Sartorymensin,a new indole alkaloid,and new analogues of tryptoquivaline and fiscalins produced by Neosartorya siamensis (KUFC 6349)

Seven new indole alkaloids including a new indoloazepinone derivative (2), two new quinazolinone derivatives (7, 8) and four new pyrazinoquinazolinone derivatives: epi-fiscalin C (10), epi-fiscalin A (12), neofiscalin A (13), epi-neofiscalin A (14) were isolated, together with 4-dihydroxy-3-methylacetophenone (1), tryptoquivaline (3), tryptoquivalines L (4), H (5), F (6) as well as fiscalins A (11) and C (9), from the culture of the fungus Neosartorya siamensis (KUFC 6349). The absolute configuration of the stereogenic carbons of the previously reported tryptoquivalines F, H, L was revised using the data obtained from an X-ray analysis of tryptoquivaline l and the NOESY correlations. The structures of the new pyrazinoquinazolinone derivatives (10, 12, 13, 14) were established based on 1D and 2D NMR spectral analysis, and the absolute configuration of their stereogenic carbons was determined by an X-ray crystallographic analysis of fiscalin C (9) and a new compound epi-fiscalin C (10), in conjunction with the correlations observed in their NOESY and long range COSY spectra. Compounds 2–8 and 12 were evaluated for their in vitro growth inhibitory activity on the human U373 and Hs683 glioblastoma, the A549 non-small cell lung cancer, the MCF-7 breast cancer and the SKMEL-28 melanoma cell lines by MTT colorimetric assay.     

An ESR study of various anthrasemiquinone radical anions obtained by in situ electrochemical method

Electron spin resonance spectra of seven derivatives of 9,10-anthrasemiquinone and 1,4-anthrasemiquinone are studied. These radicals have been obtained by in situ electrochemical reduction of the parent molecules.The compounds studied are: 9,10- (1), 2-chloro-1,4-dihydroxy-9,10- (2), 2,3-dichloro-1,4-dihydroxy-9,10-(3), 1,4-diacethoxy-6,7-dimethyl-9,10- (4), 1,4-dichloro- (5), 1,4-dihydroxy-9,10-anthrasemiquinone (6) and 9-chloro-10-methoxy-1,4-anthrasemiquinone (7).The hyperfine coupling constants (hfs) and the corresponding g factor are given. The assignment of these hfs is justified.     

Phloroglucinol derivatives and a chromone glucoside from the leaves of Myrtus communis

Seven new phloroglucinol derivatives, myrtucommunins A–D (1–4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-β-d-glucopyranoside (7), and one new chromone derivative, undulatoside A 6′-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A–D (1–4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1–4 were confirmed to be l in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFT calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 6/6/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1–8 and related known compounds were evaluated.     

Force field-SCF calculations on cyclopropene intermediates in carbene rearrangements. Comparison with experiment

Heats of formation and geometries of benzocyclopropene, cyclopropa[b]naphthalene, bicyclo[4.1.0]hepta-2,4,7-triene, and benzannelated derivatives have been calculated with a combined force field-SCF program. The bicycloheptatrienes are stabilized relative to the isomeric arylcarbenes by benzannelation, and destabilized by loss of aromaticity and/or increased strain. 1-Naphthylcarbene, 2-naphthylcarbene, 9-phenanthrylcarbene and 9-anthrylcarbene were generated by gas-phase pyrolysis of the corresponding arene aldehyde tosylhydrazone sodium salts, diazomethanes, or 5-aryltetrazoles, and rearranged to cyclobuta[de]naphthalene (21), cyclobuta[jk]phenanthrene (33), and cyclobuta[de] anthracene (38), respectively. 10,11-Dihydrodibenzo[ad]cyclohepten-5-ylidene (15), similarly generated from 5-diazo-10,11-dihydro-5H-dibenzo [ad]cycloheptene(39), rearranged to 5a,9b-dihydro-5H-benzo[3,4]cyclobut[1,2-a] indene(40), 5H-dibenzo[ad]cycloheptene(41), and 8,9-dihydro-4H-cyclopenta[def]phenanthrene(44).40 rearranged thermally to 41. The mechanisms of the rearrangements are discussed.     

Prenylated indole alkaloids and chromone derivatives from the fungus Penicillium sp. SCSIO041218

Four new prenylated indole alkaloids (1–4), and four new chromone derivatives (7–10), together with six known compounds (5, 6, and 11–14), have been isolated from the mangrove sediment derived fungus Penicillium sp. SCSIO041218, cultured in the 1% NaCl PDB substrate. The structures of new compounds were determined by analysis of the NMR and MS spectroscopic data. The absolute configuration of the prenylated indole alkaloids were elucidated based on the comparison of ECDs with known analogues. The absolute configurations of the chromone derivatives were determined by time-dependent density functional theory calculations of the ECD spectra. In all of these isolated compounds, penixanthones A and B (12 and 13) exhibited antiallergic activities in vitro.     

New aplysiatoxin derivatives from the Okinawan cyanobacterium Moorea producens

The marine cyanobacterium Moorea producens is a rich source of diverse compounds that possess a variety of biological activities. In the present study, eight new aplysiatoxin derivatives, namely 6, 8–13, and 15, along with aplysiatoxin (1), debromoaplysiatoxin (2), 3-methoxyaplysiatoxin (3), anhydroaplysiatoxin (4), anhydrodebromoaplysiatoxin (5), oscillatoxin B2 (7), and 30-methyloscillatoxin D (14) were isolated and identified from the Okinawan M. producens. In cytotoxicity and diatom growth inhibition tests, the fifteen compounds tested (1–15) showed moderate or no activity at a concentration of 10?μg/mL.     

Stereochemical studies-XXXIII. Saturated heterocycles-IX: Synthesis and conformations of stereoisomeric cis- and troans-tetramethylene- and pentamethylenedihydro-1,3-oxazines

By the reaction of cis- and trans-2-aminomethylcyclohexanol (1, 2), cis- and trans-2-hydroxymethyl-cyclohexylamine (3,4) and the homologous cycloheptane derivatives (5-8) with ethyl p-chlorobenzimidate (11), cis- and trans-5,6-tetramethylene- and pentamethylene-2,3,5,6-tetrahydro-4H-1,3-oxazines (12,13,16,17) and cis- and trans-4,5-tetramethylene- and pentaimethylene-4,5-dihydro-6H-1,3-oxazines (14, 15, 18, 19) were prepared. The amidine intermediate of the ring-closure reaction was isolated, and the mechanism of the acid-catalysed reaction is discussed. It follows from the ¹H NMR data that in the preferred conformations of the cis-tetramethylene-tetrahydrooxazines the methylene group of the hetero ring is equatorial and the hetero atom (O or N) axial. In contrast, the conformation equilibria of the cis pentamethylene derivatives, in accordance with earlier X-ray analysis, are shifted towards the conformer containing the methylene group in isoclinal and the hetero atom in equatorial position. The preferred conformations 12a and 14a of the tetramethylene derivatives 12 and 14 were also determined by X-ray crystal analysis.     

Chemistry of renieramycins. Part 13: Isolation and structure of stabilized renieramycin type derivatives,renieramycins W–Y,from Philippine blue sponge Xestospongia sp., pretreated with potassium cyanide

Three new bistetrahydroisoquinoline marine natural products, renieramycins W (1w), X (1x), and Y (1y), along with two known renieramycins M (1m) and T (1t), were isolated from the pretreated Philippine blue sponge Xestospongia sp. with KCN and their structures were elucidated by comparing their spectral data with those of 1m, 1t, and N-acetylsafracin B (11). Renieramycins W (1w) and X (1x) are the first examples of tiglic acid ester derivatives at the C-1 side chain. Renieramycin Y (1y) possesses a characteristic substitution pattern in A-ring and isolation of it from marine organism strongly evidences to link the possible precursor 3-hydroxy-5-methyl-O-methyltyrosine with both renieramycin and ecteinascidin marine natural products.     

Bioactive polyketides from the sea fan-derived fungus Penicillium citrinum PSU-F51

Five new polyketides including two benzopyranones (1 and 2), one isochroman (3) and two anthraquinone-citrinin derivatives (4 and 5) were isolated from the sea fan-derived fungus Penicillium citrinum PSU-F51 together with thirteen known compounds. The structures were determined by spectroscopic methods. The anthraquinone-citrinin derivatives are rare natural products. Compound 4 displayed moderate antibacterial activity against both Staphylococcus aureus and methicillin-resistant S. aureus with equal MIC values of 16 μg/mL, while the known coniochaetone A displayed moderate antifungal activity against Candida albicans with MIC value of 16 μg/mL.     

Further studies on the sesquiterpene ketone germazone

Germazane type sesquiterpenoids germazol (2), 7(11)-dihydrogermazol (3), 7(11)-dihydrogermazone (4), germazene-7(11) (17) and germazane (18) have been prepared from germazone (1). The presence and location of the cyclobutane ring in germazone (1) was confirmed by the acid-catalyzed cleavage of 2 to the cis-eudesmane derivatives 6,7 and 8.     

Cytotoxicity evaluation of coumarin derivatives containing 4-bromophenyl or anthracene moieties

The cytotoxic properties of four synthesized coumarin derivatives containing 4-bromophenyl or anthracene moieties against the human hepatocellular carcinoma cell lines (HepG-2) were investigated in vitro by use of the sulforhodamine B (SRB) assay. The four coumarin derivatives are 3-(4-bromophenyl)-benzo[5,6]coumarin (1a), 3-(4-bromophenyl)-7-(N,N-diethylamino)coumarin (1b), 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin (2a), and 3-(4-(anthracen-10-yl)phenyl)-7-(N,N-diethylamino)coumarin (2b). The preliminary results indicate that 1a, 2a, and 2b have significant cytotoxicity against HepG-2 whereas 1b has a growth-promotion effect.     

New borrelidin derivatives from an endophytic Streptomyces sp.

Three new borrelidin-type macrolactones, designated as borrelidins J?L (4–6), together with borrelidin A (1), borrelidin E (2), and 12-desnitrile-12-carboxyl-borrelidin (3) were isolated from a plant endophytic Streptomyces sp. NA06554. Their structures were determined by extensive spectroscopic analysis including HRESIMS, 1D and 2D NMR data. The antibacterial activities for compounds 1–6 were examined. Borrelidins A (1) and L (6) showed potent and moderate antibacterial activity against Micrococcus luteus, respectively, whereas other derivatives (2–5) are almost inactive, which allows us to propose a plausible structure-activity relationship.     

Methylation of zoanthoxanthins

The methylation of parazoanthoxanthin D (1) and zoantboxanthin (2), two natural tetrazacyclopentazulene pigments from Parazoanthus axinellae, has been examined under various conditions. As a rule, methylation in neutral or acidic conditions proceeds preferentially at N-1, while in liquid ammonia zoanthoxanthins are attacked by methyl iodide exclusively at the amino group at C-2. In addition to providing information on zoanthoxanthin tautomerism, the availability of various synthetic derivatives (3–10) led to the identification of the methyl derivatives 4 and 9 in Parazoanthus axinellae, and of 5 in Epizoanthus arenaceus, another zoanthid commonly found in the Bay of Naples.     

New prostanoids from soft coral

Four new anti-tumor active prostanoids, named claviridenone-a (3), claviridenone-b (4). claviridenone-c (5), and claviridenone-d (6), as well as 20-acetoxy-claviridenone-b (7) and 20-acetoxy-claviridenone-c (8), have been isolated from the Okinawan soft coral (stolonifer) Clavularia viridis Quoy and Gaimard (Stolonifera, Clavulariidae). The absolute stereostructures of these six prostanoids have been elucidated on the basis of chemical and physicochemical evidence which includes the application of the CD exciton chirality method to their various benzoyl derivatives having benzoate and conjugated diene chromophores. Claviridenones possess a characteristic cross-conjugated dienone-enone chromophore.     

Some diterpenes from the sea pen stylatula SP.

The sea pen Stylatula sp. from the Gulf of California contained one major and several minor metabolites. The structure of stylatulide (2), the major metabolite, has been reported previously. In this paper, the structural elucidations of four minor metabolites, 17-epi-stylatulide (13), the lactone 14, the primary alcohol 15 and related methyl ester 17 are described. We have described several reactions of stylatulide (2) and its derivatives which illustrate the complexity of reactions on these compounds.     

Two novel iridoid derivatives isolated from Phlomis likiangensis

The extract of the aerial and underground parts of Phlomis likiangensis afforded two new iridoid derivatives, namely as phloloside H (1) and phloline (2), along with four known compounds (3–6), and compound 2 was a novel normonoterpene. Their structures were elucidated on the basis of spectroscopic studies and chemical methods. Six compounds were assayed for cytotoxic, antibacterial and antioxidative activities, but were either inactive or very weakly active.     

Solid-state structures of sym-dibenzo-16-crown-5 and its derivatives

Solid-state structures of sym-dibenzo-16-crown-5 (1) and five derivatives with one or two substituents on the three-carbon bridge have been determined. The derivatives with three sp³-hybridized carbons include sym-(propyl)dibenzo-16-crown-5 (4), sym-(pentafluorophenoxy)-dibenzo-16-crown-5 (5), and sym-[di(methoxymethyl)]dibenzo-16-crown-5 (6). Structures of two derivatives with sp²-hybridization of the central carbon (7 and 8) were also determined. Twisting of the three-carbon bridge causes one of the terminal methylene groups to be oriented within the polyether cavity.     

Constituents of morphologically similar sponges : Aplysina and smenospongia species

Compounds from the marine sponge Smenospongia aurea have been isolated and characterized as 5-bromo- and 5,6-dibromo-N,N-dimethyltryptamines (1 and 2), aureol (3), and two new aplysinopsin derivatives (6-bromoaplysinopsin and 6-bromo-4'-N-demethylaplysinopsin, 4 and 5, respectively). Morphologically similar species from the Caribbean have been surveyed and found to contain either mixtures of these metabolites or bromotyrosine-derived compounds. ¹H NMR spectra of bromoindole-containing metabolites are discussed.     

Synthesis of some novel sulfonyl ester derivatives derived from d-mannitol

The preparation of sulfonate-derivatives of d-mannitol i.e. 1,2:3,4-di-O-isopropylidene-3,4-di-O-p-toluenesulfonate-d-mannitol (3a), 1,2:3,4-di-O-isopropylidene-3,4-di-O-methanesulfonate-d-mannitol (3b), and 1, 2:3,4-di-O-isopropylidene-3,4-di-O-trifluoromethanesulfonate-d-mannitol (3c) is described. Full characterization and methodologies of these sulfonate-d-mannitol derivatives have been described as well.     

The constitution of vertinolide,a new derivative of tetronic acid,produced by Verticillium intertextum

From the culture of Verticillium intertextrum a new tetronic acid derivative, vertinolide, has been isolated as the main constituent of the chloroform extract. Structure 1a was established for vertinolide by X-ray diffraction analysis. Vertinolide (1a) was also transformed to an O-methyl-(1b), an O-acetyl-(1c), a tetrahydro- (1d) and a tetrahydro-O-methyl-derivative (4). The spectroscopic properties of 1a, of its derivatives 1a, 1c, 1d and 4 as well as of three model compounds are compared and discussed.