REACTIONS WITH 2- (THIOCYANATOACETYL) AND 2-(SELENOCYANATOACETYL)-2′-BENZOFURAN: SYNTHESIS OF SOME NEW THIADIAZOLINE,SELENODIAZOLINE, THIA-DIAZOLO[2,3-b]QUINAZOLINE AND ARYLAZOTHIAZOLE DERIVATIVES

Abstract

Several new thiadiazoline, selenodiazoline, thiadiazolo[2, 3-b]quinazoline and arylazothiazole derivatives were synthesized via the reaction of 2- (thiocyanatoacetyl)-2′-benzofuran with arendiazonium chlorides, nitrous acid, acetic anhydride, benzoyl chloride, diazotised anthranilic acid and its methyl ester and thiourea. The structures of the newly synthesized derivatives were established on the basis of elemental analyses and spectral data studies.     

Effective Conversion of Three Diacetyl‐C‐(β‐D‐Glycopyranosyl) Phloroglucinols to Spiroketal Derivatives by Refluxing in Water

Refluxing of diacetylphloroglucinol C‐β‐D‐gluco‐, ‐galacto‐, and ‐allopyranosides in water for 1 d gave two kinds of spiroketal derivatives in total yields of 77%, 74%, and 64%, respectively. The structure and stereochemistry of the six new spiro(benzofuran‐[2H]pyran and ‐[2H]furan) derived from galactoside and alloside were verified by NMR analysis. The production ratios of the spiro derivatives were measured by HPLC analysis at regular time intervals. Since the majority of spiro(benzofuran‐[2H]furan) were produced after 8 to 12 h of refluxing and most spiro(benzofuran‐[2H]pyran) produced after 2 d of refluxing, it is assumed that formation of spirofuran and spiropyran is a kinetic‐ and thermodynamic‐controlled reaction, respectively.     

Solid-phase synthesis: a linker for side-chain anchoring of arginine

A new linker based on a chroman system is described for the side-chain anchoring of Arg and other guanidine-containing molecules. The system is compatible with the Fmoc/tBu solid-phase strategy, because the release of the final product is achieved by treatment with TFA in the presence of scavengers.     

Formation of benzofuran and chlorobenzofuran from 1,3‐dichloropropene: A quantum chemical investigation

We present a quantum chemical investigation of benzofuran and cholorobenzofuran formation mechanisms during the combustion of 1,3‐dichloropropene. Density functional theory and Gaussian‐n thermochemical methods are used to propose detailed mechanistic reaction pathways. These calculations indicate that oxidation of phenylvinyl radical intermediates and subsequent ring closure are key mechanistic pathways in the formation of benzofuran and chlorobenzofuran. Thermochemical and kinetic parameters presented herein will assist in further elucidation of dioxin formation mechanisms from thermolyses of hydrocarbon moieties. © 2015 Wiley Periodicals, Inc.     

Constituents of the Leaves and Stem Bark of Aglaia foveolata

The previously known potent cytotoxic agent silvestrol (1) (0.002% w/w yield) and five new flavagline derivatives (2-6) were isolated from the leaves of Aglaia foveolata collected in Indonesia. The new compound 5 has an unprecedented cyclic amide moiety in its cyclopenta[b]benzopyran skeleton, while compound 6 is a novel benzo[b]oxepine derivative in which the oxepine ring is cleaved. Pyramidatine (7), a biogenetic precursor of the new flavaglines 2-6, was isolated from the leaf extract investigated. Silvestrol was also isolated from the stem bark of A. foveolata (yield of 0.02% w/w) along with a new baccharane-type triterpenoid (8). The structures of the new compounds were elucidated on the basis of their NMR and mass spectrometric data. All new compounds isolated were tested against a panel of cancer cell lines, but only compound 2 was cytotoxic (IC₅₀ range=1.4-1.8 μM), and is the first member of the cyclopenta[b]benzopyran class found to exhibit this type of activity. Compound 2 also showed significant NF-κB inhibitory activity in an Elisa assay (IC₅₀=0.37 μM).     

Novel Thiosemicarbazone Derivatives: In Vitro and In Silico Evaluation as Potential MAO-B Inhibitors

MAO-B inhibitors are frequently used in the treatment of neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Due to the limited number of compounds available in this field, there is a need to develop new compounds. In the recent works, it was shown that various thiosemicarbazone derivatives show hMAO inhibitory activity in the range of micromolar concentration. It is thought that benzofuran and benzothiophene structures may mimic structures such as indane and indanone, which are frequently found in the structures of such inhibitors. Based on this view, new benzofuran/benzothiophene and thiosemicarbazone hybrid compounds were synthesized, characterized and screened for their hMAO-A and hMAO-B inhibitory activity by an in vitro fluorometric method. The compounds including methoxyethyl substituent (2b and 2h) were found to be the most effective agents in the series against MAO-B enzyme with the IC₅₀ value of 0.042 ± 0.002 µM and 0.056 ± 0.002 µM, respectively. The mechanism of hMAO-B inhibition of compounds 2b and 2h was investigated by Lineweaver–Burk graphics. Compounds 2b and 2h were reversible and non-competitive inhibitors with similar inhibition features as the substrates. The K_i values of compounds 2b and 2h were calculated as 0.035 µM and 0.046 µM, respectively, with the help of secondary plots. The docking study of compound 2b and 2h revealed that there is a strong interaction between the active sites of hMAO-B and analyzed compound.     

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.     

微波促进芳酮(芳醛)的烃基化反应

以PEG-400和K2CO3为催化剂,微波辐射下,对羟基苯甲醛、香兰醛、水杨醛与α-溴代苯乙酮,α-溴代联苯乙酮反应,较高产率(70%~77%)地得到了O-烃基化产物(3a~3d)和环缩合产物(4a,4b)。3和4的结构经1H NMR和IR表征。