Degradation of 3-(3′,5′ -Dichlorophenyl)-5,5-dimethyloxazolidine-2,4-dione by Plants,Soil and Light

Studies on uptake, tissue distribution, and metabolsim of 3-(3′,5′ -dichlorophenyl)-5,5-dimethyloxazolidine-2,4-dione (DDOD) by bean and grape plants, and degradation by soil and light were carried out using ¹⁴C- or ³H-DDOD. DDOD injected at stem or absorbed through roots of bean plants was transported mainly to leaf tissues. No downward movement of the label was observed. DDOD was decomposed in the nutrient solution to N-3,5-dichlorophenyl-N-α-hydroxyisobutyryl carbamic acid (DHCA) and α-hydroxyisobutyryl-3,5-dichloroanilide (HDA). Metabolism of DDOD in bean plants or on grape berries themselves occurred to only a small extent if at all. When injected into grape trees, DDOD underwent some degree of metabolization to HDA and, probably, 3-(3′,5′ -dichloro-4′ -hydroxyphenyl)-5,5-dimethyloxazolidine-2,4-dione. In soil, DDOD broke down to DHCA, HDA, and 3,5-dichloroaniline, but formation of tetrachloroazobenzene was not observed under the present experimental conditions. DDOD decomposed to some degree when irradiated with a xenon lamp.     

Metabolism of N-(3′,5′-Dichlorophenyl)succinimide in Rats and Dogs

When N-(3′,5′-dichlorophenyl)succinimide (DSI)-carbonyI-¹⁴C and –pheny-³H were each orally administered to rats, regardless of the label site, most of the dose was readily eliminated. There was no difference in the excretion rate between male and female rats. No radioactive residues were detected in tissues and organs 24 hr after dosing. Urinary metabolites consisted of N-(3′,5′-dichlorophenyl) succinamic acid (DSA), N-(3′,5′-dichlorophe-nyl) malonamic acid (DMA), N-(3′5’-dichlorophenyl)-2-hydroxysuccinamic acid (2-OH-DSA) and 2-OH-DSA derivatives. In dogs, most of the administered dose was excreted in equal amounts in urine and feces. 2-OH-DSA derivatives were main urinary metabolites and most of fecal radiocarbon was due to intact DSL. The results of this study indicate that DSI is a biodegradable compound which is unlikely to leave any persistent residues in animals.

The degradation of DSI to DSA was mediated by an arylamidase-type hydrolase, which was present in the microsomal fraction of rabbit liver. The enzyme activity was found in livers and kidneys of four animal species tested. Depending on the animal species, the enzyme appears to be important for the metabolism of DSI.     

Synthesis and Antiviral Activity Assay of Novel (E)-3′,5′-Diamino-5-(2-bromovinyl)-2′,3′,5′-trideoxyuridine

Abstract

(E)-3′,5′-diamino-5-(2-bromovinyl)-2′,3′,5′-trideoxyuridine (5), the diamino analogue of BVDU (1), was synthesized from BVDU. In contrast with BVDU, compound 5 did not show activity against herpes simplex virus or varicella-zoster virus.     

Oligomerizations of deoxyadenosine bis-phosphates and of their 3′-5′, 3′-3′, and 5′-5′ dimers: Effects of a pyrophosphate-linked,poly(t) analog

A pyrophosphate-linked polynucleotide analog based on thymidine 3,5 bis-phosphate (pTp) catalyzes the oligomerization of activated dimers of pdAp in the presence of MgCl₂. Although no catalysis of the oligomerization of the activated monomer (ImpdAplm) was observed in the presence of MgCl₂, there was a significant stimulation of oligomerization by the template in the presence of MnCl₂.     

Synthesis of (±)-Methyl 5-(1′,2′-Epoxy-2′,6′-dimethylcyclohexyl)-3-methyl-(2Z,4E)-2,4-pentadienoate

The effect of tripropyltin chloride (TPT) on transport systems in E. coli was investigated. The inhibition on uptakes of ¹⁴C-l-leucine, l-proline, adenine and methyl-(α-d-gluco)pyrano-side (α-methylglucoside) by TPT was examined. The active uptake of l-leucine which utilized ATP molecule as an energy source was 100% inhibited at the concentration of 10 µg/ml TPT. On the other hand, the uptake of l-proline which was generated by an “energied” membrane state of the cells was inhibited only 40% at the same concentration of TPT. α-Methylglucoside uptake was scarcely inhibited. Adenine uptake was intensely inhibited at 20 µg/ml TPT. The effect of the delayed addition of TPT on transport systems was also examined. l-Leucine incorporated into cells was completely released from cells by TPT. Leucine binding protein (LBP) was prepared from E. coli cells and the effect of TPT on LBP activity was examined. TPT scarcely inhibited LBP activity.     

5,5′-dimethyloxazolidine-2,4-dione is a strong inducer of differentiation of human promyelocytic leukemia (HL-60) cells

5,5′-Dimethyloxazolidine-2,4-dione (DMO), a weak non-metabolizable acid, is commonly utilized for determining intracellular pH. In these studies, DMO was tested as an inducer of differentiation on the basis that its uptake and subsequent dissociation might transiently raise intracellular pH and activate ion-fluxes critical for triggering maturation. After 5 days of exposure to 40 mM DMO, >60% of HL-60 cells displayed phenotypic and functional changes characteristic of mature granulocytes. As with other inducers of HL-60 cell differentiation, commitment to differentiation required culture in the presence of DMO for more than 24 h, indicating that if transient effects on pH or ion-fluxes occurred, they were not sufficient to trigger this process.DMO was either weak or inactive as an inducer of murine erythroleukemia cell (FLC) differentiation. Although other weak acids and bases triggered differentiation of both HL-60 cells and FLC, the spectrum of response differed markedly between the two lines. These results suggest that: (1) a number of common buffering agents have the potential to alter cell phenotype, and (2) their effects must be evaluated for each individual cell type.     

Improved Synthesis of Adenosine Cyclic 3′, 5′-Phosphoramidates via Anhydrides. Preparation of Adenosine Cylic 3′, 5′-(Rp) - and (p)-N-Methylphosphoramidate

Abstract

The two-step method for the preparation of adenosine cyclic 3′,5′-phosphoramidate diastereoisomers, which involves the activation of adenosine cyclic 3′,5′-monophosphate (1) with an acid chloride and in situ aminolysis of the anhydride intermediate (Bentrude, W.G.; Tomsaz, J. Synthesis 1984, 27; Bottka, S.; Tomasz, J. Tetrahedron Lett. 1985, 24, 2909), has been improved. The best yields were attained when 1 was reacted with 4.4 molar equivalents of phosphorus oxychloride in trimethyl phosphate at O°C for 3 h, and the solution of phosphorus oxychloride in trimethyl phosphate was pretreated with 0.5 molar equivalent of water at room temperature for 20 min. R _p and S _p diastereoisomers of adenosine cyclic 3′,5′-N-methyphosphoramidate and N,N-dimethylphosphoramidate have been synthesized under these experimental conditions.     

Solution and Solid State Structure of 2′,5′-BIS-(O-Trityl)-3′-Oximinouridine

Abstract

Comparison of the solution (in CDCl₃ at 500 MHz¹H NMR) and X-ray crystal studies of 3′-oximinouridine 1 shows in general good agreement with the high anti glycosidic angle and in the conformation about C4′-C5′. The sugar pucker (C2′-endo) is qualititatively identical in both cases. This is the first example of a conformationally sugar-rigid nucleoside in which the rigidity arises from the sp² character of an endocyclic carbon (i.e. C3′), not from the strain due to the ring fusion (see ref. 7 for conformationally strained nucleosides).     

3′-3′,3′-5′ and 5′-5′ TpT-Amides: Synthesis,Characterization and Alkaline Hydrolysis

Abstract

A simple procedure is described for the preparation of the title compounds 1, 8 and 9. 3′-3′ or 3′-5′ or 5′-5′ TpT was reacted with a twofold molar excess of TPS in anhydrous DMF, at room temperature, for 5 min, followed by a 1 min in situ treatment of the reaction mixture with excess 7.0 N NH₄OH, at 0°C. The alkaline hydrolysis of 1, 8 and 9 proceeds without the assistance of 3′- and 5′-hydroxyl groups resulting in equimolar mixtures of thymidine (4) and thymidine 3′-phosphoramidate (6) (for the 3′-3′ isomer) or thymidine 5′-phosphoramidate (7) (for the 5′-5′ isomer) or 6 and 7 in equal quantities (for the 3′-5′ isomer).     

Flexibility of 3′,5′ Deoxyribonucleooside Diphosphates

Abstract

In 3′,5′ deoxyribonucleoside diphosphates, in addition to the nature of the base and the sugar puckering, there are six single bond rotations. However, from the analysis of crystal structure data on the constituents of nucleic acids, only three rotational angles, that are about glycosyl bond, about C4′-C5′ and about C3′-O3′ bonds, are flexible. For a given sugar puckering and a base, potential energy calculations using non-bonded, electrostatic and torsional functions were carried out by varying the three torsion angles. The energies are represented as isopotential energy surfaces. Since the availability of the real-time color graphics, it is possible to analyse these isopotential energy surfaces. The calculations were carried out for C3′ exo and C3′ endo puckerings for deoxyribose and also for four bases. These calculations throw more light not only on the allowed regions for the three rotational angles but also on the relationships among them. The dependence of base and the puckering of the sugar on these rotational angles and thereby the flexibility of the 3′,5′ deoxyribonucleoside diphosphates is discussed. From our calculations, it is now possible to follow minimum energy path for interconversion among various conformers.     

Synthesis and plant growth inhibitory activities of (+)- and (−)-(2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid

Chiral (+)- and (?)-enantiomers of (2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid have been synthesized from the chiral epoxy alcohols (+)- and (?)-1′,2′-dihydro-1′,2′-epoxy-β-ionone, which were prepared by Katsuki-Sharpless' asymmetric epoxidation of β-cyclogeraniol. The (+)-enantiomer showed strong inhibitory activity in a rice seedling and lettuce germination assay, whereas the (?)-enantiomer was 10³-times less active.     

Structure of 2′,3′-0-Isopropylidene-5-Bromouridine

Abstract

The crystal and molecular structure of the title compound has been determined by the X-ray diffraction method. The crystals are orthorhombic, space group P2₁2₁2₁ (Z=4), with the unit cell dimensions a=5.244(2), b=14.916(6) and c=19.068(5) A. The structure was solved by direct methods and refined up to the R value of 0.058 by the full matrix least-squares method. The glycosidic torsion angle is 13.5(11)° (anti conformation), the sugar puckering being C(3′)-exo, C(4′)-endo. The orientation of the C(5′)-0(5′) bond is gauche-gauche.     

Phosphonoformate Esters of Anti-HIV Nucleosides: 3′-Azido-3′-deoxythymidine and 2′,3′-Dideoxycytidine Derivatives Containing a Small 5′-(0-Alkoxycarbon-ylphosphinyl) or 5′-(O-Cholesterylcarbonylphosphinyl) Substituent

Abstract

A convenient general method of synthesis of 5′-O-(alkoxycarbonyl)phosphonate esters of 2′,3′-dideoxyribonucleosides is presented, using the 5′-O-(methoxycarbonyl)phosphinyl, 5′-0-(ethoxycarbonyl)phosphinyl, and 5′-O-(cholesterylcarbonyl)phosphinyl derivatives of 3′-azido-3′-deoxythymidine (AZT) and the 5′-0-(ethoxycarbonyl)phosphinyl derivative of 2′,3′-dideoxycytidine (ddC) as examples. Reaction of trimethyl phosphonoformate, methyl phosphonoformate, or dimethyl cholesterylcarbonylphosphonate with phosphorus pentachloride in carbon tetrachloride, followed by direct condensation of the resulting phosphonyl chloride with the nucleoside, gave the fully esterified phosphonoformate derivatives, which on treatment with sodium iodide in tetrahydrofuran underwent selective cleavage of the P-OMe or P-OEt groups, leaving the carboxylate esters intact. The resulting products were converted from sodium salts to ammonium salts by ion-exchange chromatography.     

A Direct and Efficient Synthesis of 5′-Deoxy-2′, 3′-

Abstract

A direct and efficient synthesis of 5′-deoxy-2′,3′-O-isopropylideneinosine, 7, from readily available inosine is described. An example of a potentially general synthesis of N -substituted-5′-deoxyadenosines from 7 is also described.     

Toxicological Profile of Ultrapure 2,2′,3,4,4′,5,5′-Heptachlorbiphenyl (PCB 180) in Adult Rats

PCB 180 is a persistent non-dioxin-like polychlorinated biphenyl (NDL-PCB) abundantly present in food and the environment. Risk characterization of NDL-PCBs is confounded by the presence of highly potent dioxin-like impurities. We used ultrapure PCB 180 to characterize its toxicity profile in a 28-day repeat dose toxicity study in young adult rats extended to cover endocrine and behavioral effects. Using a loading dose/maintenance dose regimen, groups of 5 males and 5 females were given total doses of 0, 3, 10, 30, 100, 300, 1000 or 1700 mg PCB 180/kg body weight by gavage. Dose-responses were analyzed using benchmark dose modeling based on dose and adipose tissue PCB concentrations. Body weight gain was retarded at 1700 mg/kg during loading dosing, but recovered thereafter. The most sensitive endpoint of toxicity that was used for risk characterization was altered open field behavior in females; i.e. increased activity and distance moved in the inner zone of an open field suggesting altered emotional responses to unfamiliar environment and impaired behavioral inhibition. Other dose-dependent changes included decreased serum thyroid hormones with associated histopathological changes, altered tissue retinoid levels, decreased hematocrit and hemoglobin, decreased follicle stimulating hormone and luteinizing hormone levels in males and increased expression of DNA damage markers in liver of females. Dose-dependent hypertrophy of zona fasciculata cells was observed in adrenals suggesting activation of cortex. There were gender differences in sensitivity and toxicity profiles were partly different in males and females. PCB 180 adipose tissue concentrations were clearly above the general human population levels, but close to the levels in highly exposed populations. The results demonstrate a distinct toxicological profile of PCB 180 with lack of dioxin-like properties required for assignment of WHO toxic equivalency factor. However, PCB 180 shares several toxicological targets with dioxin-like compounds emphasizing the potential for interactions.     

Intramolecular Radical Reactions of 5′-O-Modified 2′,3′-Didehydro-2′,3′-Dideoxyuridine Derivatives

Abstract

Radical reactions of 5′-O-(2-bromo-1-methoxy)ethyl- and 5′-O-(2-propynyl)-2′,3′-dideoxy-2′,3′-didehydrouridines were investigated. Both reactions proceeded in a 6-exo-trig manner to give products cyclized regio- and stereospecifically at the 3′-position. The structures of these products were analyzed by X-ray crystallography.

     

Effects of 3′-C-Methylation on the Hydrolytic Stability and Hydroxyl pK a Values of Dinucleoside 2′,5′- and 3′,5′-Monophosphates

Abstract

The first-order rate constants for hydrolysis of 3′-C-methyluridylyl(2′,5′)- and -(3′,5′)adenosine and the corresponding native dinucleoside monophosphates (2′,5′- and 3′,5′-UpA) have been determined as a function of hydroxide-ion concentration (0.025 - 7 M) at 25°C. In addition to the effects on the hydrolytic stability of the compounds, the effects of the 3′-C-methyl substitution on the kinetically determined pK _a values for the sugar hydroxyls of the undine moiety are discussed.