent labeling of BSA by photoreactive ACTH. 8-Anilinonaphthalenesulfonic acid which binds to the amino-terminal domain of BSA strongly inhibited the photolabeling of BSA by [2,4-NAPS-Trp9][3H]ACTH. Palmitate and progesterone, known to bind to the carboxy-terminal domains of BSA, did not inhibit the incorporation of [2,4]NAPS-Trp9][3H]ACTH into BSA. The removal of ACTH from the covalent complexes was also investigated. The release of ACTH from the [2,4]NAPSS-Trp9]ACTH--BSA complex by treatment with beta-mercaptoethanol was complete in 6 h, but only 80% of ACTH was released from [2,4]NAPS-Trp9]ACTH--BSA under these conditions.     

厌氧条件下Shewanella oneidensis MR-1对2,4-二硝基甲苯的还原转化

【目的】研究Shewanella oneidensis MR-1厌氧生物转化2,4-二硝基甲苯(2,4-DNT)的能力、转化过程和影响因素。【方法】以乳酸钠为电子供体, 2,4-DNT为电子受体, S. oneidensis MR-1为降解菌, 黄素为胞外电子载体, 设立四个不同的对照体系并监测各体系在转化过程中2,4-DNT及其产物的动态变化。同时研究不同2,4-DNT浓度下细胞的生长情况, 以及不同黄素浓度下2,4-DNT的降解情况。【结果】S. oneidensis MR-1菌能够高效还原转化2,4-DNT为4-氨基-2-硝基甲苯(4A2NT)和2-氨基-4-硝基甲苯(2A4NT), 并将其进一步还原为2,4-二氨基甲苯(2,4-DAT), 黄素能加速转化过程。【结论】S. oneidensis MR-1菌具备高效还原转化2,4-DNT的能力, 为实际环境中硝基苯污染的原位修复提供科学依据。     

Synthesis of 2,6,7-trideoxy-7-C-(2,4-dichlorophenyl)-D-xylo-heptonic acid and 6-(2,4-dichlorophenyl)-D-xylo-2,3,4-tri-hydroxyhexanesulfonic acid.

2,4-O-Benzylidene-L-xylose was converted via a Wittig reaction into Z-2,4-O-benzylidene-5,6-dideoxy-6-C-(2,4-dichlorophenyl)-D-xylo-hex-5-++ +enitol (17), which, on hydrogenation, gave 5,6-dideoxy-6-C-(2,4-dichlorophenyl)-D-xylo- hexitol (33). tert-Butyldimethylsililation of the primary hydroxyl group of 33, followed by 4-methoxybenzylation, and desilylation afforded 5,6-dideoxy-6-C-(2,4-dichlorophenyl)-2,3,4-tri-O-(4-methoxybenzyl)-D-xyl o- hexitol (54). A Mitsunobu-type reaction of 54 replaced HO-1 by cyanide to give, after hydrolysis and hydrogenolysis, 2,6,7-trideoxy-7-C-(2,4- dichlorophenyl)-D-xylo-heptono-1,4-lactone (55). Mesylation of 33 and then acetylation gave 2,3,4-tri-O-acetyl-5,6-dideoxy- 6-C-(2,4-dichlorophenyl)-1-O-methanesulfonyl-D-xylo-hexitol (63), which was converted via its 1-thiobenzoate into bis[1,5,6-trideoxy-6-C-(2,4-dichlorophenyl)-D-xylo-hexitol] 1,1'-disulfide (65). Acetylation of 65, followed by permanganate oxidation and deacetylation, afforded sodium 6-(2,4-dichlorophenyl)-D-xylo- 2,3,4-trihydroxy-hexanesulfonate (67). Both 57 (obtained from 55 by hydrolysis with NaOH) and 67 are weak inhibitors of HMG-CoA reductase.     

Synthesis and antiproliferative activity of 2,6-diamino-9-benzyl-9-deazapurine and related compounds

Treatment of 6-bromomethyl- or 6-dibromomethyl-5-nitropyrimidine-2,4-diamine with KCN gave the same product--(2,6-diamino-5-nitropyrimidinyl)acetonitrile. Benzylation of the nitrile took place on the alpha-carbon to the cyano group preferentially affording the corresponding mono- and dibenzyl derivative, whose reductive cyclization resulted in 7-benzyl-5H-pyrrolo[3,2-d]pyrimidine-2,4-diamine and 7,7-dibenzyl-7H-pyrrolo[3,2-d]pyrimidine-2,4,6-triamine, respectively. Suitability of the protection of N(2) and N(4) atoms with benzyl, acetyl, or benzoyl groups was also investigated. The in vitro evaluation of cell growth inhibition on CCRF-CEM, HL-60, HeLa S3, and L1210 cell lines showed significant activity in 8 new compounds. The most potent compounds were the above mentioned 6-dibromomethyl derivative (IC(50)=0.54, 1.7, 5.0, and 1.9 molL(-1)) and 7,N(2),N(4)-tribenzyl-5H-pyrrolo[3,2-d]pyrimidine-2,4-diamine (IC(50)=1.9, 2.7, 7.3, and 1.0 molL(-1)).     

5-(5-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)pyridin-2-yl)-1H-indole as a potential PET radioligand for imaging cerebral α7-nAChR in mice

The radiosynthesis and in vivo evaluation of 5-(5-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)pyridin-2-yl)-1H-indole [(11)C]rac-(1), a potential PET tracer for α7 nicotinic acetylcholine receptors (α7-nAChR), are described. Syntheses of the nonradioactive standard rac-1 and corresponding desmethyl precursor 7 were achieved in several reaction steps. Radiomethylation of 7 with [(11)C]CH(3)I afforded [(11)C]rac-1 in an average radiochemical yield of 30 ± 5% (n=5) with high radiochemical purity and an average specific radioactivity of 444 ± 74 GBq/μmol (n=5). The total synthesis time was 30 min from end-of-bombardment. Biodistribution studies in mice showed that [(11)C]rac-1 penetrates the blood-brain barrier and specifically labels neuronal α7-nAChRs.     

Final stages of the preliminary metabolism of 2,4,6-trinitrotoluene in Pseudomonas fluorescens

The work was aimed at studying the transformation of 2,4-diamino-6-nitrotoluene (2,4-DA), an intermediate product in 2,4,6-trinitrotoluene catabolism by microorganisms. The results allow one to propose the following scheme for the terminal steps of TNT preparatory metabolism: 2,4-DA----[phloroglucinol carboxylic acid]----phloroglucinol----pyrogallol----ring cleavage.     

Synthesis of new 2,4-Diaminopyrido[2,3-d]pyrimidine and 2,4-Diaminopyrrolo[2,3-d]pyrimidine inhibitors of Pneumocystis carinii,Toxoplasma gondii,and Mycobacterium avium dihydrofolate reductase

A concise new route allowing easy access to five previously unreported 2,4-diamino-6-(substituted benzyl)pyrido[2,3-d]pyrimidines (2a-e) was developed, involving condensation of 2,4-dipivaloylamino-5-bromopyrido[2,3-d]pyrimidine (6) with an organozinc halide in the presence of a catalytic amount of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II).CH(2)Cl(2), followed by removal of the pivaloyl groups with base. Also prepared via a scheme based on the Taylor ring expansion/ring annulation synthesis were three heretofore undescribed 2,4-diamino-5-(substituted benzyl)-7H-pyrrolo[2,3-d]pyrimidines (3b-c). Standard spectrophotometric assays were used to compare the ability of 2a-e and 3b-c to inhibit dihydrofolate reductase (DHFR) from Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium, three examples of opportunistic pathogens to which AIDS patients are highly vulnerable because of their immunocompromised state. For comparison, 13 previously untested 2,4-diamino-6-(substituted benzyl)quinazolines (17a-m) were also evaluated as inhibitors of these enzymes, as well as the enzyme from rat liver. None of the quinazolines or pyridopyrimidines tested was more potent against the P. carinii enzyme than the structurally related reference compound piritrexim (1), and none showed selectivity for the P. carinii enzyme over the rat enzyme. One of the pyridopyrimidines (2c) showed 10-fold selectivity for T. gondii versus rat DHFR, and two of them (2b, 2c) showed selectivity for the M. avium enzyme. However, this gain in species selectivity was achieved at the cost of decreased in potency, as has been noted with many other lipophilic DHFR inhibitors.     

The preparation of 2,4-dibromoestra-1,3,5(10),6-tetraene-3,17 beta-diol diacetate.

[2,4,6,7-3H4]Estradiol is used for the quantitative determination of estradiol receptors. The synthesis of 2,4-dibromoestra-1,3,5(10),6-tetraene-3,17 beta-diol 3,17-diacetate, the convenient precursor of [2,4,6,7-3H4]estradiol, is described. 6-Alkoxy compounds were also prepared and investigated.     

Synthesis, aerobic cytotoxicity, and radiosensitizing activity of novel 2,4-dinitrophenylamine tethered 5-fluorouracil and hydroxyurea

Two novel dual functional agents, 3[3-(2,4-dinitro-phenylamino)-propyl]-5-fluoro-1H-pyrimidine-2,4-dione 7 and N-[3-(2,4-dinitro-phenylamino)-propoxy]urea 8, resulting from linkage of 2,4-dinitrophenylamine through three carbon atoms with 5-fluorouracil 5 and hydroxyurea 6, respectively, were prepared and their in vitro aerobic cytotoxicities in HT-29 cell line with and without radiation were determined. Compounds 7 and 8 unlike their components were not cytotoxic but showed radiosensitizing activity.     

Novel amphiphilic compounds effectively inactivate the vaccinia virus

Recent studies demonstrated the ability of artificial ribonucleases (aRNases, small organic RNA cleaving compounds) to inactivate RNA-viruses via the synergetic effect of viral RNA cleavage and disruption of viral envelope [1,2]. Herein, we describe the antiviral activity of aRNases against DNA-containing vaccinia virus: screening of aRNases of various structures revealed that amphiphilic compounds built of positively charged 1,4-diazabicyclo[2.2.2] octane substituted at the bridge nitrogen atoms with aliphatic residues efficiently inactivate this virus. The first stage was the destruction of viral membrane and structure of surface proteins (electron microscopy data). Thus, 1,4-diazabicyclo[2.2.2] octane-based aRNases are novel universal agents inactivating both RNA- and DNA-containing viruses.     

Synthesis of two phosphate-containing "heptasaccharide" fragments of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B.

The "heptasaccharides" O-alpha-D-galactopyranosyl-(1----3)- O-alpha-D-glucopyranosyl-(1----3)-alpha, beta-L-rhamnopyranose 2'-[O-alpha-D-galactopyranosyl-(1----3)-O-alpha-D-glucopyranosyl- (1----3)-O-alpha-L-rhamnopyranosyl-(1----3)-D-ribit-5-yl sodium phosphate] (25) and O-alpha-D-galactopyranosyl- (1----3)-O-alpha-D-glucopyranosyl-(1----3)-alpha, beta-L-rhamnopyranose 2'-[O-alpha-D-galactopyranosyl-(1----3)-O-alpha-D-glucopyranosyl- (1----3)-O-alpha-L-rhamnopyranosyl-(1----4)-D-ribit-5-yl sodium phosphate] (27), which are structural elements of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B ([----2)- -alpha-D-Galp-(1----3)-alpha-D-Glcp-(1----3)-alpha-L-Rhap- (1----X)-D-RibOH-(5-P----]n; 6A X = 3, 6B X = 4), respectively, have been synthesized. 2,4-Di-O-acetyl- 3-O-[2,4,6-tri-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-alpha-D- galactopyranosyl)-alpha-D-glucopyranosyl]-alpha-L-rhamnopyranosyl trichloroacetimidate (13) was coupled with 5-O-allyloxycarbonyl-1,2,4-tri-O- benzyl-D-ribitol (10), using trimethylsilyl triflate as a promotor (----14), and deallyloxycarbonylation (----15) and conversion into the corresponding triethylammonium phosphonate then gave 16. Condensation of 16 with 4-methoxybenzyl 2,4-di-O-benzyl-3-O-[2,4,6-tri-O-benzyl-3-O-(3,4,6-tri-O-benzyl-alpha-D- galactopyranosyl)-alpha-D-glucopyranosyl]- alpha-L-rhamnopyranoside (22) followed by oxidation and deprotection afforded 25. 5-O-Allyl-1-O-allyloxycarbonyl-2,3-di-O-benzyl-D-ribitol (12) was coupled with 13, using trimethylsilyl triflate as a promoter, the resulting tetrasaccharide-alditol derivative 17 was deallyloxycarbonylated (----18), acetylated (----19), and deallylated (----20), and the product was converted into the triethylammonium phosphonate derivative 21. Condensation of 21 with 22 followed by oxidation and deprotection afforded 27.     

Accumulation of 5-phosphoribosyl-1-pyrophosphate in human CCRF-CEM leukaemia cells treated with antifolates

Amido phosphoribosyltransferase (APRT) catalyzes the first step of the de novo biosynthesis of purine nucleotides, the conversion of 5-phosphoribosyl-1-pyrophosphate (PRPP) into 5-phosphoribosylamine (PRA). APRT is a valid target for development of inhibitors as anticancer drugs. We have developed a thin layer chromatographic assay for PRPP extracted from cells. Using coupling enzymes, PRPP with excess [2-14C]orotate (OA) is quantitatively converted to [2-14C]OMP and then [2-14C]UMP with hydrolysis of the PPi. The reaction products are isolated on poly(ethyleneimine)-cellulose (PEI-C) chromatograms. Human CCRF-CEM leukaemia cells growing in culture have been exposed to a number of antifolates and their effects upon cellular levels of PRPP determined. The steady-state level of PRPP measured in CCRF-CEM cells was 102+/-11 microM. Following addition of an antifolate to a culture, accumulation of PRPP in cells indicates the degree of inhibition of APRT. In human CCRF-CEM leukaemia cells, lometrexol (LTX), 2,4-diamino-6-(3,4,5-trimethoxybenzyl)-5,6,7,8-tetrahydro-quinazoline (PY899), methotrexate (MTX), N(alpha)(4-amino-4-deoxypteroyl)-N(delta)-hemiphthaloyl-L-ornithine (PT523), piritrexim (PTX), metoprine, 2,4-diamino-6-(3,4,5-trimethoxyanilino)-methylpyrido[3,2-d]pyrimidine (PY873) and multitargeted antifolate, N-[4-[2-(2-amino-3,4-dihydro-4-oxo-7H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamic acid (MTA) directly or indirectly induce inhibition of APRT indicated by time-courses for accumulation of PRPP to maximum values of 3-12-fold. These data indicate that LTX induces the most potent inhibition of APRT.     

Dihydrocinnamic acids from Hortia badinii

Hortia badinii (Rutaceae) contains rutecarpine and hortiacine in the bark, as well as coumurrayin, methyl 3-[2-methoxy-6′, 6′-dimethylpyrano(2′,3′:3,4)phenyl]-propionate, 3-[2,6-dimethoxy-6′,6′-dimethylpyrano(2′,3′: 3,4)phenyl]-propionic acid, methyl 3-[2,6-dimethoxy-6′,6′-dimethylpyrano(2′, 3′: 3,4)phenyl]-propionate and methyl 3-[2,4-dimethoxy-3-prenylphenyl]-propionate in the wood.