The synthesis and nicotinic binding activity of (+/-)-epiquinamide and (+/-)-C(1)-epiepiquinamide

The synthesis of (+/-)-epiquinamide 1 and (+/-)-C(1)-epiepiquinamide 2 based on the use of a Curtius rearrangement to introduce the C(1) amino residue is reported. In a competition binding assay for [(3)H]epibatidine binding to rat brain membranes neither (+/-)-1 nor (+/-)-2 showed any significant level of nicotinic activity.     

Beta-adrenergic activity of (+/-)-hydroxybenzylisoproterenol in isolated rat fat cells and hepatocytes

The pharmacology of (+/-)-hydroxybenzylisoproterenol with respect to stimulation of cyclic AMP accumulation by isolated rat fat cells and liver cells was examined. (+/-)-Hydroxybenzylisoproterenol was found to be a full agonist and twice as potent as (-)-isoproterenol in liver cells, and equipotent to (-)-isoproterenol in fat cells with regard to stimulating cyclic AMP accumulation. A study of the ability of this catecholamine to stimulate adenylate cyclase activity of broken-cell preparations revealed that (+/-)-hydroxybenzylisoproterenol was equipotent to (-)-isoproterenol in liver cell homogenates, while 3- to 4-fold more potent than (-)-isoproterenol in fat cell ghost membranes. (+/-)-Hydroxybenzylisoproterenol was also found to be as potent as (-)-isoproterenol in stimulating cyclase activity of S49 mouse lymphoma cell membranes. Competition studies of specific [125I]iodohydroxybenzylpindolol binding to liver cell membranes revealed a Kd of 10 nM for (+/-)-hydroxybenzylisoproterenol and 25 nM for (-)-isoproterenol binding to the liver beta-adrenergic receptor. Competition studies of specific (-)-[3H]dihydroalprenolol binding to fat cell membranes indicated a similar affinity of these sites for both (+/-)-hydroxybenzylisoproterenol and (-)-isoproterenol. The guanyl nucleotide Gpp(NH)p induced a shift in the curve for competition of (-)-[3H]dihydroalprenolol binding by (-)-isoproterenol to the right, but failed to do so when (+/-)-hydroxybenzylisoproterenol was the competing agonist. Properties of (+/-)-[3H]hydroxybenzylisoproterenol binding to fat cell or liver cell membranes were inconsistent with those expected of adenylate cyclase coupled beta-adrenergic receptors.     

Incorporation of (2-3H)glycerol into rat brain 1,2-diacyl-sn-glycero-3-phosphorylcholine and 1,2-diacyl-sn-glycerol molecular species in vivo

Rat brain 1,2-diacyl-sn-glycerols (diglycerides) and 1,2-diacyl-sn-glycerols obtained from 1,2-diacyl-sn-glycero-3-phosphorylcholine after treatment with phospholipase C differ markedly in carbon number distribution. 70% of the 1,2-diacyl-sn-glycerols had a total of 38 fatty acid carbon atoms, and there was no detectable change in the 1,2-diacyl-sn-glycerol mass pattern between 7 and 23 days of age. In contrast, 1,2-diacyl-sn-glycero-3-phosphorylcholine contained at most 10% of this molecular species in the brains of rats of comparable age. A small increase in the C(36) species of 1,2-diacyl-sn-glycero-3-phosphorylcholine, which is associated with myelination, was noted between 10 and 17 days. The incorporation of intracranially injected [2-(3)H]glycerol into 1,2-diacyl-sn-glycero-3-phosphoryl-choline species with polyunsaturated fatty acids containing 20 or 22 carbon atoms was greater than into the species containing only saturated and/or monoenoic fatty acids between 30 min and 24 hr. The 1,2-diacyl-sn-glycerol fractions containing polyunsaturated fatty acids had the lowest specific activity at 30 min. The specific activity of the particular 1,2-diacyl-sn-glycerol fraction containing the stearate-arachidonate pair is the lowest for 4 hr after intracranial injection of the isotope. Thus, molecular species of 1,2-diacyl-sn-glycerol and 1,2-diacyl-sn-glycero-3-phosphorylcholine differed considerably in their labeling patterns, and a direct precursor-product relationship could not be demonstrated during the time period studied.     

Novel proteoglycan linkage tetrasaccharides of human urinary soluble thrombomodulin, SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1-4Xyl

O-linked sugar chains with xylose as a reducing end linked to human urinary soluble thrombomodulin were studied. Sugar chains were liberated by hydrazinolysis followed by N-acetylation and tagged with 2-aminopyridine. Two fractions containing pyridylaminated Xyl as a reducing end were collected. Their structures were determined by partial acid hydrolysis, two-dimensional sugar mapping combined with exoglycosidase digestions, methylation analysis, mass spectrometry, and NMR as SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1+ ++-4Xyl. These sugar chains could bind to an HNK-1 monoclonal antibody. This is believed to be the first example of a proteoglycan linkage tetrasaccharide with glucuronic acid 3-sulfate and sialic acid.     

Microbial hydroxylation of (+/-)- and (-)-(2Z,4E)-5-(1',2'-epoxy-2',6',6'-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid into (+/-)- and (-)-xanthoxin acid by Cunninghamella echinulata

Microbial hydroxylation of (+/-)-(2Z,4E)-5-(1',2'-epoxy-2',6',6'-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid (3a) with Cercospora cruenta, a fungus producing (+)-abscisic acid, gave a four-stereoisomeric mixture consisting of (+)- and (-)-xanthoxin acid (4a), and (+)- and (-)-epi-xanthoxin acid (5a) by an HPLC analysis with a chiral column. Screening of the microorganisms capable of oxidizing (+/-)-3a showed that Cunninghamella echinulata stereoselectively oxidized (+/-)-3a to xanthoxin acid (4a) with the some degree of enantioselectivity as (-)-3a to (-)-4a.     

Effect of intravenous infusion of (+/-)-noradrenaline on the urinary clearance of H3 (+/-)-noradrenaline]

In anesthetized dog, intravenous infusion of NA does not modify the relationship between [3H]-(+/-)-NA urinary clearance/GFR. Urinary excretion of NA is directly related to glomerular ultrafiltration.     

Novel lipase-catalysed enantioselective deacetylation of (+/-)-5-acetoxy-3-(4-fluorophenyl)-2-phenylisoxazolidine

(+/-)-5-Acetoxy-3-(4-fluorophenyl)-2-phenylisoxazolidine has been synthesised by a highly diastereoselective [3+2] cycloaddition reaction between alpha-(4-fluorophenyl)-N-phenylnitrone and vinyl acetate in good yield. Candida rugosa lipase catalyses the deacetylation of this (+/-)-5-acetoxyisoxazolidine in a highly enantioselective fashion in diisopropyl ether containing n-butanol affording (-)-5-acetoxy-3-(4-fluorophenyl)-2-phenylisoxazolidine in 43% yield and >99% ee.     

Solid and solution state conformations of (+/-)-3-O-acetyl-1,2:4,5-di-O-isopropylidene-allo-inositol and (+/-)-3-O-acetyl-1,2:4,5-di-O-isopropylidene-6-O-methyl-allo-inositol

The synthesis and conformational studies of (+/-)-3-O-acetyl-1,2:4,5-di-O-isopropylidene-allo-inositol and (+/-)-3-O-acetyl-1,2:4,5-di-O-isopropylidene-6-O-methyl-allo-inositol are described. Solid state conformations of the title compounds have been studied by solving their X-ray crystal structures. The inositol ring in both the compounds deviate considerably from the ideal chair conformation to flattened chair conformation in the solid state. Their conformations in solution were studied by the use of 1H NMR spectroscopy. These conformational analyses revealed that the title compounds adopt similar conformations in solid and solution states irrespective of the solvent polarity.     

alpha,beta-Dibenzyl-gamma-butyrolactone lignan alcohols: total synthesis of (+/-)-7'-hydroxyenterolactone, (+/-)-7'-hydroxymatairesinol and (+/-)-8-hydroxyenterolactone

Two trans-alpha,beta-dibenzyl-gamma-butyrolactone lignans carrying a hydroxyl group at the beta-benzylic carbon atom and a alpha-hydroxy alpha,beta-dibenzyl-gamma-butyrolactone lignan were synthesized in racemic form using the tandem conjugate addition reaction to construct the basic lignan skeleton. Subsequent reaction steps involved either a catalytic reduction of the regenerated keto group to the alcohol, or a hydrogenolysis to benzylic methylene followed by lactone enolate formation and oxidation to give the alpha-hydroxybutyrolactones. These procedures were applied for the synthesis of 7'-hydroxyenterolactones and 7'-hydroxymatairesinols, and 8-hydroxyenterolactones, respectively. The diastereomeric mixtures of these compounds were separated either by HPLC techniques or column chromatography and the structures were elucidated using NMR spectroscopy.     

Synthesis and antitumor activity of 1-mesityl-3-(2-naphthoylmethano)-1H-imidazolium bromide

An imidazolium salt, 1-mesityl-3-(2-naphthoylmethano)-1H-imidazolium bromide (MNIB), has been investigated for its antitumor properties. In vitro studies demonstrate that MNIB is active against K562, SMMC-7721, EJ, AGZY, HEP-2, A549, HepG2, and Raji tumor cells, and can induce the G1 phase cell cycle arrest and apoptosis in K562 cells. Moreover, administration of MNIB significantly inhibited tumor growth in human non-small lung tumor (A549) xenografts.     

(+/-)-2-(3-Piperidyl)-1,2,3,4-tetrahydroisoquinolines as a new class of specific bradycardic agents

A series of (+/-)-2-(3-piperidyl)-1,2,3,4-tetrahydroisoquinolines were prepared and their bradycardic activities were examined in isolated guinea-pigs' right atria and in anesthetized rats. Modifications on the benzyl moiety of the parent compound, 1, led to the identification of compound 11e as a potent and specific bradycardic agent.     

Effect of 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine inhibitor on the reduction of one-kidney, one clip hypertension after unclipping in the rat

The role of 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine in regulating blood pressure was studied in one-kidney, one clip hypertensive rats using 3-(N-n-octadecylcarbamoyloxy)-2-methoxypropyl-2-thiazolio ethylphosphate, which specifically inhibited the hypotensive activity of exogenously injected 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine. The blood pressure of rats with established hypertension produced by clipping one renal artery and contralateral nephrectomy normally decreases rapidly after unclipping the artery, but this rapid decrease was significantly inhibited by intravenous infusion of 3-(N-n-octadecylcarbamoyloxy)-2-methoxypropyl-2-thiazolio ethylphosphate. This shows that endogenous 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine participates in the rapid decrease of blood pressure after unclipping the kidney in one-kidney, one clip hypertensive rats.     

Crystal structure and anticonvulsant activity of (+/-)-1,2:4,5-di-O-isopropylidene-3,6-di-O-(2-propylpentanoyl)-myo-inositol

The biological activity and crystal structure of (+/-)-1,2:4,5-di-O-isopropylidene-3,6-di-O-(2-propylpentanoyl)-myo-inositol have been investigated. This compound shows better anticonvulsant activity than valproic acid (VPA) in the MES test as measured in mice. Its structure, determined from single-crystal X-ray diffraction measurements, shows that the inositol ring deviates from the ideal chair conformation and that the two 2-propylpentanoyl groups are located on opposite ring positions. This molecular conformation lets carbonyl and hydroxyl oxygen atoms to be available for hydrogen-bonding interactions, hinders carbonyl carbon atoms, preventing metabolic enzymatic hydrolysis, and helps to rationalize the observed inactive profile in the PTZ test. The anticonvulsant activity profile suggests a mechanism different from that of VPA.     

Structural properties of a monobrominated analog of 1, 2-dipalmitoyl-sn-glycero-3-phosphorylcholine

Hydrated multibilayers of 1-palmitoyl-2-monobromopalmitoyl-sn-glycero-3-phosphorylcholine (BrDPPC), where the 2-chain is brominated at either the C-9 or C-10 position, have been studied by low and wide angle X-ray diffraction methods. Oriented and unoriented samples were investigated. The long spacing was observed over the temperature interval -15 degrees C to 80 degrees C. A monotonic increase from approx. 50 A to approx. 62 A (28 wt. % H2O) occurred with decreasing temperature. The BrDPPC showed no evidence of a sharp gel-to-liquid crystal phase transition. Wide angle scattering showed a diffuse peak corresponding to (4.5 A)-1. Differential scanning calorimetry measurements for hydrated liposomes (50 wt. % H2O) also showed no evidence for a phase transition (-40 less than or equal to T less than or equal to 60 degrees C). These results suggest a low temperature amorphous (glass) state for the acyl side chains of BrDPPC. Monolayer film properties of monobrominated stearic acid also reflect a chain disordering effect occurring upon midchain substitution.