共查询到20条相似文献,搜索用时 31 毫秒
1.
Jayanta Das Arunoday Bhan Subhrangsu S. Mandal Carl J. Lovely 《Bioorganic & medicinal chemistry letters》2013,23(22):6183-6187
Concise syntheses of two Leucetta-derived naphthimidazole alkaloids, kealiiquinone and 2-deoxy-2-aminokealiiquinone, are described based on a biosynthetic-guided hypothesis. Advanced intermediates containing the full naphthimidazole framework are constructed through Friedel–Crafts chemistry followed by oxidation of the electron rich C-ring with hydrogen peroxide. The cytotoxicity of these alkaloids in a breast cancer cell line along with several closely related marine-derived natural products kealiinines A–C and analogs are reported. 相似文献
2.
The alternate and optimized syntheses of the parent opioid fentanyl and its analogs are described. The routes presented exhibit high-yielding transformations leading to these powerful analgesics after optimization studies were carried out for each synthetic step. The general three-step strategy produced a panel of four fentanyls in excellent yields (73–78%) along with their more commonly encountered hydrochloride and citric acid salts. The following strategy offers the opportunity for the gram-scale, efficient production of this interesting class of opioid alkaloids. 相似文献
3.
Two new ester alkaloids, desmethoxyabresoline and 10-epi-desmethoxyabresoline, have been isolated from young seedlings of Heimia salicifolia and have been synthesized. Chemical and physical properties of the natural and synthetic isomers are in agreement. The presence of these alkaloids adds support to the postulate that the biphenyl system of the lythraceous alkaloids is derived from trans-cinnamate esters of phenylquinolizidinols. 相似文献
4.
《Phytochemistry》1986,25(10):2399-2401
From bulbs of Crinum americanum oxocrinine, an intermediate in the biosynthesis of Amaryllidaceae alkaloids, was isolated for the first time. In addition, the plant contains crinine, flexinine, O-acetylcrinine, lycorine, hippadine, pratorinine, pratorimine, pratosine, ungeremine and trisphaeridine. The alkaloids were identified by spectroscopic evidence, chemical transformations and partial syntheses. 相似文献
5.
The first total synthesis of 7-O-β-d-glucopyranosyl-4′-O-α-l-rhamnopyranosyl apigenin 1, which exhibits good anti-hepatitis B virus and anti-stroke activities, was accomplished in six steps and 20% overall yield from apigenin. Another synthetic route, in which the target was obtained in seven steps, was also developed to prove the utility of a hexanoyl ester-based orthogonal protection strategy. The hexanoyl protection strategy provided all the flavonoid intermediates with good solubility and reactivity, enabled efficient selective protection and glycosylation, and provided a practical and effective synthetic strategy for flavonoids, starting from commercially available flavone. 相似文献
6.
R C Audette J L Purvis L R Worthen H W Youngken 《Archives of biochemistry and biophysics》1973,154(1):173-184
Claviceps purpurea grown on synthetic medium incorporated labeled [7-14]nicotinic acid and [7-14C]nicotinamide into NaMN, des-NAD, NAD, and NADP. Label also appeared in NMN and N-methyl nicotinamide. The specific activities of NAD, NADP, and NMN are compatible with the operation of the Preiss-Handler pathway of NAD biosynthesis (nicotinic acid → NaMN → des-NAD → NAD → NADP). The relative amounts of NaMN:des-NAD:NAD and NADP were about 8:1:36:10 on incubation of Claviceps with nicotinic acid for 6 hr. The incorporation of nicotinamide into NAD proceeds mainly by conversion to nicotinic acid catalyzed by nicotinamide deamidase.Tryptophan ([U-14C]benzene ring) was incorporated into NAD demonstrating the presence of the tryptophan-nicotinic acid pathway. No qualitative difference in pyridine nucleotide intermediates was noted in C. purpurea CPM, which does not produce clavine alkaloids, and Claviceps 47A which does produce clavine alkaloids. 相似文献
7.
Shunya Takahashi Takahiro Kawano Natsumi Nakajima Yasuaki Suda Narandulam Usukhbayar Ken-ichi Kimura Hiroyuki Koshino 《Bioorganic & medicinal chemistry letters》2018,28(5):930-933
Polyozellin is a p-terphenyl compound which was isolated from Polyozellus multiplex, and exhibits an inhibitory activity against prolyl oligopeptidase (POP). Its structure was assigned as 1 having a p-terphenyl skeleton including a p-substituted dibenzofuran moiety by spectroscopic analyses and chemical means. This paper describes the total syntheses of the proposed structure 1 for polyozellin and its o-isomer 2, revising the structure of polyozellin to the latter. These syntheses involved a double Suzuki-Miyaura coupling using chlorophenylboronic acid as a common key building block, and Cu mediated Ullmann cyclization as key steps. The inhibitory activities of synthetic compounds against POP and cancer cells were also evaluated. 相似文献
8.
4-Hydroxycinnamaldehydes are key intermediates in the biosynthesis and degradation of lignins, the class of aromatic polymers that are responsible for much of the recalcitrance in converting lignocellulosic biomass to liquid fuels. Access to these aldehydes is needed for investigation of biochemical pathways, a crucial step in manipulating lignin biosynthesis for cost-effective biofuels production. Here, p-coumaraldehyde, caffealdehyde, coniferaldehyde, and sinapaldehyde were efficiently prepared by coupling the corresponding 4-hydroxycinnamic acids with N,O-dimethylhydroxylamine, followed by selective reduction with diisobutylaluminum hydride. The protecting-group-free total synthesis of these aldehydes does not require the use of a controlled atmosphere, nor chromatographic purification; thus, although it remains in the realm of moderately well-trained synthetic chemists, the syntheses are particularly convenient. 相似文献
9.
Shinya Shiomi Kohei Wada Yuhei Umeda Hikaru Kato Sachiko Tsukamoto Hayato Ishikawa 《Bioorganic & medicinal chemistry letters》2018,28(16):2766-2769
Total syntheses of prenylated pyrrolidinoindoline alkaloids, (?)-mollenines A [(?)-1′] and B (2′), were accomplished via three- and four-step sequences including a bioinspired indole prenylation reaction followed by dioxomorpholine ring formation. Then, the stereochemistry of mollenines A and B was reassigned to 3S,6S,14S,16S by analysis of spectroscopic data and chemical syntheses with different approaches along with the comparison of calculated and experimental ECD spectra. In addition, a thermodynamically controlled epimerization reaction on the dioxomorpholine ring was observed in our synthesis. 相似文献
10.
《Bioorganic & medicinal chemistry letters》2014,24(15):3373-3376
Kynapcin-12 is a prolyl oligopeptidase (POP) inhibitor isolated from Polyozellus multiplex, and its structure was assigned as 1 having a p-hydroquinone moiety by spectroscopic analyses and chemical means. This Letter describes the total syntheses of the proposed structure 1 for kynapcin-12 and 2′,3′-diacetoxy-1,5′,6′,4″-tetrahydroxy-p-terphenyl 2 isolated from Boletopsis grisea, revising the structure of kynapcin-12 to the latter. These syntheses involved double Suzuki–Miyaura coupling, CAN oxidation, and LTA oxidation as key steps. The inhibitory activities of synthetic compounds against POP and cancer cells were also evaluated. 相似文献
11.
12.
A facile and effective method was developed for large-scale syntheses of myo-inositol derivatives with the 1,2,6-O-positions differentiated from each other and from other positions as well. The syntheses started from methyl α-d-glucopyranoside, and the key steps are Ferrier rearrangement and a series of other regioselective and stereoselective reactions. The target compounds are key intermediates in the synthesis of GPIs. 相似文献
13.
Under Polonovski-type conditions, ferrocene has been found to be a convenient and efficient catalyst for the N-demethylation of a number of N-methyl alkaloids such as opiates and tropanes. By judicious choice of solvent, good yields have been obtained for dextromethorphan, codeine methyl ether, and thebaine. The current methodology is also successful for the N-demethylation of morphine, oripavine, and tropane alkaloids, producing the corresponding N-nor compounds in reasonable yields. Key pharmaceutical intermediates such oxycodone and oxymorphone are also readily N-demethylated using this approach. 相似文献
14.
Hasso Rönsch 《Phytochemistry》1977,16(6):691-698
In the biosynthesis of the benzazepine alkaloid alpinigenine a N-methylation step followed by hydroxylation α to nitrogen has now been shown more conclusively to be involved in the transformation of a N-heterocyclic ring system. After feeding Papaver bracteatum plants both the precursors (±)-tetrahydropalmatine-[8,13,14-3H] and (±)-tetrahydropalmatine methiodide-[8,13,14-3H;8-4C] an identical mode of abstraction of tritium was observed including a complete loss of the isotope from C-14. The next member in the biogenetic chain, muramine-[8-14C], was incorporated into alpinigenine very efficiently. Furthermore, using structurally different precursors not utilized for normal alkaloid formation, e.g. 2′-hydroxymethyl-laudanosine-[14CH2OH], 13-hydroxymuramine-[8-14C], the specificity of alkaloid metabolism was examined in the whole plant. Tracer dilution technique was applied to confirm the occurrence in the plant of three established intermediates. Chemical syntheses of four of the alkaloids used during these investigations were developed. 相似文献
15.
Tamara Costas Pedro Besada Alessandro Piras Laura Acevedo Matilde Yañez Francisco Orallo Reyes Laguna Carmen Terán 《Bioorganic & medicinal chemistry letters》2010,20(22):6624-6627
New 6-substituted and 2,6-disubstituted pyridazinone derivatives were obtained starting from easily accessible alkyl furans by using oxidation with singlet oxygen to give 4-methoxy or 4-hydroxybutenolides, key intermediates of this synthetic strategy. The new pyridazinone derivatives have been studied as vasorelaxant and antiplatelet agents. Analysis of biological data revealed the silyl ethers (4a–i) and N,O-dibenzyl derivatives (6g–i) as the most active compounds. 相似文献
16.
Prashanthi Mulinti Natalie A. Allen Christine M. Coyle Fabrice N. Gravelat Donald C. Sheppard Daniel G. Panaccione 《Current microbiology》2014,68(1):1-5
Production of ergot alkaloids in the opportunistic fungal pathogen Aspergillus fumigatus is restricted to conidiating cultures. These cultures typically accumulate several pathway intermediates at concentrations comparable to that of the pathway end product. We investigated the contribution of different cell types that constitute the multicellular conidiophore of A. fumigatus to the production of ergot alkaloid pathway intermediates versus the pathway end product, fumigaclavine C. A relatively minor share (11 %) of the ergot alkaloid yield on a molar basis was secreted into the medium, whereas the remainder was associated with the conidiating colonies. Entire conidiating cultures (containing hyphae, vesicle of conidiophore, phialides of conidiophore, and conidia) accumulated higher levels of the pathway intermediate festuclavine and lower levels of the pathway end product fumigaclavine C than did isolated, abscised conidia, indicating that conidiophores and/or hyphae have a quantitatively different ergot alkaloid profile compared to that of conidia. Differences in alkaloid accumulation among cell types also were indicated by studies with conidiophore development mutants. A ?medA mutant, in which conidiophores are numerous but develop poorly, accumulated higher levels of pathway intermediates than did the wildtype or a complemented ?medA mutant. A ?stuA mutant, which grows mainly as hyphae and produces very few, abnormal conidiophores, produced no detectable ergot alkaloids. The data indicated heterogeneous spatial distribution of ergot alkaloid pathway intermediates versus pathway end product in conidiating cultures of A. fumigatus. This skewed distribution may reflect differences in abundance or activity of pathway enzymes among cell types of those conidiating cultures. 相似文献
17.
Convolvulaceous species have been reported to contain several bioactive principles thought to be toxic to livestock including the calystegines, swainsonine, ergot alkaloids, and indole diterpene alkaloids. Swainsonine, ergot alkaloids, and indole diterpene alkaloids are produced by seed transmitted fungal symbionts associated with their respective plant host, while the calystegines are produced by the plant. To date, Ipomoea asarifolia and Ipomoea muelleri represent the only Ipomoea species and members of the Convolvulaceae known to contain indole diterpene alkaloids, however several other Convolvulaceous species are reported to contain ergot alkaloids. To further explore the biodiversity of species that may contain indole diterpenes, we analyzed several Convolvulaceous species (n = 30) for indole diterpene alkaloids, representing four genera, Argyreia, Ipomoea, Stictocardia, and Turbina, that had been previously reported to contain ergot alkaloids. These species were also verified to contain ergot alkaloids and subsequently analyzed for swainsonine. Ergot alkaloids were detected in 18 species representing all four genera screened, indole diterpenes were detected in two Argyreia species and eight Ipomoea species of the 18 that contained ergot alkaloids, and swainsonine was detected in two Ipomoea species. The data suggest a strong association exists between the relationship of the Periglandula species associated with each host and the occurrence of the ergot alkaloids and/or the indole diterpenes reported here. Likewise there appears to be an association between the occurrence of the respective bioactive principle and the genetic relatedness of the respective host plant species. 相似文献
18.
《Process Biochemistry》2010,45(9):1577-1581
Hyoscyamine, anisodamine (6β-hydroxyhyoscyamine) and scopolamine are tropane alkaloids produced by plants belonging to the Solanaceae family such as Brugmansia candida. These alkaloids were traditionally used in medicine because of their anticholinergic activity. Further therapeutical properties for anisodamine were recently described renewing the interest in these alkaloids. The scaling-up of hairy root cultures is an interesting strategy for the pharmaceutical production of these compounds instead of the isolation from plants. In this work, B. candida hairy roots were cultured in a modified 1.5 L stirred tank in order to analyze an alternative production system of scopolamine and anisodamine. It was found that these cultures produced an increased biomass and alkaloids concentration compared to the processes carried out in Erlenmeyer flasks. Anisodamine was the predominant alkaloid reaching a maximum concentration of 10.05 ± 0.76 mg/g DW in modified bioreactor culture system. The results obtained in this work are potentially applicable for the rational scale-up of the process. 相似文献
19.
The leaves and the trunk barks of Magnolia watsonii afforded two biosynthetic intermediates of dehydrocostuslactone (watsonol A and watsonol B) along with the neolignans, magnolol, hōnokiol and obovatol, and the aporphine alkaloids, liriodenine and asimilobine. 相似文献
20.
Seikou Nakamura Souichi Nakashima Genzo Tanabe Yoshimi Oda Nami Yokota Katsuyoshi Fujimoto Takahiro Matsumoto Rika Sakuma Tomoe Ohta Keiko Ogawa Shino Nishida Hisako Miki Hisashi Matsuda Osamu Muraoka Masayuki Yoshikawa 《Bioorganic & medicinal chemistry》2013,21(3):779-787
Methanolic extracts from the flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) were found to show inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. From the methanolic extracts, a new alkaloid, N-methylasimilobine N-oxide, was isolated together with eleven benzylisoquinoline alkaloids. The absolute stereostructure of the new alkaloid was determined from chemical and physicochemical evidence. Among the constituents isolated, nuciferine, N-methylasimilobine, (?)-lirinidine, and 2-hydroxy-1-methoxy-6a,7-dehydroaporphine showed potent inhibition of melanogenesis. Comparison of the inhibitory activities of synthetic related alkaloids facilitated characterization of the structure-activity relationships of aporphine- and benzylisoquinoline-type alkaloids. In addition, 3–30 μM nuciferine and N-methylasimilobine inhibited the expression of tyrosinase mRNA, 3–30 μM N-methylasimilobine inhibited the expression of TRP-1 mRNA, and 10–30 μM nuciferine inhibited the expression of TRP-2 mRNA. 相似文献