Effects of various salts on the binding of indole compounds with bovine albumin.
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Aspartic Acid↗
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Results for “Lithium Compounds”
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Catalytic enantioselective allylation of ketoimines.
A general catalytic allylation of simple ketoimines was developed using 1 mol % of CuF.3PPh(3) as catalyst, 1.5 mol % of La(O(i)Pr)(3) as the cocatalyst, and stable and nontoxic allylboronic acid pinacol ester as the nucleophile. This reaction constituted a good template for developing the first catalytic enantioselective allylation of ketoimines. In this case, using LiO(i)Pr as the cocatalyst produced higher enantioselectivity and reactivity than La(O(i)Pr)(3). Thus, using the CuF-cyclopentyl-DuPHOS complex (10 mol %) and LiO(i)Pr (30 mol %) in the presence of (t)BuOH (1 equiv) produced high enantioselectivity up to 93% ee from a range of aromatic ketoimines. Mechanistic studies indicated that LiO(i)Pr accelerates the reaction by increasing the concentration of an active nucleophile, allylcopper.
Alkanes↗
Synthesis of (E)-alpha,beta-unsaturated amides with high selectivity by using samarium diiodide.
Stereoselective beta-elimination of 2-chloro-3-hydroxyamides 1 is achieved by using samarium diiodide to yield alpha,beta-unsaturated amides 2, in which the C=C bond is di- tri-, or tetrasubstituted. The starting compounds 1 are easily prepared by reaction of the corresponding lithium enolates of alpha-chloroamides with aldehydes or ketones at - 78 degrees C. The influence of the reaction conditions and the structure of the starting compounds on the stereoselectivity of the beta-elimination reaction is also discussed.
Journal Article↗
Synthesis of (E)-alpha,beta-unsaturated esters with total or high diastereoselectivity from alpha,beta-epoxyesters.
[reaction: see text] High stereoselective beta-elimination in 2,3-epoxyesters 1 was achieved using samarium diiodide, yielding alpha,beta-unsaturated esters 2, in which the C=C bond is di-, tri- or tetrasubstituted. The starting compounds 1 are easily prepared by reaction of the corresponding lithium enolates of alpha-chloroesters with aldehydes or ketones at -78 degrees C. The influence of the reaction conditions and the structure of the starting compounds in the stereoselectivity of the beta-elimination reaction is also discussed.
Journal Article↗
Studies of the formation of all-carbon quaternary centres, en route to lyngbyatoxin A. A comparison of phenyl and 7-substituted indole systems.
Copper mediated allylic substitutions and conjugate additions to geranyl, cinnamyl and allylic indole compounds have been investigated with the aim of finding a method for the creation of the all-carbon quaternary centre present in the natural product lyngbyatoxin A. Reaction conditions have been found giving a 68% SN2' selectivity in the copper mediated addition of PhMgBr to geranyl chloride, as well as 99% and 95% SN2' selectivity in the copper catalysed addition of EtMgBr to cinnamyl chloride and acetate, respectively. When the optimised reaction conditions were applied to the corresponding allylic compounds containing a 7-substituted indole moiety, the regioselectivity was reversed giving only the SN2 product. The allylic indole-containing substrates were also found to be unproductive in Pd- or Mo-catalysed SN2'-type substitution reactions. In related studies, copper catalysed conjugate addition of EtMgBr to the tricyclic lactam 6-methyl-pyrrolo[3,2,1-ij]quinolin-4-one gave a maximum of 20% of the 1,4-addition product.
Cinnamates↗
Formulation and in vitro-in vivo evaluation of sustained-release lithium carbonate tablets.
The release of lithium carbonate incorporated into polymethylmethacrylate, polyvinyl chloride, hydrogenated vegetable oil, and carbomer matrix tablets was studied in vitro. The formulation containing 10% carbomer showed a sustained-release profile comparable to that of a standard, commercially available, sustained-release preparation containing 400 mg lithium carbonate embedded in a composite material. In vivo the newly formulated and standard sustained-release lithium carbonate tablets were compared to an oral solution and conventional lithium carbonate tablets in 12 healthy subjects. These crossover studies showed that the sustained-release tablets produced a flatter serum concentration curve than the oral solution and conventional tablet, without loss of total bioavailability.
Adult↗
[COMPLEXOMETRIC DETERMINATION OF CALCIUM BY MEANS OF A SUBSTITUTED PHENYLAZONAPHTHALENE DISULFONIC DYE. APPLICATION TO THE MEASUREMENT OF URINARY AND FECAL CALCIUM IN MAN].
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Azo Compounds↗
Mechanism of lithium action: in vivo and in vitro effects of alkali metals on brain superoxide dismutase.
Intraperitoneal administration of lithium (2 mEq/kg/day) was found to increase the superoxide dismutase (SOD) activity in certain brain regions after 24 hours (2 injections) and 3 days (once a day) of exposure. In vitro addition of wide range of lithium (0.1 to 8 mEq) to enzyme preparation as well activated cortical SOD activity; however, at 10 mEq concentrations an inhibition was observed. The increase in SOD activity did not appear to be region specific as under both in vivo and in vitro conditions lithium enhanced enzyme activity in all the tested brain regions. The effects of intraperitoneal administration of 2 mEq/kg rubidium and cesium for 24 hr (2 injections) and 6 days (once a day) were also studied on central SOD. Both the alkali metals were not found to produce any significant alteration in the cortical enzymic activity. When the in vitro effects of these monovalent alkali metals were tested, only 2 mEq rubidium was found to increase cortical SOD; however, cesium and potassium at similar concentration did not produce any appreciable effects. It appears from the data that lithium-induced increase in brain SOD activity is not an unspecific effect of alkali metals. SOD enzyme disposes cytotoxic superoxide radicals which, if not removed, could impair the normal functioning of cellular membrane and produce a variety of psychedelic compounds as well. The activation of central SOD by lithium would enhance the disposal process of superoxide radicals whose pathological concentrations may be present in affective disorders. The mechanism of lithium-induced activation of SOD, at present, is not known.
Animals↗
Bis[mu-P,P'-methylenebis(diisopropyl phosphonate)-kappa3O,O':O]bis[chlorolithium(I)]: a centrosymmetric dimer of lithium chloride with terminal chloride anions.
The molecule of the title dimeric compound, [Li(2)Cl(2)(C(13)H(30)O(6)P(2))(2)] or [LiCl([((i)PrO)(2)P(O)](2)CH(2))](2), lies about an inversion center and features tetrahedrally coordinated Li atoms. The neutral ligands each chelate to one metal center and bridge to the other center through P=O units. Unusually for lithium chloride complexes, the Cl- ions are in terminal rather than bridging positions. Principal dimensions include Li-O(four-membered ring) = 1.959 (3) and 2.056 (3) A, Li-O(phosphonate ring) = 1.929 (3) A, and Li-Cl = 2.293 (3) A.
Journal Article↗
Preparation and EPR studies of lithium phthalocyanine radical as an oxymetric probe.
The electron paramagnetic resonance (EPR) spectrum of the paramagnetic center in solid lithium phthalocyanine, LiPc, exhibits a pO2 (partial pressure of oxygen)-dependent line width. The compound is insoluble in water and is not easily biodegradable and, therefore, is a useful spin probe for quantitative in vivo oxymetry. Because EPR spectrometry is potentially a useful technique to quantitatively obtain in vivo tissue pO2, such probes can be used to obtain physiological information. In this paper, a simple experimental procedure for the preparation of LiPc using potentiostatic electrochemical methods is described. The setup was relatively inexpensive and easy to implement. A constant potential ranging from 0.05 to 0.75 V versus Ag+/AgCl(s) was used for obtaining LiPc. The EPR spectral studies were carried out using spectrometers operating at X-band and at radiofrequency (RF) at different pO2 values to characterize the spectral response of these crystals. The results indicate that, depending on the electrolysis conditions, the products contain mixtures of crystals exhibiting pO2-sensitive and pO2-insensitive line widths. Electrolysis conditions are reported whereby the pO2-sensitive LiPc crystals were the predominant product. The influence of the working surface of the electrode and the electrolysis time on the yield were also evaluated. The crystals of LiPc were also studied using a time-domain RF EPR spectrometer. In time-domain EPR, the signals that survive beyond the spectrometer dead time are mainly the narrow lines corresponding to the pO2-sensitive crystals, whereas the signals arising from the pO2-insensitive component of LiPc were found not to survive beyond the spectrometer dead time. This signal survival makes the time-domain EPR method more sensitive for pO2 measurements using LiPc because the line width becomes very narrow at very low pO2 and, concomitantly, the relaxation time T2 longer, with no modulation or power saturation artifacts that are encountered as in the continuous wave (cw) mode. Further, minimal contributions from object motion in the spectral data obtained using time-domain methods make it an advantage for in vivo applications.
Crystallization↗
Preparation of new [1,2,4]triazolo[4,3-b]pyridazines. Part 12: Studies in the field of pyridazine compounds.
6-Substituted-[1,2,4]triazolo[4,3-b]pyridazine-3-methanol, -aldehyde, -nitrile, -chloromethyl and -aminomethyl derivatives of potential antihypertensive activity were synthesized. The reduction of methyl[1,2,4]triazolo[4,3-b] pyridazine-3-carboxylate by lithium aluminium hydride and potassium borohydride was examined. The new compounds failed to exhibit hypotensive or antihypertensive effect. Compound 2a was a minor metabolite of GYKI-11679 [7].
Animals↗
Rhamnogalacturonan II from cell walls of Cryptomeria japonica.
The pectic polysaccharides isolated from cell walls of xylem-differentiating zones of sugi (Cryptomeria japononica) were degraded with endo-alpha-(1-->4)-polygalacturonase and the polysaccharides, composed mainly of rhamnogalacturonan II (RG-II), were obtained from the degradation products. These polysaccharides consisted of rhamnosyl, fucosyl, arabinosyl, xylosyl, galactosyl, glucosyl, galacturonic acid, glucuronic acid and the characteristic sugars of RG-II, namely, 2-O-methylfucose, 2-O-methylxylose, apiose, aceric acid and thiobarbituric acid assay-positive glycosyl ¿probably, 3-deoxy-D-manno-2-octulosonic acid (Kdo) and 3-deoxy-D-lyxo-heptulosaric acid (Dha)¿. The polysaccharides contained the glycosyl residues of RG-II, besides small amounts of the glycosyl linkages of RG-I. The RG-II was structurally analysed by partial acid hydrolysis and lithium treatment in ethylenediamine. The glycosyl sequences of three compounds generated by partial hydrolysis were not identical to the partial structure of the sycamore (Acer pseudoplatanus) RG-I and RG-II structures previously proposed by Albersheim et al. Furthermore, five novel glycosyl sequences were detected in the products from lithium treatment. The results suggest that the structure of sugi RG-II is somewhat different from that of sycamore RG-II.
Carbohydrate Sequence↗
Synthesis of 11-phenyl-2,3,4,5-tetrahydro-1H-(1,4)diazepino(1,2-a)indoles and 1-(3-aminopropyl)-2-hydroxymethyl-3-phenylindoles as 5-hydroxytryptamine antagonists.
A series of novel 11-phenyl-2,3,4,5-tetrahydro-1H-(1,4)diazepino(1,2-a) indoles (5a-f) and 1-(3-aminopropyl)-2-hydroxymethyl-3-phenylindoles (6a-f) are reported. The compounds (5a-f) were prepared by the lithium aluminum hydride (LAH) reduction of corresponding 11-phenyl-1H-1-oxo-2,3,4,5-tetrahydro(1,4)diazepino(1,2-a)indoles (4a-f). The precursors (4a-f) were, in turn, prepared by the catalytic reduction of 1-(2-cyanoethyl)-3-phenylindole-2-carboxylates (2a-f) and cyclization of the resulting 1-(3-aminopropyl)-3-phenylindole-2-carboxylates (3a-f) with sodium hydride in xylene. The LAH reduction of 2a-f gave exclusively 1-(3-aminopropyl)-2-hydroxymethyl-3-phenylindoles (6a-f) and not the diazepinoindoles (5a-f) which were expected. The title compounds and the intermediates have been screened for their anti-5-hydroxytryptamine (anti-5-HT) activity. The most potent anti-5-HT compounds of this series, 6a and 6e, were found to be weak compared with cyproheptadiene, a standard anti-5-HT drug.
Animals↗
Quinazoline antifolates inhibiting thymidylate synthase: 4-thio-substituted analogues.
We report the synthesis of four new 4-thio-5,8-dideazafolic acid analogues and a 4-(methylthio) analogue structurally related to the thymidylate synthase (TS) inhibitor N10-propargyl-5,8-dideazafolic acid. Three N10-propargyl-4-thio-5,8-dideazafolic acid analogues had C2 amino, hydrogen, and methyl substituents. A 4-thio and a 4-(methylthio) compound each with hydrogen at C2 and ethyl at N10 were also synthesized. In general, the synthetic route involved thionation of the appropriate 4-oxoquinazoline; the sulfur thus introduced was then protected by methylation. Further protection with a pivaloyl group was required for the quinazoline bearing a 2-amino substituent. The protected quinazolines were treated with N-bromosuccinimide and the resulting 6-(bromomethyl) compounds were then coupled to the appropriate N-monoalkylated diethyl N-(4-aminobenzoyl)-L-glutamate in N,N-dimethylacetamide with calcium carbonate as base. The 4-thio-5,8-dideazafolic acids were obtained by removal of the methylthio group with sodium hydrosulfide, followed by deprotection of the carboxyl groups with cold dilute alkali. For the compound containing a pivaloyl protecting group, hot dilute alkali was used. To obtain the 5,8-dideazafolic acid containing a 4-(methylthio) substituent, the corresponding diester was treated with lithium hydroxide which selectively deprotected the carboxyl groups. The five compounds were tested as inhibitors of L1210 TS. It was found that replacement of the 4-oxygen of the quinazoline moiety by sulfur did not alter the TS inhibition. However, the introduction of a methylthio substituent at position 4 severely impaired TS inhibition. All 4-thio compounds were less cytotoxic to L1210 cells in culture than their 4-oxo counterparts.
Animals↗
Treatment of depressions resistant to tricyclic antidepressants, related drugs or MAO-inhibitors by lithium addition: review of the literature.
Although it might be premature to consider the efficacy of lithium addition in patients unresponsive to conventional antidepressant drug treatment as established, the evidence is suggestive. Besides 26 open studies, four out of six controlled investigations reported a positive effect of combined therapy administered in the indicated sequence. Three controlled studies confirmed the original observation of de Montigny et al. that improvement may occur within 48 hours. Successful lithium addition was reported in different types of depression and after pretreatment with tricyclic antidepressants, related compounds or MAO-inhibitors. Preliminary recommendations with respect to the practical use of lithium addition are made.
Antidepressive Agents, Tricyclic↗
MOLECULAR CHARACTERISTICS OF CANINE CARDIAC MYOSIN.
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Adenosine Triphosphatases↗
Therapeutic drug monitoring of non-anticancer drugs in cancer patients.
Therapeutic drug monitoring (TDM) or the measurement of drug concentrations in plasma, serum or blood, aims to improve clinical activity, avoid toxicity, and reduce the costs of drug treatment. Specific conditions for TDM to be reasonably applied include the availability of a validated assay, a considerable interindividual pharmacokinetic variability, a high correlation between drug concentration and toxicity, and a narrow therapeutic index. Cancer patients are especially prone to drug-drug interactions due to significant comedication, impaired liver and kidney function and hypoalbuminemia with altered drug binding. This article discusses TDM for various broadly used non-anticancer drugs in cancer patients and gives specific recommendations. Selected drugs covered in this article include those regularly used in febrile neutropenic patients such as the glycopeptide antibiotics, aminoglycosides, the antifungal agents, including flucytosine and azole compounds, the anticonvulsants phenytoin, carbamazepine and valproate, the tricyclic antidepressants, selective-serotonin-reuptake inhibitors, lithium, morphine, digitalis glycosides and the immunosupressants cyclosporin A, tacrolimus, sirolimus and mycophenolate mofetil, crucial compounds in the setting of bone marrow transplantation. In all cases, treating physicians have to consider the variability in patient age, disease stage, comedication, organ function and protein level to weigh the pros and cons of TDM in the individual cancer patient.
Aminoglycosides↗
Heavy-metal aromatic and conjugated species: rings, oligomers, and chains of tin in Li(9)(-)(x)EuSn(6+)(x), Li(9)(-)(x)CaSn(6+)(x), Li(5)Ca(7)Sn(11), Li(6)Eu(5)Sn(9), LiMgEu(2)Sn(3), and LiMgSr(2)Sn(3).
The title compounds were synthesized from the elements by heating the corresponding mixtures at high temperature. Their structures were determined from single-crystal X-ray diffraction. Li(9)(-)(x)()EuSn(6+)(x)(), Li(9)(-)(x)()CaSn(6+)(x)(), Li(5)Ca(7)Sn(11), and Li(6)Eu(5)Sn(9) contain columns of stacked aromatic pentagons of Sn(5)(6)(-) that are analogous to the cyclopentadienyl anion C(5)H(5)(-). The pentagons are separated with Ca(2+) or Eu(2+) in the columns and resemble a polymeric metallocene. In addition to the columns, the isostructural Li(9)(-)(x)()EuSn(6+)(x)() and Li(9)(-)(x)()CaSn(6+)(x)() contain isolated tin atoms and bent tin trimers while Li(5)Ca(7)Sn(11) and Li(6)Eu(5)Sn(9) contain flat zigzag hexamers and flat zigzag infinite chains of tin, respectively. The isostructural LiMgEu(2)Sn(3) and LiMgSr(2)Sn(3) do not contain columns of pentagons but only flat zigzag infinite chains of tin. The aromaticity of the pentagons and the conjugation of the pi-systems of the hexamers and the infinite chains are discussed. The title compounds are also characterized by magnetic and conductivity measurements.
Calcium↗