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1.
(±)-Homosarkomycin (2) and (±)-rosaprostol (3) were synthesized from (±)-methyl 2-oxo-bicyclo[3.1.0]hexane-1-carboxylate (1) by using the nucleophilic ring opening reaction on the double-activated cyclopropane ring as the key step.  相似文献   

2.
(±)-Lamprolobine, the (+)-enatiomer of which was isolated from the leaves of Lamprolobium fruticosum, and (±)-epilamprolobine were synthesized from δ-valerolactam.  相似文献   

3.
Boron is an essential nutrient for plants, but it is toxic in excess. Transgenic rice plants expressing an Arabidopsis thaliana borate efflux transporter gene, AtBOR4, at a low level exhibited increased tolerance to excess boron. Those lines with high levels of expression exhibited reduced growth. These findings suggest a potential of the borate transporter BOR4 for the generation of high-boron tolerant rice.  相似文献   

4.
A novel synthesis of ( ± )-methyl epijasomonate (2) and the first synthesis of ( ± )-methyl cucurbate (4) were achieved starting from 2-allylcyclohexane-1,3-dione (8). The synthetic epimer 2 had a stronger jasmin flavor than the trans-isomer 1 with 95% purity.  相似文献   

5.
The racemic total synthesis of elegansidiol, farnesiferol B, and farnesiferol D has been obtained following a Diels–Alder approach. Gillman addition, cross metathesis reaction are the other key steps involved in the target synthesis.  相似文献   

6.
Synthesis of (±)-phyllostine, (±)-epoxydon, (±)-epiepoxydon, (±)-epoformin and (±)-epiepoformin by the retro-Diels—Alder reaction was described.  相似文献   

7.
Protective group-free syntheses of four racemic pheromones with a 6,8-dioxabicyclo[3.2.1]octane ring were achieved in five or six steps from commercially available (±)-3-butyn-2-ol (6) and 2-alkenyl halides or 2-alken-1-ol by employing Lewis acid-catalyzed acetalization of δ, ε-epoxy ketones as the key reaction. (±)-Frontalin (1) was prepared in a 25% overall yield in five steps from methallyl chloride (5a), (±)-endo-brevicomin (2) was prepared in a 23% overall yield in five steps from (E)-2-pentenyl bromide (5b), and (±)-exo-brevicomin (3) and (±)-3,4-dehydro-exo-brevicomin (4) were both prepared in a 4% overall yield in six steps based on (Z)-2-penten-1-ol (12).  相似文献   

8.
Protective group-free syntheses of four racemic pheromones with a 6,8-dioxabicyclo[3.2.1]octane ring were achieved in five or six steps from commercially available (±)-3-butyn-2-ol (6) and 2-alkenyl halides or 2-alken-1-ol by employing Lewis acid-catalyzed acetalization of δ, ε-epoxy ketones as the key reaction. (±)-Frontalin (1) was prepared in a 25% overall yield in five steps from methallyl chloride (5a), (±)-endo-brevicomin (2) was prepared in a 23% overall yield in five steps from (E)-2-pentenyl bromide (5b), and (±)-exo-brevicomin (3) and (±)-3,4-dehydro-exo-brevicomin (4) were both prepared in a 4% overall yield in six steps based on (Z)-2-penten-1-ol (12).  相似文献   

9.
(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture of both compounds was more effective than each one individually. Helminthosporium species were again the most resistant toward the mixture. The effect of both alkaloids independently on germination and development of E. pisi conidia on excised pea leaves was also shown. After pre-inoculation with (+/-)-alpha-hydrastine, the effect was more pronounced than the addition post-inoculation; maximum inhibition occurred at 200 ppm. (+/-)-beta-Hydrastine also reduced germination of conidia but was less effective than (+/-)-alpha-hydrastine. The number of primary and secondary branches of conidia and number of appressoria were not affected significantly by either compound.  相似文献   

10.
Phosphodiesterase production with bis-p-nitrophenyl phosphate as a substrate by alkalophilic Bacillus No. A-40-2 increased with increasing Mn2+ concentration, showing maximum productivity at 10 mm. The enzyme production was negligible in the medium without Mn2+. The simultaneous addition of 10 mm Mn2+ and one of the several cations Mg2+, Co2+, Mo6+, and Pb2+ at suitable concentrations stimulated the enzyme production 1.8-fold at most over that with only 10 mm Mn2+. Inorganic phosphate hardly repressed the enzyme production. The enzyme was purified homogeneously. The purified enzyme had the optimum pH of 7.5 and was fairly stable from pH 7–11. The enzyme hydrolyzed 2′,3′-cyclic-nucleotides and 3′-nucleotides, but did not hydrolyze 3′,5′-cyclic-nucleotides or 5′-nucleotides, indicating it to be a 2′,3′-cyclic-nucleotide 2′-phosphodiesterase (EC 3.1.4.16). The enzyme had activity without metals, but Mg2+, Ca2+, Ba2+, and Mo6+ activated the enzyme reaction.  相似文献   

11.
(±)-Licarin A (1) was obtained by oxidative coupling, and its enantiomers, (?)-licarin A (2) and (+)-licarin A (3), were resolved by chiral HPLC. Schistosomicidal and trypanocidal activities of these compounds were evaluated in vitro against Schistosoma mansoni adult worms and trypomastigote forms of Trypanosoma cruzi. The racemic mixture (1) displayed significant schistosomicidal activity with an LC50 value of 53.57 μM and moderate trypanocidal activity with an IC50 value of 127.17 μM. On the other hand, the (?)-enantiomer (2), displaying a LC50 value of 91.71 μM, was more active against S. mansoni than the (+)-enantiomer (3), which did not show activity. For the trypanocidal assay, enantiomer 2 showed more significant activity (IC50 of 23.46 μM) than enantiomer 3, which showed an IC50 value of 87.73 μM. Therefore, these results suggest that (±)-licarin A (1) and (?)-licarin A (2) are promising compounds that could be used for the development of schistosomicidal and trypanocidal agents.  相似文献   

12.
Dimethyl ethers of (±)-hinokiresinol, dihydro- and tetrahydro-hinokiresinol have been synthesized. The key compounds, 1,3-bis-(p-methoxyphenyl)-pentan-1-one (4) and 1,3-bis-(p-methoxyphenyl)-4-penten-1-one (8) were obtained by treatment of 4,4′-dimethoxybenzal-acetophenone (3) with ethyl magnesium iodide and vinyl magnesium chloride, respectively. On Clemmensen reduction of the compound (4), tetrahydrohinokiresinol dimethyl ether was obtained. On reduction followed by dehydration of the compounds (4) and (8), dimethyl ethers of dihydrohinokiresinol and hinokiresinol were obtained, respectively.  相似文献   

13.
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   

14.
The synthesis of (±)-licarin-B, a neolignan of Licaria aritu Ducke (Lauraceae), was achieved by pyrolysis of 3-hydroxy-3-piperonyl-1-propyl-2-methoxy-4-(E)-propenylphenyl ethers.  相似文献   

15.
The enzymatic properties of P2-2 enzyme were determined by using cells of M. radiodurans. The enzyme was: most active at 60°C incubation temperature, stable at 40°C in neutral buffer, and inactivated by heating at 80°C for 15min. Maximal lytic activity occurred at pH 8.5 in Tris-HCl buffer. The range of enzyme stability was between pH 5.5 and 8. Bivalent metal ions, p-chloromercuribenzoate and monoiodo acetate inhibited lytic activity. The molecular weight was estimated to be 16,000 daltons by gel filtration on Sephadex G-75. The enzymatic digestion of peptidoglycans from the cell walls of M. radiodurans and M. lysodeikticus liberated free amino groups, but neither reducing groups nor N-acetylhexosamine, indicating that the enzyme was an endopeptidase. From analysis of the N-terminal amino acids of the digests, it is suggested that the P2-2 enzyme cleaves the peptide bond at the carboxyl group of D-alanine in peptidoglycan.  相似文献   

16.
(±)Hydroxytremetone (III) has been synthesized from 2-(α-hydoxyisopropyl)-6-hydroxycoumaran (V b) via its O-acetate V c by dehydration with phosphorus tribromide in pyridine solution, followed by acylation with a mixture of trifluoroacetic anhydride and acetic acid. Isohydroxytremetone (IX b) was also synthesized.  相似文献   

17.

Introduction

Multiple studies have shown that glial cells of the spinal cord, such as astrocytes and microglia, have close contact with neurons, suggesting the term tripartite synapse. In these synapses, astrocytes surrounding neurons contribute to neuronal excitability and synaptic transmission, thereby increasing nociception and thus the persistence of chronic pain. Conversely, the N-methyl-D-aspartate (NMDA) receptor is crucial in the generation and maintenance of chronic pain. It has multiple sites of modulation. One is the site of recognition of extracellular neurotransmitter (glutamate), which can be blocked by competitive antagonists such as (3-(2-carboxipiperazin-4)1-propyl phosphonic acid), (±)-CPP, resulting in a blockade of the calcium current and thus the intracellular transduction process. In the present study, we investigated whether the potential antinociceptive effect of glial inhibition produced by propentofylline (PPF) can be enhanced when combined with an NMDA-receptor inhibitor such as (±)-CPP.

Methods

We used Sprague-Dawley monoarthritic rats. The monoarthritis was induced by injection of complete Freund adjuvant in the right tibiotarsal joint. Four weeks later, rats were treated with PPF (1, 10, 30, and 100 μg/10 μl) intrathecally (i.t.) for 10 days, injected once with (±)-CPP (2.5, 5, 12.5, 25, 50, and 100 μg/10 μl, i.t.), or both treatments combined. The antinociceptive effect was evaluated on day 11 for PPF and immediately to (±)-CPP, by assessing the vocalization threshold to mechanical stimulation of the arthritic paw.

Results

The data indicate that intrathecal administration of increasing concentrations of (±)-CPP or PPF produced a significant dose-dependent antinociceptive effect with respect to monoarthritic rats receiving saline. The linear regression analysis showed that the dose that produces 30% of maximal effect (ED30) for i.t. (±)-CPP was 3.97 μg, and 1.42 μg for i.t. PPF. The administration of the PPF and (±)-CPP combination in fixed proportions of ED30 produced a dose-dependent antinociceptive effect, showing an interaction of the supraadditive type.

Conclusions

The results suggest that glia inhibitors can synergically potentiate the effect of glutamate blockers for the treatment of chronic inflammatory pain.  相似文献   

18.
Resolution of (±)3-quinuclidinol into its enantiomers was obtained, at relatively high yield, based on the stereoselective enzymatic hydrolysis of R-(?)-3-quinuclidinyl butyrate by horse serum butyrylcholinesterase. The S-(+) isomer of 3-quinuclidinol was obtained from the racemate of 3-quinuclidinyl butyrate by a complete digestion of the (?) ester; the R-(?) isomer of 3-quinuclidinol was prepared by a partial hydrolysis of the racemate. The enantiomers obtained by this method were of high optical purity ([α]D25 = (+)46°). The cholinergic interactions of the benzilate esters of the 3-quinuclidinol enantiomers were characterized in mice in vivo and in isolated guinea pig ileum. The R to S potency ratio is around 10–15 for the muscarinic antagonist 3-quinuclidinyl benzilate (QNB) in the in vivo experiments compared to the reported ratio of 100 in competition experiments in vitro.  相似文献   

19.
An alternative synthesis of (±)-tubaic acid (I), a key intermediate compound of rotenone synthesis, has been accomplished by the Wittig reaction.  相似文献   

20.
A lipase gene (lip) and its activator gene (act) on a 2.9 kb BglII-EcoRI fragment from Pseudomonas sp. KWI-56 were cloned in Escherichia coli using pUC19 as a vector plasmid. From the sequencing results, the open reading frames of the lip and the act were found to contain 1092 and 1032 nucleotides, respectively. The act existed downstream of the lip with the same orientation. When the lip was expressed in E. coli using the lac promoter on the pUC plasmid vector, the lipase activity of E. coli carrying both the lip and the act was 200-fold greater than that carrying only the lip. This result suggested the act was important in the expression of the lip in E. coli.  相似文献   

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