Synthesis of Pentafluorophenyl‐ and Pyridinyl‐3 Allenes

The allenes 1,2,3,4,5‐pentafluoro‐6‐(3‐phenylpropa‐1,2‐dienyl)benzene 4 , 3‐(3‐phenylpropa‐1,2‐dienyl)pyridine 11 and 3‐(3‐(pyridine‐3‐yl)propa‐1,2‐dienyl)pyridine 17 and the acetylenes 5 , 12 and 16 were obtained by reduction of the corresponding propargylic acetates 3 , 10 and 15 by Samarium(II) iodide in the presence of Pd(0). Base‐promoted isomerisation of acetylene 12 provided allene 11 in a yield of 80%. 1‐(Pentafluorophenyl)‐3‐phenylprop‐2‐yn‐1‐ol 2 was prepared from phenylacetylene and pentafluorobenzaldehyde. The condensation of nicotinaldehyde with trimethylsilylacetylene gave the 3‐(trimethylsilyl)‐1‐(pyridine‐3‐yl)prop‐2‐yn‐1‐ol 7 . The removal of the silyl group of 7 to acetylene 8 was done in basic conditions. The Pd catalysed condensation of the acetylene 8 with iodobenzene gave 3‐phenyl‐1‐(pyridine‐3‐yl)prop‐2‐yn‐1‐ol 9 . The Pd catalysed condensation of 8 with 3‐bromopyridine gave the 1,3‐dipyridin‐3‐yl‐prop‐2‐yn‐1‐ol 14 . The propargylic alcohols 2 , 9 and 14 were converted to the acetates 3 , 10 and 15 with acetic anhydride‐pyridine.     

Synthesis,structure and in vitro cytotoxicity testing of some 1,3,4‐oxadiazoline derivatives from 2‐hydroxy‐5‐iodobenzoic acid

The syntheses of nine new 5‐iodosalicylic acid‐based 1,3,4‐oxadiazoline derivatives starting from methyl salicylate are described. These compounds are 2‐[4‐acetyl‐5‐methyl‐5‐(3‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6a ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6b ), 2‐(4‐acetyl‐5‐methyl‐5‐phenyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl)‐4‐iodophenyl acetate, C₁₉H₁₇IN₂O₄ ( 6c ), 2‐[4‐acetyl‐5‐(4‐fluorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆FIN₂O₄ ( 6d ), 2‐[4‐acetyl‐5‐(4‐chlorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆ClIN₂O₄ ( 6e ), 2‐[4‐acetyl‐5‐(3‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6f ), 2‐[4‐acetyl‐5‐(4‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6g ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐methylphenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6h ) and 2‐[5‐(4‐acetamidophenyl)‐4‐acetyl‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6i ). The compounds were characterized by mass, ¹H NMR and ¹³C NMR spectroscopies. Single‐crystal X‐ray diffraction studies were also carried out for 6c , 6d and 6e . Compounds 6c and 6d are isomorphous, with the 1,3,4‐oxadiazoline ring having an envelope conformation, where the disubstituted C atom is the flap. The packing is determined by C—H…O, C—H…π and I…π interactions. For 6e , the 1,3,4‐oxadiazoline ring is almost planar. In the packing, Cl…π interactions are observed, while the I atom is not involved in short interactions. Compounds 6d , 6e , 6f and 6h show good inhibiting abilities on the human cancer cell lines KB and Hep‐G2, with IC₅₀ values of 0.9–4.5 µM.     

Theoretical studies on geometry,solvent effect,and photochromic mechanism of two bis‐heterocyclic compounds containing pyrazolone ring

Two bis‐heterocyclic compounds containing pyrazolone ring, 1‐phenyl‐3‐methyl‐4‐(6‐hydro‐4‐amino‐5‐sulfo‐2,3‐pyrazine)‐pyrazole‐5‐one and 1‐phenyl‐3‐methyl‐4‐(6‐hydro‐4‐methylamino‐5‐sulfo‐2,3‐pyrazine)‐pyrazole‐5‐one, are investigated to gain a deeper insight into their geometries and photochromic mechanism by applying density functional theory. The solvent effects are simulated using the polarizable continuum model of the self‐consistent reaction field theory. Bader's atom‐in‐molecule theory is used to investigate the nature of hydrogen bonds. The data of energy, dipole moments, and the condensed Fukui functions have been calculated to assess the stability and reactivity of the title compounds. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Structure elucidation and NMR assignments for curcuminoids from the rhizomes of Curcuma longa

Thirteen curcuminoids (1–13) were isolated from the rhizomes of Curcuma longa. Among them, 1,5‐dihydroxy‐1,7‐bis(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (1), 1,5‐dihydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)‐7‐(4‐hydroxyphenyl)‐4,6‐heptadiene‐3‐one (2), 1,5‐dihydroxy‐1‐(4‐hydroxyphenyl)‐7‐(4‐hydroxy‐3‐methoxyphenyl)‐4,6‐heptadiene‐3‐one (3), and 3‐hydroxy‐1,7‐bis‐(4‐hydroxyphenyl)‐6‐heptene‐1,5‐dione (4) are new compounds, and 1‐(4‐hydroxyphenyl)‐7‐(3, 4‐dihydroxyphenyl)‐1, 6‐heptadiene‐3, 5‐dione (5) is isolated from natural sources for the first time. The structures of these compounds were elucidated by extensive spectroscopic analyses, especially 1D and 2D NMR spectroscopy. The ¹³C NMR data and complete ¹H and ¹³C NMR assignments of some known compounds are reported for the first time. In addition, the errors of ¹H and ¹³C assignments reported in the literature were corrected. Copyright © 2009 John Wiley & Sons, Ltd.     

New Anthraquinone Derivatives as Electrochemical Redox Indicators for the Visualization of the DNA Hybridization Process

Interactions of dsDNA and ssDNA, at the surface of gold and silver electrodes, with three novel anthraquinone derivatives: 3‐(9′,10′‐dioxo‐9′,10′‐dihydro‐anthracen‐1‐yl)‐7,11‐di(carboxymethyl)‐3,7,11‐triazatridecanedioic acid, (AQ‐1); 1‐(9′,10′‐dioxo‐9′,10′‐dihydro‐anthracen‐1yl)‐9‐carboxymethyl‐5‐methyl‐1,5,9‐triazaundecanoicacid, (AQ‐2); and N‐(2‐(9,10‐dioxo‐9,10‐dihydro‐anthracen‐1‐ylamino)ethyl)‐2‐(1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecan‐7‐yl)acetamide, (AQ‐3) are studied. These derivatives are well soluble in water and phosphate buffer solutions. The square wave voltammetric behavior of these redox indicators is described and the parameters of interactions with DNA are reported. It is also pointed out that these compounds can be employed as the hybridization indicators. The difference in the binding ability of the particular redox indicator to single and double stranded DNA can be used for the detection of the complementary nucleic acids.     

Radical Cyclization of Fluorinated 1,3‐Dicarbonyl Compounds with Dienes Using Manganese(III) Acetate and Synthesis of Fluoroacylated 4,5‐Dihydrofurans

Radical cyclizations of fluorinated 1,3‐dicarbonyl compounds with dienes mediated by Mn(OAc)₃ afforded 4,5‐dihydrofurans containing difluoroacetyl, trifluoroacetyl, or heptafluorobutanoyl groups in good‐to‐excellent yields. Additionally, 2‐(difluoromethyl)‐4,5‐dihydrofurans and a 4,7‐dihydrooxepin derivative were obtained as unexpected products in the reaction of 4,4‐difluoro‐1‐phenylbutane‐1,3‐dione with 1,3‐diphenylbuta‐1,3‐diene. The radical cyclization of symmetrical dienes such as 2,3‐dimethylbuta‐1,3‐diene and 1,4‐diphenylbuta‐1,3‐diene with 1,3‐diketones furnished the corresponding products in low yields. However, treatment of 1‐phenylbuta‐1,3‐diene with 1,3‐dicarbonyl compounds afforded 4,5‐dihydrofurans containing fluoroacyl groups. The radical cyclizations with 3‐methyl‐1‐phenylbuta‐1,3‐diene and 1,3‐diphenylbuta‐1,3‐diene led to 4,5‐dihydrofurans in good yields, since Me and Ph groups at C(3) of these dienes increase the stability of the radical intermediate.     

Synthesis of Arylnaphthoquinones and Their Reactions with o‐Substituted Primary Aromatic Amines

Cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1a‐d with a number of different dienes, namely 2,3‐dimethylbutadiene; 1,4‐diphenylbutadiene and anthracene yield 2‐aryl‐6,7‐dimethyl‐1,4‐ naphthoquinones 3a,b ; 2,5,8‐triphenyl‐1,4‐naphthoquinone 4 and 2‐aryl‐1,4,9,10‐tetrahydro‐9,10‐o‐benzoanthracene‐1,4‐dione 5 , respectively were investigated. In addition, the cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1d,e with 2,3‐dimethylbutadiene was also investigated to yield 2‐aryl‐5,8‐dihydro‐6,7‐dimethyl‐1,4‐naphthohydroquinones 2a,b . Cyclocondensation reactions of Diels‐Alder adducts 2b, 3b, 5a with ethylenediamine, o‐substituted primary aromatic amines gave quinoxaline, phenazine, phenoxazine and phenothiazine ocyclic derivatives 6–14.     

Combination of capillary electrophoresis and molecular modeling to study the enantiomer affinity pattern between β‐blockers and anionic cyclodextrin derivatives in a methanolic and water background electrolyte

In order to have deep insights into the mechanisms of enantiomer affinity pattern in both aqueous and non‐aqueous systems, an approach combining capillary electrophoresis and molecular modeling was undertaken. A chiral β‐blocker; acebutolol, was enantioseparated in aqueous capillary electrophoresis and non‐aqueous capillary electrophoresis using two anionic β‐cyclodextrin derivatives. The enantiomer affinity pattern of acebutolol was found to be opposite when an aqueous background electrolyte was replaced with non‐aqueous background electrolyte in the presence of heptakis(2,3‐di‐O‐acetyl‐6‐sulfo)‐β‐cyclodextrin but remained the same in the presence of heptakis(2,3‐di‐O‐methyl‐6‐sulfo)‐β‐cyclodextrin. Molecular docking of acebutolol into two β‐cyclodextrin derivatives indicated two distinct binding modes called ‘up’ and ‘down’ conformations. After structure optimization by molecular dynamics and energy minimization, both enantiomers of acebutolol were preferred to the ‘up’ conformation with heptakis(2,3‐di‐O‐methyl‐6‐sulfo)‐β‐cyclodextrin while ‘down’ conformation with heptakis(2,3‐di‐O‐acetyl‐6‐sulfo)‐β‐cyclodextrin. The further calculation of the complex energy with solvent effect indicated that heptakis(2,3‐di‐O‐acetyl‐6‐sulfo)‐β‐cyclodextrin had higher affinity to S‐acebutolol than R‐acebutolol in non‐aqueous capillary electrophoresis while it showed better binding to R‐acebutolol in aqueous capillary electrophoresis. However, the heptakis(2,3‐di‐O‐methyl‐6‐sulfo)‐β‐cyclodextrin bound better to R‐acebutolol in both aqueous and non‐aqueous capillary electrophoresis, implying that the binding mode played more important role in chiral separation of heptakis(2,3‐di‐O‐methyl‐6‐sulfo)‐β‐cyclodextrin while the solvent effect had prevailing impact on heptakis(2,3‐di‐O‐acetyl‐6‐sulfo)‐β‐cyclodextrin.     

Synthesis and electrochromic properties of triphenylamine containing copolymers: Effect of π‐bridge on electrochemical properties

In this study, a series of benzotriazole (BTz) and triphenylamine (TPA)‐based random copolymers; poly4‐(5‐(2‐dodecyl‐7‐methyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)thiophen‐2‐yl)‐N‐(4‐(5‐methylthiophen‐2‐yl)phenyl)‐N‐phenylaniline ( P1 ), poly4′‐(2‐dodecyl‐7‐methyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)‐N‐(4′‐methyl‐[1,1′‐biphenyl]‐4‐yl)‐N‐phenyl‐[1,1′‐biphenyl]‐4‐amine ( P2 ), and poly4‐(5′‐(2‐dodecyl‐7‐(5‐methylthiophen‐2‐yl)?2H‐benzo[d][1,2,3]triazol‐4‐yl)‐[2,2′‐bithiophen]‐5‐yl)‐N‐(4‐(5‐methylthiophen‐2‐yl)phenyl)‐N‐phenylaniline ( P3 ) were synthesized to investigate the effect of TPA unit and π‐bridges on electrochemical and spectroelectrochemical properties of corresponding polymers. The synthesis was carried out via Stille coupling for P1 , P3 , and Suzuki coupling for P2 . Electrochemical and spectral results showed that P1 has an ambipolar character, in other words it is both p‐type and n‐type dopable, whereas P2 and P3 have only p‐doping property. Effect of different π‐bridges and TPA unit on the HOMO and LUMO energy levels, switching time, and optical contrast were discussed. All polymers are promising materials for electrochromic devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 537–544     

Substituted 2,2′‐Bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl Complexes of Zinc

The condensation reaction of 2,2′‐diamino‐4,4′‐dimethyl‐6,6'‐dibromo‐1,1′‐biphenyl with 2‐hydroxybenzaldehyde as well as 5‐methoxy‐, 4‐methoxy‐, and 3‐methoxy‐2‐hydroxybenzaldehyde yields 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyl ( 1a ) as well as the 5‐, 4‐, and 3‐methoxy‐substituted derivatives 1b , 1c , and 1d , respectively. Deprotonation of substituted 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls with diethylzinc yields the corresponding substituted zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls ( 2 ) or zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyls ( 3 ). Recrystallization from a mixture of CH₂Cl₂ and methanol can lead to the formation of methanol adducts. The methanol ligands can either bind as Lewis base to the central zinc atom or as Lewis acid via a weak O–H ··· O hydrogen bridge to a phenoxide moiety. Methanol‐free complexes precipitate as dimers with central Zn₂O₂ rings.     

Triarylamine N‐functionalized 3,6‐linked carbazole main chain polymers and copolymers: Preparation and physical properties

The preparation of triarylamine N‐functionalized 3,6‐linked carbazole homopolymers as well as alternating copolymers with 2,5‐diphenyl‐[1,3,4]oxadiazole and benzo[1,2,5]thiadiazole was undertaken using Suzuki cross‐coupling polymerization procedures associating 3,6‐bis(4,4,5,5‐tetramethyl‐[1,3,2]dioxaborolan‐2‐yl)‐9‐(bis[4‐(2‐butyl‐octyloxy)‐phenyl]‐amino‐phen‐4‐yl)‐carbazole and, respectively, 3,6‐dibromo‐9‐(bis[4‐(2‐butyl‐octyloxy)‐phenyl]‐amino‐phen‐4‐yl)‐carbazole, 2,5‐bis(4‐bromo‐phenyl)‐[1, 3,4]oxadiazole, and 4,7‐dibromo‐benzo[1,2,5]thiadiazole. Both the carbazole homopolymer and alternating copolymer with 2,5‐diphenyl‐[1,3,4]oxadiazole were found as wideband gap materials emitting in the blue part of the electromagnetic spectrum while the carbazole alternating copolymer with 4,7‐benzo[1,2,5]thiadiazole had a narrower band gap and emitted in the orange part of the electromagnetic spectrum. The new polymers are thermally stable up to 300 °C. A discussion of the electrochemical and optical properties of the new polymers is presented. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5957–5967, 2007.     

Quinolone analogues 2. A facile synthesis of novel 3‐substituted 1‐alkyl‐4‐oxo‐1,4‐dihydropyridazino[3,4‐b]quinoxalines

The reaction of the 2‐(1‐alkylhydrazino)‐6‐chloroquinoxaline 4‐oxides 1a,b with diethyl acetone‐dicarboxylate or 1,3‐cyclohexanedione gave ethyl 1‐alkyl‐7‐chloro‐3‐ethoxycarbonylmethylene‐1,5‐dihydropyridazino[3,4‐b]quinoxaline‐3‐carboxylates 5a,b or 6‐alkyl‐10‐chloro‐1‐oxo‐1,2,3,4,6,12‐hexahydroquinoxalino[2,3‐c]cinnolines 7a,b , respectively. Oxidation of compounds 5a,b with nitrous acid afforded the ethyl 1‐alkyl‐7‐chloro‐3‐ethoxycarbonylmethylene‐4‐hydroxy‐1,4‐dihydropyridazino‐[3,4‐b]quinoxaline‐4‐carboxylates 9a,b , whose reaction with base provided the ethyl 2‐(1‐alkyl‐7‐chloro‐4‐oxo‐1,4‐dihydropyridazino[3,4‐b]quinoxalin‐3‐yl)acetates 6a,b , respectively. On the other hand, oxidation of compounds 7a,b with N‐bromosuccinimide/water furnished the 4‐(1‐alkyl‐7‐chloro‐4‐oxo‐1,4‐dihydropyridazino[3,4‐b]quinoxalin‐3‐yl)butyric acids 8a,b , respectively. The reaction of compound 8a with hydroxylamine gave 4‐(7‐chloro‐4‐hydroxyimino‐1‐methyl‐1,4‐dihydropyridazino[3,4‐b]quinoxalin‐3‐yl)‐butyric acid 12 .     

Silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano‐catalyst for highly efficient synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues having potent antigiardial activity

The preparation, characterization and application of silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano catalyst for synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues is described. STCATSC is fully characterized by different microscopic, spectroscopic and physical techniques, including scanning electron microscopy (SEM), transmission, X‐ray diffraction (XRD), Energy‐dispersive X‐ray spectroscopy (EDS), thermogravimetric analysis (TGA), FT‐IR and inductively coupled plasma (ICP) analysis. This catalyst is used to prepare the new 1,2,3‐triazolyl‐based metronidazole hybrid analogues. The ‘Click’ Huisgen cycloaddition reaction of 2‐methyl‐5‐nitro‐1‐prop‐2‐ynyl‐1H‐imidazole with diverse β‐azidoalcohols in a THF‐water media at R.T. provides the products in good to excellent yields using STCATSC. STCATSC is proved to be a stable, low cost, reusable and environmentally benign hybrid catalyst. Products are in vitro tested against Giardia lamblia (G. lamblia) in which determined that all compounds exhibit varied promising antigiardial activity compare to metronidazole as a reference drug. Among the products, 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐phenethoxypropan‐2‐ol and 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐(3‐phenylpropoxy)propan‐2‐ol are demonstrated to exhibit the potent antigiardial activity even stronger than metronidazole.     

Norlignans and Phenylpropanoids from Metasequoia glyptostroboides Hu et Cheng

Five new compounds, i.e., the three new norlignans metasequirins G–I ( 1 – 3 ) and the two new phenylpropanoids 7‐(3‐ethoxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐ethoxy‐5‐methoxyphenyl)propane‐1,2,3‐triol; 4 ) and 7‐(3‐hydroxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐hydroxy‐5‐methoxy‐phenyl)propane‐1,2,3‐triol; 5 ), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng . Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D‐ and 2D‐NMR and HR‐ESI‐MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.     

Single component transparent free‐standing films based on polyhedral octasilicate‐core dendrimers bearing carbazole terminal groups and their emission properties

9H‐carbazole‐9‐ethyl and 9H‐carbazole‐9‐hexyl‐terminated polyhedral octasilicate (OS)‐core dendrimers, denoted as OS‐C2‐Cz and OS‐C6‐Cz, respectively, were prepared by ring‐opening reaction and subsequent condensation of octakis(propenyl succinicanhydrido)polyhedral octasilicate (OS‐SA) with 9H‐carbazole‐9‐ethanol (Cz‐C2‐OH) and 9H‐carbazole‐9‐hexanol (Cz‐C6‐OH), respectively. Both the dendrimers formed optical transparent coating films. In particular, the coating film of OS‐C2‐Cz was easily peeled off from a substrate and formed a free‐standing film. The results of X‐ray diffraction and differential scanning calorimeter suggest that the films of OS‐C2‐Cz and OS‐C6‐Cz were amorphous. Thermogravimetric analysis of OS‐C2‐Cz and OS‐C6‐Cz showed 10 wt % weight losses at 374 and 383 °C, respectively. Photoluminescence property revealed that the carbazole group in OS‐C2‐Cz is prevented the excimer formation, while the carbazole group in OS‐C6‐Cz formed the excimer. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 628–633     

Perchlorate‐Free Pyrotechnic Formulations Utilizing Energetic Chlorine Donors: 1‐CDN, 11‐CDN, 13‐CDN

Several novel materials were investigated as energetic chlorine donors, specifically for the preparation of perchlorate‐free pyrotechnic formulations with low‐smoke output. The novel compounds, 2‐chloromethyl‐2‐methyl‐5,5‐dinitro‐1,3‐dioxane (1‐CDN), 2,2‐bis(chloromethyl)‐5,5‐dinitro‐1,3‐dioxane (13‐CDN), and 2‐(dichloromethyl)‐2‐methyl‐5,5‐dinitro‐1,3‐dioxane (11‐CDN), were formulated with a variety of fuels and oxidizers and their resulting colored flames analyzed for color quality. The preparation and preliminary characterization of these energetic chlorine donors are described.     

Two New Kaempferol Glycosides from Androsace umbellata

Two new kaempferol glycosides, 5‐hydroxy‐2‐(4‐hydroxyphenyl)‐4‐oxo‐7‐(α‐L ‐rhamnopyranosyloxy)‐4H‐chromen‐3‐yl 2‐O‐acetyl‐3‐O‐β‐D ‐glucopyranosyl‐α‐L ‐rhamnopyranoside ( 1 ) and 5‐hydroxy‐2‐(4‐hydroxyphenyl)‐4‐oxo‐7‐(α‐L ‐rhamnopyranosyloxy)‐4H‐chromen‐3‐yl β‐D ‐glucopyranosyl‐(1→2)‐6‐O‐[(2E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoyl]‐β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐glucopyranoside ( 2 ), along with ten known compounds, were isolated from the 95% EtOH extract of the whole plant of Androsace umbellata. The structures of the new glycosides were determined on the basis of detailed spectroscopic analyses, including 1D‐ and 2D‐NMR, MS, and chemical methods.     

Five New Eremophilane Sesquiterpenes from Ligularia przewalskii

Five new eremophilane‐type sesquiterpenes, 3β‐(acetyloxy)‐7‐hydroxynoreremophila‐6,9‐dien‐8‐one ( 1 ), 8β‐hydroxy‐2‐dehydroxyliguhodgsonal ( 2 ), 3β‐(acetyloxy)‐11‐methoxy‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 3 ), 3β‐(acetyloxy)‐11‐(2′‐methylbutanoyloxy)‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 4 ), and 3β‐(acetyloxy)‐6α‐hydroxyligularenolide ( 5 ), along with the three known compounds 6 – 8 , were isolated from the roots of Ligularia przewalskii. The structures of the new compounds were elucidated through spectral studies including HR‐EI‐MS, IR, and NMR data.     

Synthesis and Properties of Brominated 6,6'-Dimethyl-[2,2'-bi-1H-indene]-3,3'-diethyl-3,3'-dihydroxy-1,1 '-diones

Photochromic 6‐bromomethyl‐6′‐methyl‐[2,2′‐bi‐1H‐indene]‐3,3′‐diethyl‐3,3′‐dihydroxy‐1,1′‐dione ( 2 ), 6,6′‐ bis(bromomethyl)‐[2,2′‐bi‐1H‐indene]‐3,3′‐diethyl‐3,3′‐dihydroxy‐1,1′‐dione ( 3 ) and 6,6′‐bis(dibromomethyl)‐[2,2′‐ bi‐1H‐indene]‐3,3′‐diethyl‐3,3′‐dihydroxy‐1,1′‐dione ( 4 ) have been synthesized from 6,6′‐dimethyl‐[2,2′‐bi‐1H‐ indene]‐3,3′‐diethyl‐3,3′‐dihydroxy‐1,1′‐dione ( 1 ). The single crystal of 4 was obtained and its crystal structure was analyzed. The results indicate that in crystal 4 , molecular arrangement is defective tightness compared with its precursor 1 . Besides, UV‐Vis absorption spectra in CH₂Cl₂ solution, photochromic and photomagnetic properties in solid state of 2 , 3 and 4 were also investigated. The results demonstrate that when the hydrogen atoms in the methyl group on the benzene rings of biindenylidenedione were substituted by bromines, its properties could be affected considerably.