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1.
By using microorganisms (their esterase), (±)-trans and cis-2-methylcyclohexyl acetates were asymmetrically hydrolyzed to (?)-trans-2-methylcyc]ohexanol with (+)-trans-2-methyl-cyclohexyl acetate and (?)-cis-2-methylcyclohexanol with (+)-cis-2-methylcyclohexyl acetate. Similarly (±)-trans and cis-3-methylcyclohexyl acetates were hydrolyzed by the same microorganisms to give (+)-trans-3-methylcyclohexanol with (?)-trans-3-methylcyclohexyl acetate and (?)-cis-3-methylcyclohexanol with (+)-cis-3-methylcyclohexyl acetate.  相似文献   

2.
Cytokinin-autonomous tobacco callus was incubated in defined mineral medium containing 3H-adenine for 60 minutes. Radioactivity was incorporated into the four predominant free cytokinins, ribosyl-trans-zeatin, trans-zeatin, N6-(Δ2-isopentenyl) adenosine and N6-(Δ2-isopentenyl) adenine. The bases were more abundant than their respective ribosides, N6-(Δ2-isopentenyl) adenine being the most abundant cytokinin. No discrete peaks of radioactivity could be detected on the HPLC column eluate corresponding to the elution volumes of cis-zeatin and ribosyl-cis-zeatin.  相似文献   

3.
The main component of Japanese Ho-leaf oil has been shown to be (?)-linalool (80~90%), and the following twenty minor constituents newly have been identified; methyl vinyl ketone, methyl isobutyl ketone, mesityl oxide, β-pinene, myrcene, (+)-limonene, cis- and trans-ocimene, n-hexanol, cis-3-hexenol, cis- and trans-linalool oxide, (?)-1-terpinen-4-ol, (+)-cis and (+)-trans-2,6,6-trimethyl-2-vinyl-5-hydroxytetrahydropyran, citronellol, nerol, (+)-β-selinene, (+)-tagetonol and (?)-trans-hotrienol. (+)-Tagetonol and (?)-trans-hotrienol have been demonstrated to be (+)-3,7-dimethyl-3-hydroxy-1-octen-5-one (III) and (3R)-(?)-trans-3,7-dimethyl-3-hydroxy-1,5,7-octatriene (IX), respectively.  相似文献   

4.
The cytoplasmic and outer membranes containing either trans9-octadecenoate, trans9-hexadecenoate or cis9-octadecenoate as predominant unsaturated fatty acid residues in the phospholipids were prepared from a fatty acid auxotroph, Escherichia coli strain K1062. Order-disorder transitions of the phospholipids were revealed in both fractions of the cell envelope by fluorescent probing or wide angle X-ray diffraction. The mid-transition temperatures, Tt, and the range of the transition, ΔT, are similar in the outer and cytoplasmic membrane. Relative to the corresponding extracted lipids, 60–80% of the hydrocarbon chains take part in the transition in the cytoplasmic membrane whereas in the outer membrane only 25–40% of the chains become ordered. The results suggest that in the outer membrane part of the lipids form fluid domains in the form of mono- and/or bilayers.  相似文献   

5.
A S Bloom  C O Haavik  D Strehlow 《Life sciences》1978,23(13):1399-1404
The effect of (?)-Δ9-THC on the activities of Mg2+?, Na+?K+? and Mg2+Ca2+-ATPases were studied in mouse brain subcellular fractions. In vitrotreatment with Δ9-THC produced a dose dependent stimulation of Mg2+ ATPase in the crude mitochondrial fraction and its subfractions and a dose-related inhibition of this activity in the microsomal fraction. Na+-K+- and Mg2+-Ca2+-ATPase activities were inhibited in a dose-related manner in all subcellular fractions studied.  相似文献   

6.
The metabolism of the prostaglandin F analogues, 15-methyl-Δ4-cis-PGF and 16,16-dimethyl-Δ4-cis-PGF, has been investigated in the cynomolgus monkey and the human female. The two analogues, tritium labelled in the 9β-position, were administered by intramuscular injections into the monkeys and by subcutaneous injections into the human. Excretion of tritium labelled products were followed in urine (in both species) and feces (in monkeys only) and several metabolites were identified by GC/MS. The analogues were found to be resistant to the 15-hydroxy dehydrogenase and furthermore the degradation by β-oxidation was delayed. About 13% of the given dose of 15-methyl-Δ4-cis-PGF was excreted unchanged into urine and feces from the monkey. The corresponding figure for 16,16-dimethyl-Δ4-cis-PGF was about 20%. In addition, a large part of the metabolites had the carbon skeleton intact and were only metabolized by ω-oxidation. The relative resistance to degradation of these two analogues is likely to be the basis for their prolonged pharmacological activity.  相似文献   

7.
Compared to (+)-pseudococaine, (?)-cocaine was 20 times more potent in inhibiting uptake of 3H-norepinephrine (3HNE) by cortical synaptosomes and 66 times more potent with respect to 3H-dopamine (3HDA) uptake by striatal synaptosomes. Although the tropacocaine isomers were equipotent as inhibitors of 3HNE uptake in the cortex, tropacocaine was 3.9 times more potent as an inhibitor of 3HDa uptake in the striatum than pseudotropococaine. A major known cocaine metabolite, benzoylecgonine failed to inhibit the accumulation of 3HNE and 3HDA by synaptosomes from the cortex and striatum, respectively. The implications of these findings in relation to the motor stimulation seen with (?)-cocaine, (+)-pseudococaine and benzoylecgonine in rats are discussed.  相似文献   

8.
L(+)-threo-chloramphenicol induces reversion of His?Salmonella typhimurium strains TA100 and TA1535 in the conventional Ames' assay without microsomal activation. Any mutagenicity of D(?)-threo-chloramphenicol was masked by toxicity. Similarly, a sensitive fluctuation test showed mutagenesis with L(+)-threo-chloramphenicol at concentrations of 0.5 μM and above but the D(?) isomer proved to be toxic even at these low levels. The L(+) isomer caused single strand breaks in the DNA of Escherichia coliBr and Salmonella typhimurium strains TA1535, TA100 and TA1976. The D(?) isomer caused breaks in Escherichia coliBr and Salmonella typhimurium TA1976 although it was less effective and it did not produce DNA breaks in TA1535 or TA100.  相似文献   

9.
NMR titration curves have been recorded for all the 13C resonances of cis and transN-acetyl-dl-proline in 2H2O. the measured pK2H values are 3.4 ± 0.8 and 4.13 ± 0.08 respectively; the free energy of ionization for the trans isomer being (3.8 kJ/mole) greater than for the cis. The ionization shifts of the two isomers differ significantly only at the acetyl carbonyl and Cγ positions. It is suggested that these are related to conformational changes which stabilize the trans form at low p2H.  相似文献   

10.
Leukotriene A: stereochemistry and enzymatic conversion to leukotriene B   总被引:13,自引:0,他引:13  
Leukotriene A was assigned the structure 5(S)-trans-5,6-oxido-7,9-trans-11,14-cis-eicosatetraenoic acid by the enzymatic conversion of a synthetic product of known stereochemistry into the naturally occurring isomer of 5(S),12(R)-dihydroxy-6,8,10,14-eicosatetraenoic acid in human polymorphonuclear leukocytes.  相似文献   

11.
N-(3′,4′-Dihydroxy-trans-cinnamoyl)-3-(3,4-dihydroxyphenyl)-L-alanine [(?)-clovamide], the major phenolic metabolite (0.1%) in the bark of Dalbergia melanoxylon, is associated with minor proportions of its cis-isomer, and similar pairs of geometrical isomers of their deoxy analogues N-(4′-hydroxycinnamoyl)-3-(3,4-dihydroxyphenyl)-L-alanine and N-(4′-hydroxycinnamoyl)-3-(4-hydroxyphenyl)-L-alanine. (?)-Trans-clovamide is synthesized by direct condensation of the acid chloride of caffeic acid with L-DOPA. Diagnostic CD spectra of these compounds and 13C spectra of (?)-trans- and (?)-cis-clovamides are recorded.  相似文献   

12.
By microorganisms or esterase they produce, (±)-1 and 2-decalyl acetates were asymmetrically hydrolyzed to (?)-1-(R)-trans,cis-1-decalol (IIa), (+)-1-(S)-cis,cis-1-decalol (IIIb), (+)-1-(R)-cis,trans-1-decalol (IVa) and (+)-1-(S)-trans,trans-2-decalol (VIIb), (?)-cis,cis-2-decalol (IXb) with the acetates of their antipodes, whereas the axial acetates of (±)-decalols were scarecely hydrolyzed.  相似文献   

13.
The action of four synthetic 5(S), 12(R)-dihydroxy-6,8,10,14-eicosatetraenoic acids has been compared to the action of natural leukotriene B4 (LTB4) in perfused guinea-pig lung and in the parenchymal strip preparations. Synthetic LTB4 (Fig. 1) having the 6-cis, 8, 10-trans triene unit was found to be as powerful as natural LTB4 both for contracting the parenchymal strip and for releasing prostaglandins and thromboxanes from the perfused lung while three other isomers were inactive. The results indicate that the action of LTB4 on the lung is highly dependent on the geometry of the conjugated triene.  相似文献   

14.
A third major chemical constituent of slow reacting substance (SRS-A) has been shown to possess the chemical structure 5(S)-hydroxy-6(R)S-cysteinyl-7,9-trans-11,14-cis-eicosatetraenoic acid (leukotriene E). Comparison of the biological activities of leukotriene E and the 11-trans stereoisomer on guinea pig airways, ileum, and cutaneous microvasculature has revealed a noteworthy dependence of activity on stereochemistry with leukotriene E being much more potent in each system.  相似文献   

15.
Leukotriene C-1, a “Slow Reacting Substance” (SRS), has been shown to possess the molecular Structure depicted by V (5(S)-hydroxy-6(R)-S-glutathionyl-7,9-trans-11,14-cis-eicosatetraenoic acid) by its identity with a totally synthetic product of known structure and stereochemistry.  相似文献   

16.
A slow reacting substance, produced by murine mastocytoma cells, has been shown to have the structure 5(S)-hydroxy-6(R)-S-glutathionyl-7,9,11-trans-14-cis-eicosatetraenoic acid (11-trans leukotriene C, previously referred to as leukotriene C-2) by ultraviolet spectroscopy, amino acid analyses, lipoxygenase conversion and comparisions with a synthetic compound of known structure and stereochemistry.  相似文献   

17.
d1-Prostaglandin E1 and d1-11-deoxyprostaglandin E1 are conveniently synthesized via the copper (I) catalyzed conjugate addition of the Grignard reagent prepared from 3-trityloxy-trans-1-octenyl bromide to the appropriate cyclopentenone precursor. The Grignard reagent also afforded the synthesis of a novel structure, d1-15-hydroxy-9-oxo-13-cis-prostenoic acid.  相似文献   

18.
Marihuana and hashish are the most widely used illicit drugs. They are derived from the hemp plant, Cannabis sativa. Among the diverse chemicals in the plant, more than 20 so-called cannabinoids have been isolated and their chemical structures elucidated (1). In 1965, Mechoulam and coworkers (2,3) isolated △9- tetrahydrocannabinol (△9-THC) from cannabis extract and demonstrated that it was responsible for the psychopharmacologic effects of cannabis in animals. Later, Isbell (4) and Hollister et al. (5) confirmed these findings in man. This paper reviews the physiologic disposition of △9-THC in man; the disposition of △9-THC in animals has been reviewed elsewhere (6, 7, 8).  相似文献   

19.
Varying amounts of labeled phenylethylamine (PEA), ptyramine (TRM) and phenylacetic acid (PAAc) were recovered from rabbit brain homogenates at different intervals after the intraventricular (ivn) administration of either labeled L-phenylalanine or PEA. Previous administration of imipramine or amphetamine decreased the recoveries of PEA and PAAc. Imipramine increased the recovery of TRM, which was not affected by amphetamine. The ivn injection of TRM, 2, 5, 10 and 20 min before sacrifice resulted in the recoveries of decreasing amounts of PEA. Pretreatment of the animals with chlorpromazine, haloperidol or smaller doses of Δ9-tetrahydrocannabinol (Δ9-THC) did not affect PEA recoveries from brain homogenates, whereas amphetamine or larger Δ9-THC doses resulted in increased and decreased PEA yields, respectively.These studies further show the existence of an invivo brain metabolic pathway linking L-phenylalanine to PEA and TRM. It also shows that these pathways are modified by a number of centrally active drugs.  相似文献   

20.
An unstable epoxide, leukotriene A4 (5(S)-trans-5,6-oxido-7,9-trans-11,14-cis-eicosatetraenoic acid), was earlier proposed to be an intermediate in the conversion of arachidonic acid into the slow reacting substance (SRS), leukotriene C4. In the present work synthetic leukotriene A4 was incubated with human leukocytes or murine mastocytoma cells. A lipoxygenase inhibitor, BW755C, was added in order to prevent leukotriene formation from endogenous substrate. Leukotriene C4 and 11-trans-leukotriene C4 were the main products with SRS activity. It was not established whether the 11-trans-compound was formed by isomerization at the leukotriene A4 or C4 stage.  相似文献   

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