Discovery of prenylated indole alkaloid and natural xanthone from cold-seep sediment derived fungus Talaromyces funiculosus SD-523

A new prenylated indole alkaloid 11,17-epi-mangrovamide A(1),a new natural occurring product,1,7-dihydroxy-6-methyl-8-hydroxymethyl-xanthone(2),two known alkaloids,mangrovamide A(3)and mangrovamide G(4),and four known polyketide derivatives(5–8)were isolated and identified from the cold-seep sediment derived fungal strain Talaromyces funiculosus SD-523.Their structures were elucidated by combination of nuclear magnetic resonance(NMR),high resolution electrospray ionization mass spectroscopy(HRESIMS),quantum chemical electronic circular dichroism(ECD),and DP4+probability analysis as well as by comparison of the data with literature reports.All isolated compounds were tested for antibacterial activities.

A new monoterpenoid indole alkaloid from Rauvolfia yunnanensis

One new monoterpenoid indole alkaloid, l l-methoxyburnamine-17-O-3′,4′,5′-trimethoxybenzoate （1）, was isolated from Rauvolfia yunnanensis Tsiang. Its structure was identified by speclroscopic evidences.

New Greener Alternative for Biocondensation of Aldehydes and Indoles Using Lemon Juice: Formation of Bis-, Tris-, and Tetraindoles

This work presents a new greener alternative for biocondensation of aldehydes and indoles for the synthesis of bis- and tris(indolyl)methanes catalyzed by lemon juice (Citrus limon) in good yields under ultrasound irradiation in aqueous ethanol. Various substituted aldehydes with indoles under this reaction condition are elucidated. Also, tetraindolyl compounds were prepared using terephthaldialdehyde by following the same protocol. This method is an environmentally benign, efficient reaction, which requires shorter reaction time and simple experimental and work-up procedures.

Synthesis and Crystal Structure of 3-(Trichloroacetyl) Indole

Trichloroacetyl) indole has been synthesized by the reaction of indole with trichloroacetyl chloride in 73% yield, and its crystal structure was determined by X-ray diffraction method. The crystal is of orthorhombic, space group Pnma with a = 20.781(7), b = 6.857(2), c = 7.431(3) ?, V = 1058.8(6) ?3, Z = 4, Mr = 262.51, Dc = 1.647 g/cm3, λ = 0.71073 ?, μ(MoKα) = 0.833 mm? and F(000) = 528. The structure was refined to R = 0.0286 and wR = 0.0749 for 1073 1 observed reflections with I > 2σ(I). It exhibits a characteristic plane structure consisting of all atoms except Cl(2) and Cl(2)A. Two kinds of intermolecular hydrogen bonds are formed: N(1)– H(8A)…O(1) and N(1)–H(8A)…Cl(1). There also exist three kinds of π-π stacking in the crystal.

Construction of Spirooxindole Skeleton Through Intramolecular Dieckmann Cyclization

A highly efficient and direct approach was developed to construct the structurally diverse spirooxindole skeleton,which is an important basic motif in natural products.Both the 3,30-pyrrolidonyl spirooxindoles and spiroindolin-2-one dlactones were 2smoothly obtained by the intramolecular Dieckmann cyclization of oxindoles in excellent yield under mild conditions.

Synthesis and Crystal Structure of 3-(1-Ethyl-1H-indole-3-carbonyl)aminopropionic Acid

3-（1-Ethyl-1H-indole-3-carbonyl）aminopropionic acid has been synthesized by alkylation of 3-（1H-indole-3-carbonyl）aminopropionic acid methyl ester with bromoethane,follo-wed by saponifying and acidating,in 89.0% yield.Its crystal structure was gotten and determined by X-ray diffraction method.The crystal is of orthorhombic,space group P212121 with a = 8.9490（12）,b = 11.1010（15）,c = 13.0475（18） ,V = 1296.2（3） 3,Z = 4,Dc = 1.334 g/cm3,λ = 0.71073 ,μ（MoKα） = 0.095 mm-1,Mr = 260.29 and F（000） = 552.The structure was refined to R = 0.0306 and wR = 0.1445 for 2612 observed reflections with I 2σ（I）.In the crystal structure,molecules are linked to each other through hydrogen bonds of N（2）-H（2）···O（1） and O（3）-H（3）···O（1）,generating a three-dimensional network.

Synthesis and Crystal Structure of Methyl 3-(5-Bromo-1-ethyl-1H-indole-3-carbonyl)aminopropionate

Methyl 3-（5-bromo-l-ethyl-lH-indole-3-carbonyl）aminopropionate has been synthesized by the acylation of 5-bromo-3-trichloroacetylindole with β-alanine methyl ester, followed by alkylation with ethyl iodide, in 82.6% yield. Its crystal structure was gotten and determined by X-ray diffraction method. The crystal is of monoclinic, space group P2/c with a = 11.7927（8）, b = 14.9342（8）, c = 9.0060（5） A, β = 101.558（6）°, V = 1553.93（16） A3, Z = 4, Dc= 1.510 g/cm3, 2 = 0.71073 A,μ（MoKa） = 2.656 mm-1, Mr = 353.22 and F（000） = 720. The structure was refined to R = 0.0401 and wR = 0.0825 for 1704 observed reflections with I 〉 2σ（I）. In the crystal structure, intermolecular N（2）-H（2）...O（1） hydrogen bond and weak intermolecular bonds （C（1）-H（1）...O（1） and C（10）-H（10B）-O（2）） are formed, and π-π stacking also exists.

Structural characterization of monoterpene indole alkaloids in ethanolic extracts of Rauwolfia species by liquid chromatography with quadrupole time-of-flight mass spectrometry

Rauwolfia species(Apocynaceae) are medicinal plants well known worldwide due to its potent bioactive monoterpene indole alkaloids(MIAs) such as reserpine,ajmalicine,ajmaline,serpentine and yohimbine.Reserpine,ajmalicine and ajmaline are powerful antihypertensive,tranquilizing agents used in hypertension.Yohimbine is an aphrodisiac used in dietary supplements.As there is no report on the comparative and comprehensive phytochemical investigation of the roots of Rauwolfia species,we have developed an efficient and reliable liquid chromatography-tandem mass spectrometry(LC–MS/MS) method for ethanolic root extract of Rauwolfia species to elucidate the fragmentation pathways for dereplication of bioactive MIAs using highperformance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry(HPLC–ESI–QTOF–MS/MS) in positive ion mode.We identified and established diagnostic fragment ions and fragmentation pathways using reserpine,ajmalicine,ajmaline,serpentine and yohimbine.The MS/MS spectra of reserpine,ajmalicine,and ajmaline showed C-ring-cleavage whereas E-ring cleavage was observed in serpentine via Retro Diels Alder(RDA).A total of 47 bioactive MIAs were identified and characterized on the basis of their molecular formula,exact mass measurements and MS/MS analysis.Reserpine,ajmalicine,ajmaline,serpentine and yohimbine were unambiguously identified by comparison with their authentic standards and other 42 MIAs were tentatively identified and characterized from the roots of Rauwolfia hookeri,Rauwolfia micrantha,Rauwolfia serpentina,Rauwolfia verticillata,Rauwolfia tetraphylla and Rauwolfia vomitoria.Application of LC–MS followed by principal component analysis(PCA) has been successfully used to discriminate among six Rauwolfia species.

Engineering Terpenoid Indole Alkaloids Biosynthetic Pathway in Catharanthus roseus Hairy Root Cultures by Overexpressing the Geraniol 10-hydroxylase Gene

Catharanthus roseus contains important anti-tumor terpenoid indole alkaloids (TIAs) such as vinblastine and vincristine. Cytochrome P450 enzyme geraniol 10-hydroxylase (G10H) is a putative rate-limiting enzyme involved in the TIAs biosynthetic pathway in C. roseus. In this study the g10h gene driven by the cauliflower mosaic virus 35S (CaMV 35S) promoter was introduced into C. roseus through Agrobacterium-mediated transformation. The integration and overexpression of the target gene (g10h) in hairy root lines were confirmed by polymerase chain reaction and RT-QPCR analysis respectively. Overexpression of g10h in transgenic hairy root lines significantly enhanced the accumulations of monomeric alkaloid ajmalicine and dimeric alkaloids, vincristine and vinblastine. Total TIAs production in hairy roots reached (9.51) mg/g DW, over 3-fold higher than that in the untransformed root lines. This is the first report that engineering of g10h into TIAs-producing plant species results in significant enhancement of TIAs accumulation in cultured hairy roots. This study demonstrates that the putative rate-limiting step catalyzed by G10H is indeed the real rate-limiting step involved in the TIAs biosynthetic pathway in C. roseus, which is one of the key targets for promoting TIAs production by genetic engineering.

Gallium trichloride-catalyzed conjugate addition of indole and pyrrole to α,β-unsaturated ketones in aqueous media

Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.

Indole Alkaloids from the Roots of Ervatamia hainanensis

Two new indole alkaloids, named ibogamine-18-carboxylic acid, 3, 4-didehydro-7, 8-dioxo-methyl ester 1, ibogamine-18-carboxylic acid, 16, 17-didehydro-9, 17-dihydro-9-hydroxy （2-oxopropyl）-methyl ester 2, were isolated from Ervatamia hainanensis. Their structures were elucidated on the basis of spectroscopic methods.

Four new indole alkaloids from Plantago asiatica

Four new indole alkaloids,plasiaticines A-D(1-4),together with two known ones,were isolated from the seeds of Plantago asiatica.The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data.All compounds were tested for their cytotoxic activity,and all compounds except 4 were tested for their acetylcholinesterase(AChE)inhibitory activities.

Indole Alkaloids Inhibiting Neural Stem Cell from Uncaria rhynchophylla

Uncaria rhynchophylla is commonly recognized as a traditional treatment for dizziness,cerebrovascular diseases,and nervous disorders in China.Previously,the neuro-protective activities of the alkaloids from U.rhynchophylla were intensively reported.In current work,three new indole alkaloids(1–3),identified as geissoschizic acid(1),geissoschizic acid N4-oxide(2),and 3b-sitsirikine N4-oxide(3),as well as 26 known analogues were isolated from U.rhynchophylla.However,in the neural stem cells(NSCs)proliferation assay for all isolated compounds,geissoschizic acid(1),geissoschizic acid N4-oxide(2),isocorynoxeine(6),isorhynchophylline(7),(4S)-akuammigine N-oxide(8),and(4S)-rhynchophylline N-oxide(10)showed unexpected inhibitory activities at 10 μM.Unlike previous neuro-protective reports,as a warning or caution,our finding showcased a clue for possible NSCs toxicity and the neural lesions risk of U.rhynchophylla,while the structure–activity relationships of the isolated compounds were discussed also.

Monoterpenoid Indole Alkaloids from Inadequately Dried Leaves of Alstonia scholaris

Six new indole alkaloids,named alstoniascholarines L–Q(1–6),together with nineteen known analogues were isolated from the inadequately dried leaves of Alstonia scholaris.Their structures were elucidated on the basis of extensive analysis of spectroscopic data and by comparison of their physical and spectroscopic data with the literature values.In addition,the new alkaloids were tested for their cytotoxic and neurite outgrowth-promoting activities.

Effect of Indole 3-Butyric Acid and Media Type on Adventitious Root Formation in Sheanut Tree (<i>Vitellaria paradoxa</i>C. F. Gaertn.) Stem Cuttings

Shea nuts play an important role in food security for rural folks within sub-Sahara Africa, serving as the main source of income for many people living in Northern Ghana. Unfortunately, the full economic potential of the Sheanut tree has not been fully realized due to the difficulty involved in its domestication. This difficulty in vegetatively propagating sheanut trees has greatly hindered its cultivation and the realization of its true economic potential. Two experiments were conducted to investigate the effects of rooting media and varying indole 3-butyric acid (IBA) concentrations on adventitious root formation in cuttings taken from coppiced sheanut trees. Results indicated that 3000 ppm produced significantly (p 0.05) better rooting (57.5%) than 5000 ppm (30%), 7000 ppm (45.0%) and the control (7.5%). Although the levels of soluble sugars (SS) and total free phenols (TFP) in the cutting were significantly (p 0.05) higher at the end of the experiment (after IBA treatment) compared to the start (prior to IBA treatment), the SS and TFP trends observed did not clearly explain the rooting differences found between the IBA levels investigated. Callus formation was significantly (p 0.05) higher (35.0%) in the control (no IBA). Generally, callus formation decreased with increasing IBA concentration. In the rooting media experiment, rooting was significantly (p 0.05) higher in the rice husk medium (35.0%) compared to that in the palm fiber (18.3%), saw dust (14.1%) and top soil (16.7%) media.

Monoterpenoid indole alkaloids from Alstonia rostrata

Four new monoterpenoid indole alkaloids,alstrostines C-F together with thirteen known alkaloids were isolated from the leaves and twigs of Alstonia rostrata.All structures of new compounds were elucidated based on NMR,FTIR,UV,and MS spectroscopic data.Alstrostines C-E might originate from keto-enol tautomerism of preakummicine during biogenetic pathway of akummicine.

Reactivity of Indoles through the Eyes of a Charge-Transfer Partitioning Analysis

A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the most reactive atoms on each reactant,combined with the spatial distribution of the nucleophilic and electrophilic Fukui functions of both reactants,allows one to propose non-trivial candidates of starting geometries for the search of the transition state structures present in these reactions.

Synthesis of Novel 1-Alkyl-2-chloro(alkoxy)-1H-indole 3-Carbaldehyde Oximes and Oxime-ethers(esters) Derivatives

A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes（5a―5d） and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes（6a―6d） from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes（7a―7h） from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes（3a―3d） was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds（3a―11d） were characterized by 1H NMR,IR,MS,and elemental analysis.