New pyranosyl cembranoid diterpenes from Sarcophyton trocheliophorum

During our continual searching programme for novel bioactive metabolites from Sarcophyton trocheliophorum, collected from Red Sea, we describe herein the isolation and structural elucidation of further two new pyrane-based cembranoid diterpenes: 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and 8,9-expoy-sarcotrocheliol acetate (2), along with the well-known sarcotrocheliol acetate (3), (+)-sarcophine (4), (+)-sarcophytoxide (5) and (-)-sarcophytoxide (6). The chemical structures of compounds 1 and 2 were determined on the basis of 1D and 2D NMR (¹H, ¹³C, ¹H–¹H COSY, HMQC, HMBC and NOE), mass spectra (ESI and HR-ESIMS) and by comparison with related structures. The antimicrobial activities of the reported compounds 1–6 were investigated. According to the molecular docking study of compounds 1–6 using 3D structure of α,β tubulin in complex with taxol (PDB code 1JFF) and epothilone A (PDB code 1TVK), sarcophine (4) displayed the highest affinity towards both crystal structures, followed by 5 and 6, meanwhile pyrane-based cembranoid diterpenes (1–3) showed less affinity.     

A new benzofuran from Artemisia halodendron Turcz. ex Bess.

A new benzofuran, methyl (2S,2″S,3′E)-[2-(1″-acetoxypropan-2-yl)-2,3-dihydrobenzofuran-5-yl]acrylate (1), and 13 known compounds (2–14) were isolated from an ethanol extract of Artemisia halodendron Turcz. ex Bess. The chemical structures of these compounds were determined by 1D and 2D NMR (¹H-¹H COSY, HMBC, HMQC and NOESY) and HR-ESI-MS spectra, and results were compared with data from the literature. The effects of compounds 1–14 were measured on NF-κB activation, with compounds 2 and 3 exhibiting inhibitory activities against TNF-α-induced NF-κB reporter gene expression in HeLa cells from 10 to 100 μM.     

Two new diarylheptanoids isolated from the roots of Juglans mandshurica

Two new diarylheptanoids, ( ? )-threo-3′,4″-epoxy-1-(4-hydroxyphenyl)-7-(3-methoxyphenyl)heptan-2,3-diol (1) and (1α,3β,5α,6α)-1,5-epoxy-3,6-dihydroxy-1,7-bis(3-methoxy-4-hydroxy-phenyl)-heptane (2), along with one known diarylheptanoid, rhoiptelol B (3), were isolated from the roots of Juglans mandshurica. The structures of compounds 1 and 2 were identified based on HR-ESI-MS, 1D and 2D NMR including ¹H–¹H COSY, HMQC, HMBC and NOESY spectroscopic methods.     

Isolation and characterisation of three new anthraquinone secondary metabolites from Symplocos racemosa

Three new anthraquinone secondary metabolites were isolated from Symplocos racemosa, a small tree of family symplocaceae. The structures of compounds (1–3) were elucidated to be 1,4-dihydroxy-6-(ethoxymethyl)-8-propylanthracene-9,10-dione (1), 1,4-dihydroxy-6-(hydroxymethyl)-8-butylanthracene-9,10-dione (2) and 1,4-dihydroxy-6-(hydroxymethyl)-8-propyl anthracene-9,10-dione (3) using their spectral data, i.e. through IR, UV, ¹H NMR, ¹³C NMR and two-dimensional (2D) NMR techniques including heteronuclear multiple quantum coherence, heteronuclear multiple bond correlation and correlation spectroscopy.     

Design,synthesis, and anticancer activity evaluation of novel aziridine-1,2,3-triazole hybrid derivatives

Some new 1-aryl-4-[(aziridine-1-yl)diaryl-methyl]-5-methyl-1H-1,2,3-triazole derivatives 7j–s were synthesized by the one-pot reaction of diaryl-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)methanol compounds 6j–s formed from 1-aryl-5-methyl-1H-1,2,3-triazole-4-carboxylic acid derivatives. The new compounds 7j–s and 6j–s are investigated by ¹H and ¹³C NMR, MS, and IR. The anticancer activity of the synthesis target compounds was evaluated against human leukemia (HL-60) cells and human hepatoma G2 cells. Some of the compounds were highly efficient. The ¹H-NMR signals of the aziridine-ring cis-H/trans-H protons were found to be two group peaks at 1.800–1.884 and 1.183–1.327?ppm.     

Two new ionone glycosides from the roots of Rehmannia glutinosa Libosch.

Two new ionone glycosides, named frehmaglutoside G (1) and frehmaglutoside H (2), together with six known compounds, rehmapicroside (3), sec-hydroxyaeginetic acid (4), dihydroxy-β-ionone (5), trihydroxy-β-ionone (6), rehmaionoside A (7) and rehmaionoside C (8), were isolated from the 95% EtOH extract of the dried roots of Rehmannia glutinosa Libosch. Their structures were determined on the basis of extensive spectroscopic analyses, including HR-ESI-MS, UV, IR, 1D and 2D NMR (¹H–¹H COSY, HSQC, HMBC and NOESY) methods. The absolute configurations were confirmed via the circular dichroism spectra.     

The One Step Synthesis of 2-(2-Bromo-5- methoxyphenyl)-5-(3-arylidene)-1,3-thiazolo[3,2-b]- 1,2,4-triazol-6-(5H)-ones and the Evaluation of the Anticonvulsant Activity

A smooth one-step synthesis of 2-(2-bromo-5-methoxyphenyl)-5-(3-arylidene)-1,3-thiazolo[3,2-b]-1,2,4-triazol-6-(5H)-ones (4a–n) is described. The newly prepared compounds are characterized by analytical and IR, ¹ H NMR, ¹³ C NMR, and FABMS spectral analysis. A few compounds are screened for anticonvulsant activity. Compounds 4i and 4n exhibit promising anticonvulsant activity and are recommended for further studies.     

Chemical constituents from Gueldenstaedtia verna and their anti-inflammatory activity

A new triterpenoid glycoside (1) and 15 known compounds (2–16) were isolated from the whole plants of Gueldenstaedtia verna. The new compound (1) was identified as complogenin 22-O-β-d-glucopyranoside by extensive spectroscopic techniques including 1D (¹H and ¹³C) and 2D NMR experiments (HSQC, HMBC and NOESY), HR-DART-MS and chemical methods. Most of the isolates were evaluated for their inhibitory activities on LPS-induced NO production in RAW 264.7 cells. The inhibitory effects of the active compounds, sulphuretin (8) and (22E,24S)-5α,8α-epidioxy-24-methyl-cholesta-6,9(11),22-trien-3β-ol (13), on the production of pro-inflammatory mediators (including IL-6, IL1β and PGE₂) were further estimated in vitro by ELISA in RAW 264.7 macrophages.     

Two new polyacetylene glycosides from the roots of Codonopsis tangshen Oliv.

Two new polyacetylene glycosides, tangshenyne A (1) and tangshenyne B (2), along with six known polyacetylenes were isolated from an 85% MeOH extract of the roots of Codonopsis tangshen Oliv. The chemical structures of the new compounds were determined on the basis of extensive spectroscopic analyses, including UV, IR, 1D and 2D NMR (¹H–¹H COSY, HSQC and HMBC) and HR-ESI-MS.     

A new ent-clerodane diterpenoid from Crassocephalum bauchiense Huch. (Asteraceae)

A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3′,5-dihydroxy-4′,5′,6,7,8-pentamethoxyflavone (2) and 4′,5-dihydroxy-3′,5′,6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC₅₀ = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially ¹H and ¹³C NMR, ¹H–¹H COSY, NOESY, HMBC and HR-ESI-MS.     

A new flavanone glycoside isolated from Tournefortia sibirica

A new flavanone glycoside, (2S)-dihydrooroxylin A 7-O-[β-D-apiosyl(1→2)]-β-D-glucoside (1), and four known compounds (2–5) were isolated from Tournefortia sibirica L. The chemical structures of these compounds were determined by 1?D and 2?D NMR and HR-ESI-MS spectra, and results were compared with data from the literature. These five compounds (1–5) were isolated from the family Boraginaceae for the first time. Anti-inflammatory effects of compounds (1–5) were evaluated in terms of inhibition of production of NO, TNF-α, and IL-6 in LPS-induced RAW 264.7 cells.     

Design,synthesis and biological evaluation of novel N1,N8-bis(((4-((5-aryl-1,3,4-oxadiazol-2-yl)methoxy)phenyl)amino)oxy)-1-naphthamide derivatives

A new series of 1,8-bis(4-((5-phenyl-1,3,4-oxadiazol-2-yl) methoxy)-substituted aryl) naphthalene-1,8-dicarboxamide derivatives (6a–j) were synthesized in the presence of POCl₃ and obtained good yields. All the synthesized novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, HRMS spectroscopic data and elemental analysis. All the synthesized compounds evaluated for their antibacterial and antifungal activities. The antibacterial activity screened against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli and used standard reference drug ciprofloxacin. The antifungal activity screened against two pathogenic fungal strains Aspergillus niger and Candida albicans used a reference standard drug Voriconazole. All these compounds (6a–j) demonstrate good antibacterial and antifungal activity. Among them, compounds 6h and 6c show highest antibacterial and antifungal activity.     

Synthesis and characterization of oxazine bearing pyridine scaffold as potential antimicrobial agents

A series of novel compounds 1-((1-(4-(2H-benzo[e][1,3]oxazin-3(4H)-yl)phenyl)ethylidene)amino)-6-((benzylidene)amino)-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles (7a–o) were synthesized by a sequence of multistep reactions. IR, ¹H NMR, ¹³C NMR, and mass spectral techniques were used to confirm the structures newly synthesized compounds. Antimicrobial activity of the title compounds (7a–o) was studied against strains of bacteria (Staphylococcus aureus and Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa) and fungi (Candida albicans, Aspergillus niger and Aspergillus clavatus) by serial dilution method. Compounds 7f and 7k exhibited significant antimicrobial activity.     

Pleiocarpumlignan A,a new dineolignan from Piper pleiocarpum Chang ex Tseng

Abstract

The investigation of chemical constituents from the whole plants Piper pleiocarpum Chang ex Tseng resulted in the isolation of one new dineolignan, pleiocarpumlignan A (1), along with one known benzoate derivative, trans-2,3-diacetoxy-1-[(benzoy1oxy)methyl]-cyclohexa-4,6-diene (2), and two known neolignans (3–4) as (±)-trans-dehydrodiisoeugenol (3), (7R,8R,3′S)-△^8′-3′,6′-dihydro-3′-methoxy-3,4-methylenedioxy-6′-oxo-8,3′,7,O,4′-lignan (4). Their structures were elucidated through extensive spectroscopic analyses including 1D, 2D NMR, HR-ESI-MS, and by comparison with the literature. All compounds (1–4) were firstly isolated from Piper pleiocarpum Chang ex Tseng. The ¹³C NMR spectra of 2 were completely assigned for the first time. Cytotoxic activities of these isolated compounds against five human cancer cell lines (including A-549, SMMC-7721, HL-60, MCF-7, and SW-480) were evaluated.     

New class of diethyl substituted phosphoramidimidates and phosphonimidates: synthesis,spectral characterization and antimicrobial activity

Abstract

A series of new class of diethyl N-2-hydroxyethyl-N'-substituted phosphoramidimidates 6(a–e) and diethyl P-morpholino-N-substituted phosphonimidates 6(f–j) was synthesized. The precursor intermediates, diethyl substituted phosphoramidites 3(a–b) were prepared initially by a reaction of various amines 1(a–b) and diethyl phosphorochloridite (2) and then they were treated by in situ with aromatic/alkyl azides through Staudinger reaction to accomplish title products. Structures of all the synthesized compounds were characterized by spectroscopic data such as IR, NMR (¹H, 13C, ³¹P), mass, and elemental analyses. The synthesized compounds were screened for their in vitro antimicrobial activity to understand their biological potency. The biological screening results disclosed that compounds 6b, 6c, 6e, 6g, 6h and 6j having potent antimicrobial activity against all the tested pathogens.     

Synthesis and biological activity of ethyl 2-(5-methyl-3-arylisoxazole-4-carboxamido)-4-alkylthiazole-5-carboxylate

A series of novel ethyl 2-(5-methyl-3-arylisoxazole-4-carboxamido)-4-alkylthiazole-5-carboxylates I-1-6 were synthesized. The structures of all target compounds were characterized by ¹H NMR, ¹³C NMR, IR, MS and elemental analyses. Their fungicidal and herbicidal activities were evaluated. The results of preliminary bioassays show that the title compounds I-4 possess 20–50% inhibition against most of the tested plants at the dosage of 150 g ai/ha, while the title compounds I-1-5 possess 32–58% inhibition against FusaHum graminearum, Thanatephorus cucumeris, Botrytis cinereapers and Fusarium oxysporum in vitro at the concentration of 100 mg/L.     

A new flavane acid from the fruits of Illicium verum

A new compound, illiciumflavane acid (1), along with 13 known compounds (2–14), were isolated from the fruits of Illicium verum Hook. F. Their structures were elucidated through various spectroscopic methods, including 1D NMR (¹H NMR, ¹³C NMR), 2D NMR (HMQC, HMBC and NOESY) and HRMS. The stereochemistry at the chiral centres was determined using CD spectrum as well as analyses of coupling constants and optical rotation data. Cytotoxicity evaluation of four compounds showed that illiciumflavane acid and (E)-1,2-bis(4-methoxyphenyl)ethene exhibited potential against A549 activities with IC₅₀ values of 4.63 μM and 9.17 μM, respectively.     

A Convenient One-Pot Synthesis of Some New 3-(2-Phenyl-6-(2-thienyl)-4-pyridyl)hydroquinolin-2-ones Under Microwave Irradiation and Their Antimicrobial Activities

A series of 3-(2-phenyl-6-(2-thienyl)-4-pyridyl)hydroquinolin-2-ones 4a–o were synthesized in high yields by a one–pot cyclocondensation reaction under Kröhnke's reaction conditions using 2-chloro-3-formyl quinoline 1a–c, 2-acetyl thiophene 2, and various N-phenacylpyridinium bromides 3a–e in a mixture of ammonium acetate and acetic acid by microwave irradiation. All the compounds have been characterized by elemental analysis, FT-IR, ¹H NMR, and ¹³C NMR spectral analysis. These compounds have been screened for their antimicrobial activities.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Novel synthesis of substituted N-(3-aryl-1,8-naphthyridin-2-yl) and N,N′-bis(3-aryl-1,8-naphthyridin-2-yl)benzene-1,4-diamines and 2-(4-((3-aryl-1,8-naphthyridin-2-yl)amino)phenyl)isoindoline-1,3-diones and their biological evaluation

A straightforward and highly efficient series of new substituted 3-aryl-1,8-naphthyridine derivatives 3a–e, 4a–e, and 6a–e were synthesized. Condensation dissimilar quantities of 2-chloro-3-aryl-1,8-naphthyridine 1a–e with benzene-1,4-diamine 2 and sodium ethoxide refluxing in ethanol solvent yielded the compounds 3a–e and 4a–e. The 2-(4-((3-aryl-1,8-naphthyridin-2-yl)amino)phenyl)isoindoline-1,3-diones 6a–e were obtained by treatment of compounds 3a–e with phthalic anhydride 5 in refluxing N,N-dimethylformamide is described. All synthesized compounds evaluated for their antimicrobial activity. The structures of the compounds have been proven on the established of spectral (IR, ¹H NMR, and ¹³C NMR) data and elemental analyses. The reaction will be characterized by good efficacy, easy workup, simple purification of the products, and availability of catalyst.     

A new indole-alkaloid and a new phenolic-glycoside with cytotoxic activity from Strychnos fendleri

A new indole alkaloid strychnosinol (1) and a new phenolic-glycoside (2) were isolated from the bark and leaves of Strychnos fendleri Sprague & Sandwith, together with six known compounds reported for the first time in this species. The structures of these compounds were determined on the basis of spectroscopic data; mainly those obtained by using ¹H and ¹³C NMR (1D and 2D) and mass spectrometry. Strychnosinol (1) and the phenolic glycoside (2) together with compounds 3–8 were evaluated for cytotoxicity against a panel of five tumour cell lines; IC₅₀ values between 0.090 and 0.227 μM for the human tumour cell lines were observed for compound 2.