Pyrazolo[3,4-d]pyrimidines as adenosine antagonists

A large number of nitrogen heterocycles structurally related to caffeine and theophylline have been tested for activity as adenosine antagonists. Preliminary screening, utilizing displacement of [3H]N6-phenylisopropyladenosine (PIA) binding to rat brain membranes, identified several pyrazolo[3,4-d]pyrimidines with potential antagonist activity. These were then tested for their ability to antagonize adenosine-stimulated adenylate cyclase of guinea-pig slices and to block adenosine receptors which mediate presynaptic inhibition of transmitter release from cholinergic nerves in guinea-pig ileum. Of several compounds found to have antagonist activity, one of these, 4,6-bis-alpha- carbamoylethylthio -1-phenylpyrazolo[3,4-d]pyrimidine ( DJB -KK) was approximately an order of magnitude more potent than theophylline in both tests. GTP greatly reduces the potency of purine agonists, but not antagonists, as inhibitors of [3H] PIA binding; the potency of the pyrazolo[3,4-d]pyrimidine compounds was not altered by GTP. The compounds have no significant activity against [3H]adenosine uptake or on the binding of ligands to muscarinic cholinergic, beta-adrenergic, GABA or L-glutamate receptors.     

Production of Tricarboxylic Acid Anhydrides from Fatty Acids by a Lipase-producing Strain of Pseudomonas cepacia

A lipase-producing strain of Pseudomonas cepacia isolated from a soil sample was found to produce five compounds when oleic acid was added to the culture medium as lipase inducer. The five compounds were isolated by solvent extraction, silicagel column chromatography and preparative HPLC, and their structural elucidation was performed by mass spectrometry, and infrared and nuclear magnetic resonance spectroscopies. The products were identified as dec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (product 1 ), undec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (product 2 ), dodec-3-ene-I,3,4-tricarboxylic acid 3,4-anhydride (product 3 ), dodec-3,8-diene-1,3,4-tricarboxylic acid 3,4-anhydride (product 4 ) and dodec-3,6-diene-I,3,4-tricarboxylic acid 3,4-anhydride (product 5 ). Accumulation of these compounds in the culture medium started after oleic acid consumption and followed a pattern similar to that found for cell growth and for lipase production. The five compounds were radioactively labeled when [U- 14 C]oleic acid was supplied to the culture medium, thus showing that they were produced by transformation of the acid. When isolated from cultures containing [1,2- 13 C]acetic acid and oleic acid as the sole sources of carbon, the compounds showed to contain the 13 C isotope only in the first five atoms of carbon of the molecule. Several long chain fatty acids also acted as precursors of these compounds, with maximal yields for chain lengths between 11 and 18 atoms of carbon. None of the five compounds acted as lipase inducer when added to the culture medium instead of oleic acid. The compounds showed moderate antibacterial and antifungal activities when tested in solid media bioassays.     

Production of Tricarboxylic Acid Anhydrides from Fatty Acids by a Lipase-producing Strain of Pseudomonas cepacia

A lipase-producing strain of Pseudomonas cepacia isolated from a soil sample was found to produce five compounds when oleic acid was added to the culture medium as lipase inducer. The five compounds were isolated by solvent extraction, silicagel column chromatography and preparative HPLC, and their structural elucidation was performed by mass spectrometry, and infrared and nuclear magnetic resonance spectroscopies. The products were identified as dec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (product 1 ), undec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (product 2 ), dodec-3-ene-I,3,4-tricarboxylic acid 3,4-anhydride (product 3 ), dodec-3,8-diene-1,3,4-tricarboxylic acid 3,4-anhydride (product 4 ) and dodec-3,6-diene-I,3,4-tricarboxylic acid 3,4-anhydride (product 5 ). Accumulation of these compounds in the culture medium started after oleic acid consumption and followed a pattern similar to that found for cell growth and for lipase production. The five compounds were radioactively labeled when [U- 14 C]oleic acid was supplied to the culture medium, thus showing that they were produced by transformation of the acid. When isolated from cultures containing [1,2- 13 C]acetic acid and oleic acid as the sole sources of carbon, the compounds showed to contain the 13 C isotope only in the first five atoms of carbon of the molecule. Several long chain fatty acids also acted as precursors of these compounds, with maximal yields for chain lengths between 11 and 18 atoms of carbon. None of the five compounds acted as lipase inducer when added to the culture medium instead of oleic acid. The compounds showed moderate antibacterial and antifungal activities when tested in solid media bioassays.     

Microbial Transformation of beta-Ionone and beta-Methylionone

Aspergillus niger JTS 191 was selected from many microorganisms tested as capable of converting ionones to other compounds having aromas. The individual transformation products from beta-ionone were isolated and identified by comparison with synthetically derived compounds. The major products were (R)-4-hydroxy-beta-ionone and (S)-2-hydroxy-beta-ionone. 2-Oxo-, 4-oxo-, 3,4-dehydro-, 2,3-dehydro-4-oxo-, 3,4-dehydro-2-oxo-, (S)-2-acetoxy-, (R)-4-acetoxy-, and 5,6-epoxy-beta-ionone and 4-(2,3,6-trimethylphenyl)-but-3-en-2-one were also identified. Analogous transformation products of beta-methylionone also were identified. Based on gas-liquid chromatographic analysis during the fermentation, we propose two main oxidative pathways of beta-ionone. The results of this study suggest that these transformations of beta-ionones may be useful as tobacco-flavoring compounds.     

Estrogen esters as substrates for human paraoxonases

Mammalian paraoxonases (PONs 1, 2 and 3) are a highly conserved family of esterases, with uncertain physiological functions and natural substrates. Here we characterize the ability of purified recombinant human PONs to hydrolyze estrogen esters, a class of compounds previously not known to be PON substrates. PONs hydrolyzed estrogen mono- and diesters at position 3 of the steroid A-ring. Diesters were better substrates for the PONs and were very efficiently hydrolyzed, particularly by PON3. Esters at position 17 were not cleaved by the PONs unless an adjacent double bound was present. Purified human serum butyryl cholinesterase also hydrolyzed estrogen esters, however it preferably hydrolyzed the mono-esters. The ability of the PONs' to effectively hydrolyze a variety of estrogen esters provides further insight into the structure of their active sites and suggests that natural compounds with aromatic ester groups might be relevant substrates for the PONs.     

Tyrenes: synthesis of new antiproliferative compounds with an extended conjugation

A series of substituted styryl-acrylonitriles was designed and synthesized. The new compounds, called tyrenes, were tested for the ability to inhibit acute lymphocytic leukemia (ALL) cancer cell growth, as well as on their toxicity to normal bone marrow (NBM) cells. The results showed that 3,4-dihydroxystyryl-acrylonitriles, in particular CR-4, revealed great potency as antitumor agents, and also exhibited low toxicity to normal cells. The effectiveness of these compounds with extended conjugation may be due to their possible functioning as reactive Michael acceptors.     

Pyrazolo[3,4-b]quinoxalines. A new class of cyclin-dependent kinases inhibitors

Protein kinases are involved in most physiological processes and in numerous diseases. Therefore, inhibitors of protein kinases have therefore a wide therapeutic potential. While screening for inhibitors of cyclin-dependent kinases (CDK's) and glycogen synthase kinase-3 (GSK-3), we identified pyrazolo[3,4-b]quinoxalines as sub-micromolar inhibitors of CDK1/cyclin B. A preliminary structure-activity relationship study suggests that this family of compounds can be optimized to inhibit CDK's and GSK-3. Compounds were tested for their anti-proliferative activity and the results show that several of them displayed a significant inhibitory effect on CDK1/cyclin B. The most active compound (1) was also tested against the brain kinases CDK5/p25 and GSK-3, and proved to be a good inhibitor of both of them. On the contrary, none of the compounds showed any activity in the CDC25 phosphatase assay. As an additional approach, affinity chromatography on immobilized pyrazolo[3,4-b]quinoxalines will be used to identify the intracellular targets of this family of compounds.     

Kinetic resolution of (±)-diethyl- and dibenzyl hydroxy(phenyl)methanephosphonates and their acyl derivatives with lipases

Abstract

A wide variety of commercially available lipases and microbial whole cells were tested for biotransformations of (±)-diethyl and dibenzyl hydroxyl(phenyl)methanephosphonates. Biocatalytic hydrolysis of acylated hydroxyphosphonates by whole cells of Bacillus subtilis gave optically active compounds with 95%ee _S. Enantioselectivities obtained when using commercially available enzymatic preparations were less satisfactory, leading to both compounds with an enantiomeric excess in the range 15 35%. Screening lipases for their ability to acylate these phosphonates or to hydrolyze their acylated derivatives enabled selection of enzymes and organisms suitable for use in both processes.     

Esterase activity of pure cultures of rumen bacteria as expressed by the hydrolysis of p-nitrophenylpalmitate

Seventy-four strains of rumen bacteria comprising 20 genera were tested for the ability to hydrolyze p-nitrophenylpalmitate (PNPP-C16). This ability was detectable in all cultures tested, but the level of activity was quite variable. Known lipolytic strains of these bacteria showed generally low levels of activity in this assay, which suggests that the hydrolysis of this artificial substrate indicates a general esterase activity and not a lipase activity, as reported in the literature. The highest activity was found to occur in strains known to be feed-particle-associated digesters of starch, pectin and cellulose. In fractionated rumen contents, p-nitrophenylpalmitase activity was largely associated with feed particles. Although the in vivo role of the enzymes that hydrolyze PNPP-C16 remains obscure, it appears that they are primarily of microbial origin, and may be important in hydrolyzing ester bond-containing compounds from plant material.     

Effects of piperine analogues on stimulation of melanocyte proliferation and melanocyte differentiation

A wide range of piperine analogues has been synthesised in order to undertake a structure-activity study of their ability to stimulate melanocyte proliferation. Results demonstrate that an aromatic ring containing at least one ether function and a carbonyl group containing side chain is essential for this activity. A number of highly active piperine analogues have been identified, for instance 1-(3,4-methylenedioxyphenyl)-penta-2E,4E-dienoic acid methyl ester (5a), 1-E,E-piperinoyl-isobutylamine (4f) and 1-(3,4-methylenedioxyphenyl)-pentanoic acid cyclohexyl amide (20). A selection of analogues has also been evaluated for their effect on melanocyte morphology and melanogenesis. The piperine analogues altered cell morphology by increasing dendrite formation leading to bi-, tri- and quadripolar cells. These same analogues were found to increase total melanin in cell cultures, although melanin content per cell was not significantly altered from control in the presence of these compounds.     

High dopamine transporter selectivity can be displayed by remarkably simple non-nitrogen containing inhibitors

A series of 2-(3,4-dichlorophenyl)-cyclopent-1-enyl carboxylic acid esters and amides were prepared and tested for binding to the DAT, SERT, and NET. The achiral compounds were easily attained and found to inhibit DAT binding with K(i)-values ranging from 0.095 to 0.00003 mM. Among the compounds tested 2-(3,4-dichlorophenyl)-cyclopent-1-enyl carboxylic acid 2-methylphenyl ester was found to be highly selective with SERT/DAT>7000; NET/DAT>1700, K(i)=60 nM.     

Design, synthesis, and pharmacological evaluation of new neuroactive pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine derivatives with in vivo hypnotic and analgesic profile

The present study describes the synthesis and pharmacological profiles of four novel pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine derivatives 2-5, which were structurally designed by using the sedative and analgesic drug zolpidem 1 as lead compound. The heterotricyclic system present in the target compounds 2-5 was constructed in good yields, exploiting a regioselective hetero Diels-Alder reaction of the key azabutadiene derivative 7 and functionalized N-phenylmaleimides 9-12. Additionally, we identified that 1-methyl-7-(4-nitrophenyl)-3-phenyl-3,6,7,8-tetrahydropyrazolo[3,4-b]pyrrolo[3,4-d]pyridine-6,8-dione derivative (LASSBio-873, 5) presented not only the most potent ability to promote sedation, which was similar to that induced by the standard benzodiazepine drug midazolam, but also potent central antinociceptive effect.     

花生茎叶酚性成分研究

运用大孔树脂对花生茎叶提取液进行富集,不同浓度乙醇洗脱,硅胶、RP-18、Sephadex LH-20等多种材料进一步分离纯化,研究花生茎叶化学成分,并通过理化方法和光谱分析对化合物进行结构鉴定。结果表明:从花生茎叶大孔树脂10%乙醇洗脱部位中分离并鉴定了10个化合物,分别为邻苯二甲酸二异丁酯(1)、水杨酸(2)、儿茶酚(3)、对羟基苯甲酸(4)、(反)-3,4-二羟基苯丙烯酸(5)、对羟基苯酚(6)、邻苯二甲酸二丁酯(7)、3,4-二羟基苯乙醇(8)、对羟基苯乙醇(9)、3,4-二羟基苯甲酸(10)。除化合物1、2和4外,其余均为首次从该植物中分离得到。     

Organosulphur constituents in garlic oil elicit antennal and behavioural responses from the yellow fever mosquito

Garlic (Allium sativum) and its essential oil have long been used for their distinct flavour, therapeutic effects and as a topical and systemic insect repellent. We tested the hypothesis that the yellow fever mosquito, Aedes aegypti L. (Diptera: Culicidae), responds electrophysiologically and behaviourally to specific components of the steam‐distilled essential oil of garlic. In coupled gas chromatographic‐electroantennographic detection analyses of garlic oil, antennae of female Ae. aegypti responded to 14 compounds. Seven of them [diallyl disulphide, diallyl trisulphide, diallyl tetrasulphide, 2‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 3‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 6‐methyl‐4,5,8,9‐tetrathiadodeca‐1,11‐diene and 4,5,9,10‐tetrathiatrideca‐1,12‐diene] were isolated or synthesized and tested for their ability to repel host‐seeking female Ae. aegypti. A solution of diallyl trisulphide and diallyl tetrasulphide applied to a human forearm provided protection from female mosquitoes significantly longer than the paraffin oil control. All compounds had mean protection times significantly shorter than an equivalent dose of the ‘gold standard’N,N‐diethyl‐3‐methylbenzamide. Understanding the common moiety in organosulfur compounds that causes repellence could lead to the design of analogues that are more effective than their natural counterparts in repelling mosquitoes.     

瓦宁木层孔菌中多酚和黄酮类成分分离及清除自由基活性的研究

采用硅胶和反相C18柱层析方法,首次从瓦宁木层孔菌中分离得到了5个化合物,运用NMR波谱法分析和鉴定为樱花亭、7-甲氧基二氢莰非素、二氢莰非素、4-(3,4-二羟苯基)-3-丁烯-2-酮、hispolon。并通过建立体外二苯基苦味酰基苯肼自由基（·DPPH）、超氧阴离子自由基（·O2?）以及羟自由基（·OH）发生体系,研究了5个化合物对·DPPH、·OH和·O2?的清除作用。结果表明当浓度达到100μg/mL时,化合物4-(3,4-二羟苯基)-3-丁烯-2-酮和hispolon对·DPPH清除率分别为92%和93%,对·OH的清除率分别为90%和95%,而对·O2?的清除率分别为70%和77%,略低于清除·DPPH和·OH的能力;二氢莰非素对·O2?自由基的清除率为39%,强于清除·OH和·DPPH的能力;而樱花亭和7-甲氧基二氢莰非素对3种自由基的清除率均低于30%。2个多酚类化合物清除自由基的能力均强于3个黄酮类化合物。5个化合物清除自由基能力均表现出一定的浓度依赖性。     

6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.     

6-Substituted 3,4-Dihydro-naphthalene-2-carboxylic Acids: Synthesis and Structure-Activity Studies in a Novel Class of Human 5α Reductase Inhibitors

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5 α reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1 - 6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydro-naphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7 - 15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4- (N, N -dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC 50 =0.09 μM, rat type 1), 6-[3- (N, N -dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC 50 =0.75 μM, human type 2; IC 50 =0.81 μM, human type 1) and 6-[4- (N, N -diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC 50 =0.2 μM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki=90 nM; Km, Testosterone=0.8-1.0 μM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.     

Synthesis and antibacterial evaluation of ureides of Baylis-Hillman derivatives

The synthesis of several 1-(2-cyano-3-aryl-allyl)-3-aryl-urea(thiourea) constructed from the reaction between allylamines generated from Baylis-Hillman acetates and substituted isocyanates and isothiocyanates has been described. Further, their cyclization in the presence of a base led to the formation of 5-arylmethyl-4-imino-3-aryl-3,4-dihydro-1H-pyrimidin-2-ones. All compounds were tested for their antibacterial activity. Few of the compounds showed superior activity or were equipotent to the standard antibacterial agents.     

Design,synthesis and evaluation of 3,4-dihydroxybenzoic acid derivatives as antioxidants,bio-metal chelating agents and acetylcholinesterase inhibitors

Abstract

Metal ions, especially copper, zinc and iron, play an important role in the neurodegeneration process because they can affect protein misfolding, leading to the formation of the amyloid deposits and oxidative stress leading to reactive oxygen species (ROS). Here we report the synthesis and evaluation as antioxidant and metal chelating agents of 3,4-dihydroxybenzoic acid derivatives. Synthesized compounds were tested by the 2,2-diphenyl-2-picrylhydrazyl (DPPH) method showing a radical scavenging ability (EC₅₀?=?0.093–0.118?μM) higher than Trolox used as reference. Furthermore, these compounds were able to bind both iron and copper, especially the iron (III), by the formation of hexa-coordinated complexes. Synthesized compounds were tested to evaluate their ability to inhibit acetyl- and butyryl-cholinesterase; the obtained results have demonstrated that they are selective inhibitors of AChE (K_i?=?1.5–18.9?μM) and result weakly active versus butyrylcholinesterase (BChE).     

Variability in essential-oil composition of Piper marginatum sensu lato

This paper contains data on the chemical composition of the essential oils of 22 leaf samples of Piper marginatum Jacq. collected in different areas and ecosystems of the brazilian Amazon, as well as an overview of the available literature. The species presents a large synonymy based on their different leaf characteristics and distinct scents where some of them smell like anise or very close compounds. By GC, GC/MS, and cluster analysis, we identified seven chemotypes for the leaf oils. The main components found in chemotype I were safrole (1) and 3,4-(methylenedioxy)propiophenone (2). The chemotype II was dominated by 3,4-(methylenedioxy)propiophenone (2) and p-mentha-1(7),8-diene (10). The major compounds identified in chemotype III were 3,4-(methylenedioxy)propiophenone (2), myristicin (3), (E)-beta-ocimene (11), and gamma-terpinene (12). In the chemotype IV, the principal constituents were beta-caryophyllene (13), alpha-copaene (14), and 3,4-(methylenedioxy)propiophenone (2). The chemotype V was dominated by (E)-isoosmorhizole (6), (E)-anethole (8), and isoosmorhizole (7). The main compounds found in the chemotype VI were 2-methoxy-4,5-(methylenedioxy)propiophenone (4), methoxy-4,5-(methylenedioxy)propiophenone isomer 5, and (E)-isoosmorhizole (6). The major constituents in chemotype VII were beta-caryophyllene (13), bicyclogermacrene (15), and (E)-asarone (9).