RESUMEN
A novel inhibitor of platelet-activating factor (PAF) acetyltransferase, an essential enzyme in the remodeling pathway of platelet-activating factor synthesis, was identified by a high throughout screen of natural product extracts of microbial origin. The compound, ZG-1494 alpha, was isolated from an ethyl acetate extract of a culture broth of Penicillium rubrum through bioassay guided fractionation. The structure of ZG-1494 alpha was determined by spectroscopic methods. A key feature of the structure, which is relatively rare among natural products, is the 5-hydroxy-3-pyrrolin-2-one moiety. A 13C-13C INADEQUATE was utilized to unambiguously determine the regiochemistry of this molecule.
Asunto(s)
Acetiltransferasas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Penicillium/metabolismo , Animales , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/aislamiento & purificación , Inhibidores Enzimáticos/metabolismo , Células HL-60 , Histamina/metabolismo , Humanos , Estructura Molecular , Factor de Activación Plaquetaria/metabolismo , Unión Proteica , Pirrolidinonas/química , Pirrolidinonas/aislamiento & purificación , Pirrolidinonas/metabolismo , Pirrolidinonas/farmacología , Conejos , Receptores de Glucocorticoides/metabolismoRESUMEN
Plasma membranes of cultured cells contain high affinity receptors for high density lipoprotein (HDL) that appear to mediate removal of excess intracellular cholesterol. Recent studies using ligand blot analysis have identified a 110-kDa membrane protein which has features predicted for an HDL receptor, in that it preferentially binds HDL apolipoproteins and undergoes up-regulation in response to cholesterol loading of cells. In this study, we isolated a cDNA clone from an expression library using an antibody raised against partially purified 110-kDa HDL-binding protein. This clone encodes a novel cell protein, designated HBP, comprised mostly of 14 imperfect tandem repeats of approximately 70 amino acids in length. Each repeat appears to contain two amphipathic helices. Expression of HBP in cultured cells was increased severalfold when cells were loaded with cholesterol, as evident by increases in both HBP mRNA and membrane-associated protein. Overexpression of HBP in mammalian cell transfectants was associated with higher HDL binding to isolated cell protein and with modest increases in HDL binding to the cell surface. Proteins identified by ligand blot analysis had lower apparent M(r) than the primary HBP gene product and varied in M(r) and in HDL binding activity between cell types, suggesting that HBP undergoes cell-specific processing. These results provide preliminary evidence that HBP is a component of a cellular pathway that facilitates removal of excess cholesterol from cells, perhaps through its interaction with HDL. However, the predicted structure of HBP does not conform to that of any known receptor, suggesting that it does not function as a classic plasma membrane receptor.
Asunto(s)
Proteínas Portadoras , Colesterol/farmacología , Lipoproteínas HDL/metabolismo , Proteínas de Unión al ARN , Receptores de Superficie Celular/genética , Receptores de Lipoproteína , Regulación hacia Arriba , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Western Blotting , Bovinos , Células Cultivadas , Clonación Molecular , ADN/genética , Expresión Génica , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Receptores de Superficie Celular/metabolismo , Alineación de Secuencia , Células Tumorales CultivadasRESUMEN
The in vitro antiviral activity of 28 nucleosides against the parainfluenza virus type 3 has been analyzed by using a novel computer aided receptor modeling procedure. The method involves an extensive modification of our earlier work (Ghose, A. K.; Crippen, G. M. J. Med. Chem. 1985, 28, 333). It presents a more straightforward algorithm for the steps that suffered from subjectivity in the earlier method. The method first determines the possible low-energy conformations of the nucleosides, and assigns a priority value for each conformation of each molecule. It then performs the following steps repeatedly, until it finds an acceptable solution. Starting from the conformation of highest priority, the various energetically allowed conformations of the other molecules are superimposed on it. On the basis of the physicochemical property matching (or overlapping), the best superposition is determined. The superimposed molecules are dissected into a minimum number of parts and the local physicochemical properties at different regions are correlated with their binding data (antiviral activity). A modified version of distance geometry has been used for geometric comparison of the structure of the molecules. On the basis of the virus rating (VR) of 28 ribonucleosides, this procedure hypothesized the minimum-energy conformation of 6-(methylthio)-9-beta-D-ribofuranosylpurine as a reference conformation and used three physicochemical properties, namely hydrophobicity, molar refractivity, and formal charge density for property matching. The binding-site cavity was divided into seven regions or pockets to differentiate the nature of interaction quantitatively. The model suggests that the 2- and 3-positions of the purine ring and the corresponding atoms of the other rings get some steric repulsion, and nucleosides having a single five-membered heterocyclic ring will better fit this virus. The methylthio group gets a strong attraction from dispersive interaction. Both hydrophilic and dispersive groups are attractive here. Although our calculation supports the previously suggested active conformation of ribavirin, it shows that it is not the global minimum-energy conformation. The difference lies in the orientation of the amide group. The calculated viral rating from this model showed a correlation coefficient of 0.971 with the observed values, and the explained variance and the standard deviation of the fit were 0.880 and 0.125, respectively.
Asunto(s)
Diseño de Fármacos , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Receptores Virales/metabolismo , Respirovirus/efectos de los fármacos , Ribonucleósidos/farmacología , Antivirales , Sitios de Unión , Fenómenos Químicos , Química , Química Física , Simulación por Computador , Modelos Químicos , Modelos Moleculares , Conformación Molecular , Estructura Molecular , Ribonucleósidos/metabolismo , Relación Estructura-ActividadRESUMEN
Eight sugar-modified pyrrolopyrimidine nucleoside analogs related to the antibiotic sangivamycin were evaluated in cell culture against herpes simplex types 1 (HSV-1) and 2 (HSV-2), cytomegalovirus (CMV), adenovirus, and visna virus. Five of the compounds were highly active against most of the viruses with 50% inhibition (ED50) values of 1-10 microM. The selectivity of the agents was low, with inhibition of uninfected cell proliferation occurring within 5-fold that of the virus ED50 for most of the viruses. The compounds did not possess RNA virus-inhibitory activity when evaluated against certain myxo-, paramyxo-, picorna-, reo-, rhabdo-, and togaviruses. Two of the nucleosides were tested further in a cell line persistently infected with Friend leukemia virus where they were inhibitory to both virus yield and cell proliferation at 4-5 microM. Several of the sangivamycin analogs were tested in animal models using a twice-a-day treatment regimen. They proved to be inactive against HSV-1, murine CMV and/or Friend leukemia virus infections in mice.
Asunto(s)
Antivirales/farmacología , Virus ADN/efectos de los fármacos , Retroviridae/efectos de los fármacos , Adenoviridae/efectos de los fármacos , Animales , Antivirales/uso terapéutico , División Celular/efectos de los fármacos , Línea Celular , Citomegalovirus/efectos de los fármacos , Infecciones por Citomegalovirus/tratamiento farmacológico , Virus de la Leucemia Murina de Friend/efectos de los fármacos , Herpes Simple/tratamiento farmacológico , Humanos , Leucemia Experimental/tratamiento farmacológico , Ratones , Estructura Molecular , Nucleósidos de Pirimidina/farmacología , Nucleósidos de Pirimidina/uso terapéutico , Simplexvirus/efectos de los fármacos , Células Tumorales Cultivadas , Células Vero , Virus Visna-Maedi/efectos de los fármacosRESUMEN
A novel nucleoside analog, 4(5H)-oxo-1-beta-D- ribofuranosylpyrazolo[3,4-d]pyrimidine-3-thiocarboxamide (N10169), was evaluated in cell culture and in animals for antiviral activity against DNA and RNA viruses. The compound was highly active against strains of adeno-, vaccinia, influenza B, paramyxo-, picorna-, and reoviruses, with 50% inhibition of virus-induced cytopathology at 1 to 10 microM. Lesser or no antiviral effects were observed against herpes simplex, cytomegalo-, corona-, influenza A, vesicular stomatitis, and visna viruses. Drug potency against certain viruses was highly cell line dependent (N10169 was highly active in HeLa cells but was much less potent in Vero cells). This was correlated, in part, to differences in levels of adenosine kinase activity in these cell lines, since adenosine kinase appears to phosphorylate N10169 to its active form. N10169 was inhibitory to proliferating cells at antiviral concentrations, whereas stationary-phase monolayers tolerated higher concentrations (less than or equal to 100 microM). Exogenous uridine was able to reverse the virus-inhibitory effects of the compound, leading to the discovery that N10169 5'-monophosphate is a potent inhibitor of cellular orotidylate decarboxylase. N10169 was evaluated in mice that were infected intraperitoneally with banzi virus or inoculated intranasally with influenza B virus, and in hamsters that were infected intranasally with vaccinia virus. In each model, intraperitoneal injection of N10169 (100 to 300 mg/kg per day for 7 days) twice daily was ineffective, whereas intraperitoneal injection of ribavirin showed some benefit in the influenza B and banzi virus infection models.
Asunto(s)
Antivirales/farmacología , Ribonucleósidos/farmacología , Animales , Antivirales/uso terapéutico , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cricetinae , Células HeLa , Humanos , Ratones , Virus ARN/efectos de los fármacos , Ribavirina/farmacología , Ribonucleósidos/uso terapéutico , Virus Vaccinia/efectos de los fármacos , Virosis/tratamiento farmacológicoRESUMEN
Inhibition of visna virus replication in vitro by several compounds previously reported to inhibit replication of human immunodeficiency virus (HIV) was examined. Ribavirin concentrations as high as 1 mM reduced virus production by less than 50% relative to controls. The concentration of phosphonoformate reducing virus replication by 50% was 80 microM. 2',3'-Dideoxynucleosides were potent inhibitors of visna virus replication. The 50% inhibitory concentrations for dideoxyguanosine, dideoxyadenosine, and dideoxycytidine were 0.1, 0.2, and 0.3 microM, respectively. In contrast, weak inhibition was produced by 100 microM dideoxythymidine. These results are consistent with the reported susceptibility of HIV replication to inhibition by these compounds in vitro. The interaction of visna virus reverse transcriptase with several inhibitors was also examined. Reverse transcriptase was inhibited by phosphonoformate, ribavirin 5'-triphosphate, ddATP, ddCTP, ddGTP, and ddTTP. The last four compounds inhibited incorporation of homologous 2'-deoxynucleoside 5'-triphosphates into polynucleotides by a competitive mechanism. In view of the biological similarities between visna virus and HIV and the similar in vitro susceptibility of visna virus replication to known inhibitors of HIV, visna virus may provide a good model for studying the inhibition of HIV replication in vitro. Because visna virus is not pathogenic to humans, this model may facilitate the identification of compounds for further investigation into the treatment of HIV-induced disease.
Asunto(s)
Antimetabolitos/farmacología , Antivirales , Desoxirribonucleósidos/farmacología , VIH/efectos de los fármacos , Compuestos Organofosforados/farmacología , Ácido Fosfonoacético/farmacología , Inhibidores de la Transcriptasa Inversa , Ribavirina/farmacología , Ribonucleósidos/farmacología , Replicación Viral/efectos de los fármacos , Virus Visna-Maedi/efectos de los fármacos , Desoxirribonucleótidos/metabolismo , Foscarnet , Ácido Fosfonoacético/análogos & derivadosRESUMEN
2-Deoxy-beta-D-ribo-hexopyranosyl nucleosides with adenine (2), hypoxanthine (17), guanine (23), cytosine (13), and uracil (7) as the aglycon were synthesized by the Lewis-acid catalyzed condensation of an appropriate trimethylsilylated heterocyclic base and 2-deoxy-1,3,4,6-tetrakis-O-(4-nitrobenzoyl)-beta-D-ribo-hexopyranose+ ++ (5) to provide the desired beta anomers in good yield. When the synthesis of 7 via an SN2 displacement was attempted by reaction between silylated uracil and 2-deoxy-3,4,6-tris-O-(4-nitrobenzoyl)-alpha-D-ribo-hexopyranosyl bromide (8), the major product, 1-(2-deoxy-3,4,6-tris-O-(4-nitrobenzoyl)-alpha-D-ribo-hexopyranosyl)-2,4 - pyrimidinedione (9), had retained the alpha configuration at the anomeric carbon. The structures of both anomers of 1-(2-deoxy-D-ribo-hexopyranosyl)-2,4-pyrimidinedione were assigned by single-crystal X-ray methods. The anomeric configuration and conformation of other nucleosides were determined by proton magnetic resonance analysis of the 4-nitrobenzoylated nucleosides. Nucleoside 6'-monophosphates of 7, 13, and 2 and the 4',6'-cyclic monophosphate of 2 were also prepared. All 2'-deoxy-D-ribo-hexopyranosyl nucleosides and 6'-monophosphate derivatives were tested in vitro for antiviral and antitumor activity. The guanosine analogue 23 was moderately active against HSV-2 virus. The UMP analogue, 1-(2-deoxy-6-O-phosphono-beta-D-ribo-hexopyranosyl) -2,4-pyrimidinedione (28), demonstrated moderate activity against HSV-2 and parainfluenza 3 virus and was also active against L1210 (ID50 = 39 microM) and P388 (ID50 = 33 microM) leukemic cell lines. Two compounds, 6-amino-9-(2-deoxy-beta-D-ribo-hexopyranosyl)purine (2) and 9-(2-deoxy-beta-D-ribo-hexopyranosyl)-2,6-diaminopurine (24), were substrates for adenosine deaminase (EC 3.5.4.4) with Km values of 57 and 90 microM, respectively. 6-Amino-7-(2-deoxy-beta-D-ribo-hexopyranosyl)purine, 18, was a competitive inhibitor of ADase (Ki = 0.1 mM).
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Nucleósidos/síntesis química , Nucleótidos/síntesis química , Adenosina Desaminasa/análisis , Animales , Antineoplásicos/farmacología , Antivirales/farmacología , Cinética , Espectroscopía de Resonancia Magnética , Ratones , Conformación Molecular , Nucleósidos/farmacología , Nucleótidos/farmacología , Proteínas Quinasas/análisis , Difracción de Rayos XRESUMEN
Several 3-beta-D-ribofuranosyl-1,2,4-triazolo[3,4-f]-1,2,4-triazines related to formycin were prepared and tested for their antitumor activity in cell culture. Dehydrative coupling of 3-amino-6-hydrazino-1,2,4-triazin-5(4H)-one (5) with 3,4,6-tri-O-benzoyl-2,5-anhydro-D-allonic acid (6a) and further ring closure of the reaction product (7) provided 6-amino-3-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-1,2,4-triazolo[3,4- f]-1,2,4-triazin-8(7H)-one (8). Condensation of 5 with 3,4,6-tri-O-benzoyl-2,5-anhydro-D-allonic acid chloride (6b), followed by ring annulation, also gave 8 in good yield. Debenzoylation of 8 furnished the guanosine analogue 6-amino-3-beta-D-ribofuranosyl-1,2,4-triazolo[3,4-f]-1,2,4-triazin -8(7H)-one (4b). Thiation of 8 with P2S5, followed by debenzoylation of the thiated product (11a), afforded 6-amino-3-beta-D-ribofuranosyl-1,2,4-triazolo[3,4-f]-1,2,4-triazin -8(7H)- thione (11b). Methylation of the sodium salt of 11a gave the 8-methylthio derivative (10), which on ammonolysis furnished 6,8-diamino-3-beta-D-ribofuranosyl-1,2,4-triazolo[3,4-f]-1,2,4-triazine (9). Diazotization of 10 with tert-butyl nitrite (TBN) and SbCl3 in 1,2-dichloroethane gave the corresponding 6-chloro derivative (12a). Reaction of 10 with TBN in THF in the absence of a halogen source gave 8-(methylthio)-3-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-1,2,4- triazolo[3,4-f]-1,2,4-triazine (12b). Ammonolysis of 12b gave the azaformycin A analogue 8-amino-3-beta-D-ribofuranosyl-1,2,4- triazolo[3,4-f]-1,2,4-triazine (3), which on deamination afforded 3-beta-D-ribofuranosyl-1,2,4-triazolo[3,4- f]-1,2,4-triazin-8(7H)-one (4a). The azaformycin A analogue (3) showed pronounced inhibitory effects against L1210, WIL2, and CCRF-CEM cell lines with ID50 values ranging from 5.0 to 7.3 microM.
Asunto(s)
Antibióticos Antineoplásicos/síntesis química , Antineoplásicos/síntesis química , Formicinas/síntesis química , Ribonucleósidos/síntesis química , Antineoplásicos/farmacología , Células Cultivadas , Formicinas/farmacología , Formicinas/toxicidad , Leucemia Experimental/tratamiento farmacológico , Ribonucleósidos/farmacología , Triazinas/síntesis química , Triazinas/farmacología , Triazoles/síntesis química , Triazoles/farmacologíaRESUMEN
(Ethoxycarbonyl)phosphonic dichloride (3) was synthesized by chlorination of bis(trimethylsilyl) (ethoxycarbonyl)phosphonate with thionyl chloride. Adenosine 5'-(ethoxycarbonyl)phosphonate (4), guanosine 5'-(ethoxycarbonyl)phosphonate (5), 2'-deoxyadenosine 5'-(ethoxycarbonyl)phosphonate (18) and 2'-deoxyguanosine 5'-(ethoxycarbonyl)phosphonate (19) were synthesized by coupling of compound 3 with adenosine, guanosine, 2'-deoxyadenosine, and 2'-deoxyguanosine, respectively. Alkaline treatment of 4, 5, 18, and 19 gave the corresponding adenosine 5'-(hydroxycarbonyl)phosphonate (14), guanosine 5'-(hydroxycarbonyl) phosphonate (15), 2'-deoxyadenosine 5'-(hydroxycarbonyl)phosphonate (20), and 2'-deoxyguanosine 5'-(hydroxycarbonyl) phosphonate (21). Treatment of 4 and 5 with methanolic ammonia resulted in the production of adenosine 5'-(aminocarbonyl)phosphonate (12) and guanosine 5'-(aminocarbonyl)phosphonate (13), respectively. The nucleotide analogue 20 exhibited the most potent antiviral activity of this group of nucleotide tested in vitro and was most active against herpes viruses especially HSV-2. The nucleotide analogue 21 had lower, but significant, activity against HSV-2. All of the compounds tested were nontoxic to confluent Vero cells at concentrations as high as 5000 microM.
Asunto(s)
Antivirales/síntesis química , Nucleósidos , Compuestos Organofosforados , Ácido Fosfonoacético/análogos & derivados , Animales , Línea Celular , Chlorocebus aethiops , Deltaretrovirus/efectos de los fármacos , Foscarnet , Concentración de Iones de Hidrógeno , Leucemia L1210/tratamiento farmacológico , Leucemia P388/tratamiento farmacológico , Ratones , Nucleósidos/farmacología , Ácido Fosfonoacético/farmacología , Simplexvirus/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
A number of nucleoside and nucleotide derivatives of 4-hydroxy-3-beta-D-ribofuranosylpyrazole-5-carboxamide (pyrazofurin, 1) were prepared and tested for their antiviral and cytostatic activity in cell culture. Treatment of 1 with benzyl bromide gave 4-O-benzylpyrazofurin (4). Methylation of 4 with CH2N2 and subsequent removal of the benzyl group by catalytic hydrogenation provided 1-methylpyrazofurin (8). Direct methylation of 1 with CH3I furnished 4-O-methylpyrazofurin (6). Dehydration of the pentaacetylpyrazofurin (9) with phosgene furnished 4-acetoxy-3-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-1-acetylpyrazol e-5-carbonitrile (10). A similar dehydration of the precursor tetraacetyl derivative of 4 gave the corresponding carbonitrile, which on deprotection and subsequent treatment with hydroxylamine furnished 4- (benzyloxy)-3-beta-D-ribofuranosylpyrazole-5-carboxamidoxime (13). Treatment of the tetraacetyl derivative of 4 with Lawesson's reagent and subsequent deacetylation furnished a mixture of 4- (benzyloxy)-3-beta-D-ribofuranosylpyrazole-5-thiocarboxamide (15) and the corresponding nitrile derivative (16). Phosphorylation of unprotected 4 with POCl3 and subsequent debenzylation of the intermediate 17 gave pyrazofurin 5'-phosphate (18), which provided the first chemical synthesis of 18. Similar phosphorylation of 4 with POCl3 and quenching the reaction mixture with either EtOH or MeOH, followed by debenzylation, furnished the 5'-O-(ethyl phosphate) (19b) and 5'-O-(dimethyl phosphate) (20b) derivatives of pyrazofurin. DCC-mediated cyclization of 17, followed by debenzylation, gave pyrazofurin 3',5'-(cyclic)phosphate (21b). The NAD analogue 23b was also prepared by the treatment of 17 with an activated form of AMP in the presence of AgNO3. The structural assignment of 7,8, and 20a were made by single-crystal X-ray analysis, and along with pyrazofurin, their intramolecular hydrogen bond characteristics have been studied. All of these compounds were tested in Vero cell cultures against a spectrum of viruses. Compounds 18 and 23b were active at concentrations very similar to pyrazofurin but are less toxic to the cells than pyrazofurin. Compounds 19b, 20b, and the 3',5'-(cyclic)phosphate 21b are less active than 1. Compounds 18, 19b, 20b, and 23b also exhibited significant inhibitory effects on the growth of L1210 and P388 leukemias and Lewis lung carcinoma cells in vitro, whereas B16 melanoma cells were less sensitive to growth inhibition by these compounds. Pyrazofurin derivatives modified at the 1-, 4-, or 5-position showed neither antiviral nor cytostatic activity in cell culture.
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Nucleósidos/síntesis química , Nucleótidos/síntesis química , Ribonucleósidos/síntesis química , Amidas , Animales , Antineoplásicos/farmacología , Antivirales/farmacología , Enlace de Hidrógeno , Leucemia Experimental/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Melanoma/tratamiento farmacológico , Ratones , Nucleósidos/farmacología , Nucleótidos/farmacología , Pirazoles , Ribonucleósidos/farmacología , Ribosa , Relación Estructura-Actividad , Difracción de Rayos XRESUMEN
A number of 6-substituted and 2,6-disubstituted pyrrolo[2,3-d]pyrimidine 2'-deoxyribonucleosides were prepared by the direct stereospecific sodium salt glycosylation procedure. Reaction of the sodium salt of 4-chloro-6-methyl-2-(methylthio)pyrrolo[2,3-d]pyrimidine (6a) or 4,6-dichloro-2-(methylthio)pyrrolo[2,3-d]pyrimidine (6b) with 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-alpha-D-erythro-pentofuranose (9) provided the corresponding N7 2'-deoxy-beta-D-ribofuranosyl blocked derivatives (8a and 8c) which, on ammonolysis, gave 4-amino-6-methyl-2-(methylthio)-7-(2-deoxy-beta-D-erythro-pentofuranosyl )pyrrolo[2,3-d]pyrimidine (11a) and 4-amino-6-chloro-2-(methylthio)-7-(2-deoxy-beta-D-erythro-pentofuranosyl )pyrrolo[2,3-d]pyrimidine (11b), respectively. Dethiation of 11a and 11b afforded 6-methyl-2'-deoxytubercidin (10a) and 6-chloro-2'-deoxytubercidin (10b), respectively. Dehalogenation of 10b provided an alternate route to the reported 2'-deoxytubercidin (3a). Application of this glycosylation procedure to 4,6-dichloro and 4,6-dichloro-2-methyl derivatives of pyrrolo[2,3-d]pyrimidine (15a and 15b) gave the corresponding blocked 2'-deoxyribonucleosides (18a and 18b), which on ammonolysis furnished 10b and 4-amino-6-chloro-2-methyl-7-(2-deoxy-beta-D-erythro- pentofuranosyl)pyrrolo[2,3-d]pyrimidine (17), respectively. This stereospecific attachment of the 2-deoxy-beta-D-ribofuranosyl moiety appears to be due to a Walden inversion at the C1 carbon by the anionic heterocyclic nitrogen. Controlled deacylation of 4-chloro-7-(2-deoxy-3,5-di-O-p-toluoyl-beta-D-erythro-pentofuranosyl) pyrrolo[2,3-d]pyrimidine (20a) gave 4-chloro-7-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrrolo[2,3-d] pyrimidine (20b). Dehalogenation of 20b gave the 2'-deoxynebularin analogue 7-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrrolo[2,3-d]pyrimidine (19), and reaction of 20b with thiourea gave 7-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrrolo[2,3-d]pyrimidine-4(3H)- thione (21). All of these compounds were tested in vitro against certain viruses and tumor cells. Only compounds 12a, 20b, and 21 showed significant activity against measles in vitro, and the activity is comparable to that of ribavirin. Although compounds 3a and 12b are slightly more active than ribavirin against HSV-2 in vitro, they are relatively more toxic to Vero cells. Compounds 3a and 20b exhibited moderate cytostatic activity against L1210 and P388 leukemia in vitro but are considerably less active than 2-chloro-2'-deoxyadenosine (1).
Asunto(s)
Antivirales/síntesis química , Ribonucleósidos/síntesis química , Tubercidina/síntesis química , Animales , Antivirales/farmacología , División Celular/efectos de los fármacos , Células Cultivadas , Virus del Sarampión/efectos de los fármacos , Ratones , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Simplexvirus/efectos de los fármacos , Estereoisomerismo , Tubercidina/análogos & derivados , Virus Vaccinia/efectos de los fármacos , Replicación Viral/efectos de los fármacosRESUMEN
A number of 5-substituted imidazole-4-carboxamide ribonucleosides were prepared and tested for their biological activity. Treatment of 5-chloro-1-beta-D-ribofuranosylimidazole-4-carboxamide (2) with methanethiol provided 5-(methylthio)-1-beta-D-ribofuranosylimidazole-4-carboxamide (3a). Similar treatment of 2 with ethanethiol or benzenemethanethiol gave the corresponding 5-ethylthio and 5-benzylthio derivatives 3b and 3c. Oxidation of 3a and 3b with m-chloroperoxybenzoic acid furnished the corresponding sulfonyl derivatives 4a and 4b. Reductive cleavage of 3c with sodium naphthalene or Na/NH3 gave 5-mercapto-1-beta-D-ribofuranosylimidazole-4-carboxamide (5-thiobredinin, 5). Direct treatment of 2 with sodium hydrosulfide provided an alternate route to 5, the structure of which was established by single-crystal X-ray analysis. 5-Thiobredinin has a zwitterionic structure similar to that of bredinin. Glycosylation of persilylated ethyl 5(4)-methylimidazole-4(5)-carboxylate (6) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in the presence of SnCl4 provided a quantitative yield of the corresponding tri-O-benzoyl nucleoside 7. Debenzoylation of 7 with MeOH/NH3 at ambient temperature gave ethyl 5-methyl-1-beta-D-ribofuranosylimidazole-4-carboxylate (8). Further ammonolysis of 8 or 7 at elevated temperature and pressure gave 5-methyl-1-beta-D-ribofuranosylimidazole-4-carboxamide (9). All of these ribonucleosides were tested in Vero cell cultures and in mice against certain viruses. Compounds 3a and 3c exhibited significant activity against vaccinia virus in vitro, whereas 4a was effective against Rift Valley fever virus in mice. 5-Thiobredinin failed to exhibit appreciable antiviral or cytostatic activity (against L1210 and P388) in cell culture.
Asunto(s)
Aminoimidazol Carboxamida/uso terapéutico , Imidazoles/uso terapéutico , Ribonucleósidos/uso terapéutico , Virus/efectos de los fármacos , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/síntesis química , Aminoimidazol Carboxamida/farmacología , Animales , Fenómenos Químicos , Química , Leucemia L1210/tratamiento farmacológico , Leucemia P388/tratamiento farmacológico , Ratones , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Ribavirina/farmacología , Ribonucleósidos/síntesis química , Ribonucleósidos/farmacología , Virus de la Fiebre del Valle del Rift/efectos de los fármacos , Simplexvirus/efectos de los fármacos , Togaviridae/efectos de los fármacos , Virus Vaccinia/efectos de los fármacos , Difracción de Rayos XRESUMEN
Several 3,4,6-trisubstituted pyrazolo[3,4-d]pyrimidine ribonucleosides were prepared and tested for their biological activity. High-temperature glycosylation of 3,6-dibromoallopurinol with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in the presence of BF3 X OEt2, followed by ammonolysis, provided 6-amino-3-bromo-1-beta-D-ribofuranosylpyrazolo-[3,4-d]pyrimidin-4(5H)-on e. Similar glycosylation of either 3-bromo-4(5H)-oxopyrazolo [3,4-d]pyrimidin-6-yl methyl sulfoxide or 6-amino-3-bromopyrazolo [3,4-d]pyrimidin-4(5H)-one, and subsequent ammonolysis, also gave 7a. The structural assignment of 7a was on the basis of spectral studies, as well as its conversion to the reported guanosine analogue 1d. Application of this glycosylation procedure to 6-(methylthio)-4(5H)-oxopyrazolo[3,4-d]pyrimidine-3-carboxamide gave the corresponding N-1 glycosyl derivative. Dethiation and debenzoylation of 16a provided an alternate route to the recently reported 3-carbamoylallopurinol ribonucleoside thus confirming the structural assignment of 16a and the nucleosides derived therefrom. Oxidation of 16a and subsequent ammonolysis afforded 6-amino-1-beta-D-ribofuranosyl-4(5H)-oxopyrazolo[3, 4-d]pyrimidine-3-carboxamide. Alkaline treatment of 15a gave 6-azacadeguomycin. Acetylation of 15a, followed by dehydration with phosgene, provided the versatile intermediate 6-amino-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-4(5H)-oxopyrazolo [3, 4-d]pyrimidine-3-carbonitrile. Deacetylation of 19 gave 6-amino-1-beta-D-ribofuranosyl-4(5H)-oxopyrazolo[3, 4-d]pyrimidine-3-carbonitrile. Reaction of 19 with H2S gave 6-amino-1-beta-D-ribofuranosyl-4(5H)-oxopyrazolo[3, 4-d]pyrimidine-3-thiocarboxamide. All of these compounds were tested in vitro against certain viruses and tumor cells. Among these compounds, the guanosine analogues 7a and 20a showed significant activity against measles in vitro and were found to exhibit moderate antitumor activity in vitro against L1210 and P388 leukemia. 6-Azacadeguomycin and all other compounds were inactive against the viruses and tumor cells tested in vitro.
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Ribonucleósidos/farmacología , Animales , Antibióticos Antineoplásicos/síntesis química , Células Cultivadas , Efecto Citopatogénico Viral/efectos de los fármacos , Guanosina/análogos & derivados , Guanosina/síntesis química , Guanosina/farmacología , Leucemia Experimental/tratamiento farmacológico , Metotrexato/análogos & derivados , Ratones , Ribonucleósidos/síntesis química , Relación Estructura-ActividadRESUMEN
A series of 1-beta-ribofuranosyl-5-halocytosine cyclic 3',5'-monophosphates (1-4) has been prepared. Direct halogenation of cytidine 3',5'-monophosphate (cCMP) yielded the Cl, Br, and I compounds while 5-F-cCMP (1) was obtained on cyclization of the 5'-monophosphate. On in vitro testing of 1-4 against L1210 and P388 leukemias, only 1 showed significant low-level activity (ID50 = 3.1 X 10(-4) mmol/L). Derivatives 2-4 were inactive at 10(-1) mmol/L and also proved to have low viral ratings against a series of RNA and DNA virus strains in vitro. By contrast the 5-F-cCMP showed moderate activity against VV, HSV-1, and HSV-2 strains (VR = 0.6-0.9). Both 5-fluorocytidine and 5-fluorocytidine 5'-monophosphate had marked antiviral activity (VR = 1.0-2.1) with the above viruses as well as with parainfluenza virus type 3. The nucleoside and nucleotide also were more active than 5-F-cCMP against L1210 and P388 cells. However, comparison of the cytotoxicities and antiviral ED50 values of 5-F-cCMP, 5-fluorocytidine 5'-monophosphate, and 5-fluorocytidine suggests a potential therapeutic advantage for 5-F-cCMP. Possible rationales for these activities are discussed in terms of 5-F-cCMP and the corresponding 5'-monophosphate as potential prodrugs and as sources, following enzymatic deamination, of cytotoxic 5-fluorouridine or its 5'-monophosphate.
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , CMP Cíclico/síntesis química , Nucleótidos de Citosina/síntesis química , Animales , Antineoplásicos/farmacología , Antivirales/farmacología , CMP Cíclico/análogos & derivados , CMP Cíclico/farmacología , Leucemia Experimental/tratamiento farmacológico , Ratones , Proteínas Quinasas/análisisRESUMEN
The nucleosides ribavirin, selenazofurin, tiazofurin and bredinin all exhibit the lowering of guanylate pools in vitro and in vivo by the inhibition of IMP dehydrogenase. However, each of these nucleosides has a separate profile of antiviral and antitumor activity. The IMP dehydrogenase inhibition in the case of ribavirin and bredinin appears to be due to the nucleoside 5'-monophosphate and in the case of selenazofurin and tiazofurin to the NAD analogs formed intracellularly. With regard to the antiviral activity of these nucleosides, although selenazofurin was the most potent antiviral agent in vitro, its antiviral activity was also most readily reversed by exogenous guanosine. The antiviral effects of ribavirin were only partially reversed under the conditions studied. These and related studies show that each of these nucleosides form nucleotide metabolites which act as enzyme inhibitors at additional sites other than IMP dehydrogenase. As in the case of ribavirin such inhibition of IMP dehydrogenase may result in an increased "self potentiation" by the lowering of guanylate pools in those instances where guanylate analogs are involved as inhibitors of viral specific or viral induced enzymes. Further studies should more clearly elucidate the importance of the simultaneous inhibition of various enzyme sites by different metabolic nucleotide forms of the same nucleoside analog.
Asunto(s)
Antivirales/farmacología , IMP Deshidrogenasa/antagonistas & inhibidores , Cetona Oxidorreductasas/antagonistas & inhibidores , Compuestos de Organoselenio , Ribavirina/farmacología , Ribonucleósidos/farmacología , Selenio/farmacología , Línea Celular , Guanosina/farmacología , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Virus de la Parainfluenza 3 Humana/enzimología , Virus Vaccinia/efectos de los fármacos , Virus Vaccinia/enzimologíaRESUMEN
A new procedure for the preparation of the antiviral and antitumor agent 3-deazaguanine (1) and its metabolite 3-deazaguanosine (2) has been developed by reacting methyl 5(4)-(cyanomethyl) imidazole-4(5)-carboxylate (4) and 5-(cyanomethyl)-1- (2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)imidazole-4-carboxylate (6), respectively, with hydrazine. The 3-deazaguanosine 3',5'-cyclic phosphate (13) was prepared from 5-(cyanomethyl)-1-beta-D-ribofuranosyl-imidazole-4-carboxamide 5'-phosphate. Glycosylation of the trimethylsilyl 4 with 1-O-methyl-2-deoxy-3,5-di-O-p-toluoyl-D-ribofuranose in the presence of trimethylsilyl trifluoromethanesulfonate gave the corresponding N-1 and N-3 glycosyl derivatives with alpha-configuration (18 and 20) as the major products, along with minor amounts of the beta-anomers (19 and 21). However, glycosylation of the sodium salt of 4 with 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-alpha-D-erythro-pentofurano se (17) gave exclusively the beta-anomers (19 and 21) in good yield. Base-catalyzed ring closure of these imidazole nucleosides gave 2'-deoxy-3-deazaguanosine (29), the alpha-anomer 28, and the corresponding N-3 positional isomers 27 and 26. The site of glycosylation and the anomeric configuration of these nucleosides have been assigned on the basis of 1' NMR and UV spectral characteristics and by single-crystal X-ray analysis for 27-29. In a preliminary screening, several of these compounds have demonstrated significant broad-spectrum antiviral activity against certain DNA and RNA viruses in vitro, as well as moderate activity against L1210 and P388 leukemia in cell culture.
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Guanina/análogos & derivados , Guanosina/análogos & derivados , Animales , Guanina/síntesis química , Guanina/uso terapéutico , Guanosina/síntesis química , Guanosina/uso terapéutico , Leucemia L1210/tratamiento farmacológico , Leucemia P388/tratamiento farmacológico , Espectroscopía de Resonancia Magnética , Ratones , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Simplexvirus/efectos de los fármacos , Virus Vaccinia/efectos de los fármacos , Virus de la Estomatitis Vesicular Indiana/efectos de los fármacosRESUMEN
The antiviral effects of selenazofurin (2-beta-D-ribofuranosylselenazole-4-carboxamide, selenazole), ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), and 3-deazaguanosine (6-amino-1-beta-D-ribofuranosylimidazo-[4.5-C]pyridin-4(5H)-one) were investigated separately and in various combinations in an in vitro study. The combination interactions were evaluated at seven drug concentrations, graphically (isobolograms) or by using fractional inhibitory concentration indices against mumps, measles, parainfluenza virus type 3, vaccinia and herpes simplex virus type 2 viruses in Vero and HeLa cells. Selenazofurin in combination with ribavirin produced the greatest synergistic antiviral activity. However, the degree of synergy depended on the virus and cell line used. In contrast, selenazofurin combined with 3-deazaguanosine consistently yielded an indifferent or an antagonistic response, or both, whereas the ribavirin-3-deazaguanosine interaction was additive against the same viruses. Single-drug cytotoxicity was minimal for the cytostatic agents selenazofurin and ribavirin but was markedly higher for cytocidal 3-deazaguanosine, as determined by relative plating efficiency after drug exposure. The drug combinations did not significantly increase cytotoxicity (they were only additive) when used on uninfected cells. Therefore, the enhanced antiviral activities of the drug combinations (shown to be synergistic) were due to specific effects against viral replication. These results indicated that in Vero and HeLa cells (i) the combination of selenazofurin and ribavirin produced an enhanced antiviral effect, thus requiring smaller amounts of drug to cause the same antiviral effect relative to a single compound; (ii) selenazofurin when compared with ribavirin and 3-deazaguanosine appeared to have a somewhat different mode of antiviral action; (iii) 3-deazaguanosine combined with selenazofurin was an unsuitable antiviral combination; and (iv) the antiviral activity of 3-deazaguanosine appeared to be due largely to its general overall cytotoxic effect.
Asunto(s)
Antivirales/farmacología , Compuestos de Organoselenio , Ribavirina/farmacología , Ribonucleósidos/farmacología , Selenio/farmacología , ADN Viral/biosíntesis , Combinación de Medicamentos , Sinergismo Farmacológico , Guanosina/análogos & derivados , Guanosina/farmacología , ARN Viral/biosíntesisRESUMEN
A number of 3,4-disubstituted pyrazolo[3,4-d]pyrimidine ribonucleosides were synthesized and tested for their biological activity. Glycosylation of persilylated as well as nonsilylated 3-bromoallopurinol with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (4) provided the key intermediate 3-bromo-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-pyrazolo[3,4-d] pyrimidin-4(5H)-one (5a). Similar glycosylations of 3-cyanoallopurinol and 3-(methylthio)allopurinol furnished the corresponding protected N-1 glycosyl derivatives (5b and 5c). Debenzoylation of these nucleosides (5a-c) gave the corresponding 3-bromo-, 3-cyano-, and 3-(methylthio)allopurinol nucleosides (6a-c). The site of glycosylation and anomeric configuration of 6a and 6c were assigned on the basis of spectral studies as well as conversion to allopurinol ribonucleoside, whereas the structural assignment of 6b was made by single-crystal X-ray analysis. Conventional functional group transformation of 5a and 5b provided a number of novel 3-substituted allopurinol nucleosides, which included 10a and 18a-d. Glycosylation of 4-amino-3-bromopyrazolo[3,4-d]pyrimidine (14) with 4 and subsequent debenzoylation gave 3-bromo-4-aminopyrazolo[3,4-d]pyrimidine ribonucleoside (13a) from which 3,4-diamino-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidine (13b) was obtained by amination. Thiation of 5b, followed by deblocking, gave 3-cyanothiopurinol ribonucleoside (20). All of these compounds were tested in vitro against certain viruses, tumor cells, and the parasite Leishmania tropica. Among the 3-substituted allopurinol nucleosides, 18b and 18c showed significant activity against Para 3 virus and were found to be potent inhibitors of growth of L1210 and P388 leukemia. Compound 20 exhibited the most significant broad-spectrum in vitro antiviral and antitumor activity. 3-Bromoallopurinol ribonucleoside (6a) was found to be more active than allopurinol ribonucleoside against Leishmania tropica within human macrophages in vitro.
Asunto(s)
Antineoplásicos , Antivirales , Leishmaniasis/tratamiento farmacológico , Nucleósidos de Pirimidina/síntesis química , Animales , Células Cultivadas , Humanos , Ratones , Nucleósidos de Pirimidina/farmacología , RatasRESUMEN
Several pyrazolo[3,4-d]pyrimidine-4(5H)-selone ribonucleosides were prepared as potential antiparasitic agents. Treatment of 4-chloro-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)pyrazolo [3,4-d]pyrimidine (5a) with selenourea and subsequent deacetylation gave 1-beta-D-ribofuranosylpyrazolo[3,4-d] pyrimidine-4(5H)-selone (6a). A similar treatment of 3-bromo-4-chloro-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)pyrazolo [3,4-d]pyrimidine (5b) with selenurea, followed by debenzoylation, gave the 3-bromo derivative of 6a (6b). Glycosylation of persilylated 4-chloro-6-methyl-pyrazolo [3,4-d]pyrimidine (7) with tetra-O-acetylribofuranose (8) provided the key intermediate 4-chloro-6-methyl-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl) pyrazolo[3,4-d]pyrimidine (9). Ammonolysis of 9 gave 4-amino-6-methyl-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidine (10), whereas treatment with sodium hydroxide gave 6-methylallopurinol ribonucleoside (11a). Reaction of 9 with either thiourea or selenourea, followed by deacetylation, provided 6-methylpyrazolo[3,4-d]pyrimidine-4(5H)-thione ribonucleoside (11c) and the corresponding seleno derivative (11d), respectively. The structural assignment of these nucleosides was made on the basis of spectral studies. These compounds were tested in vitro against certain viruses and tumor cells. All the compounds except 11c exhibited significant activity against HSV-2 in vitro, whereas 11c exhibited the most potent activity against measles and has a very low toxicity. Compounds 6a, 6b, and 11d were found to be potent inhibitors of growth of L1210 and P388 leukemia in vitro.
Asunto(s)
Antineoplásicos/síntesis química , Antivirales/síntesis química , Nucleósidos/síntesis química , Selenio , Animales , Chlorocebus aethiops , Células HeLa , Humanos , Leucemia L1210/tratamiento farmacológico , Leucemia P388/tratamiento farmacológico , Virus del Sarampión/efectos de los fármacos , Ratones , Nucleósidos/toxicidad , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Simplexvirus/efectos de los fármacos , Ensayo de Placa ViralRESUMEN
The relative in vitro antiviral activities of three related nucleoside carboxamides, ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide), and selenazole (2-beta-D-ribofuranosylselenazole-4-carboxamide), were studied against selected DNA and RNA viruses. Although the activity of selenazole against different viruses varied, it was significantly more potent than ribavirin and tiazofurin against all tested representatives of the families Paramyxoviridae (parainfluenza virus type 3, mumps virus, measles virus), Reoviridae (reovirus type 3), Poxviridae (vaccinia virus), Herpes-viridae (herpes simplex virus types 1 and 2), Togaviridae (Venezuelan equine encephalomyelitis virus, yellow fever virus, Japanese encephalitis virus), Bunyaviridae (Rift Valley fever virus, sandfly fever virus [strain Sicilian], Korean hemorrhagic fever virus), Arenaviridae (Pichinde virus), Picornaviridae (coxsackieviruses B1 and B4, echovirus type 6, encephalomyocarditis virus), Adenoviridae (adenovirus type 2), and Rhabdoviridae (vesicular stomatitis virus). The antiviral activity of selenazole was also cell line dependent, being greatest in HeLa, Vero-76, and Vero E6 cells. Selenazole was relatively nontoxic for Vero, Vero-76, Vero E6, and HeLa cells at concentrations of up to 1,000 micrograms/ml. The relative plating efficiency at that concentration was over 90%. The effects of selenazole on viral replication were greatest when this agent was present at the time of viral infection. The removal of selenazole from the medium of infected cells did not reverse the antiviral effect against vaccinia virus, but there was a gradual resumption of viral replication in cells infected with parainfluenza type 3 or herpes simplex virus type 1 (strain KOS). However, the antiviral activity of ribavirin against the same viruses was reversible when the drug was removed.