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The mass spectrometric behaviour of four cis‐ and trans‐1a,3‐disubstituted‐1,1‐dichloro‐4‐formyl‐1a,2,3,4‐tetrahydro‐1H‐azirino [1, 2‐a][1,5]benzodiazepines has been studied with the aid of mass‐analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino [1,2‐b][1,3] benzimidazole ions. These azirino [1,2‐a][1,5]‐benzodiazepimes can also eliminate HCl, or Cl plus HCl simultaneously to undergo a ring enlargement rearrangement to yield 1,6‐benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions. 相似文献
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N‐benzimidazol‐2‐yl imidate type 1 reacts with thiourea, carbon disulfide, cyanamide, and hydrazide to give, respectively, [1,2‐a] benzimidazolo‐1,3,5‐triazin‐2‐thione 2 , [1,2‐a] benzimidazolo‐1,3,5‐thiadiazin‐2‐thione 3 , [1,2‐a] benzimidazolo‐1,3,5‐triazin‐2‐amine 4 , and [1,2‐a] benzimidazol‐2‐yl amidrazone 5 with good yields. Structures elucidation of all newly synthesized heterocyclic compounds was based on the data of IR, 1H NMR, 13C NMR, elemental analysis, and MS of some products. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:279–283, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20618 相似文献
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Tomas Rozek John H. Bowie Brian W. Skelton Allan H. White 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o431-o432
The Diels–Alder reaction between 5‐hydroxy‐1,4‐naphthoquinone and 5,5‐dimethyl‐3‐vinyl‐1,2‐cyclohexadienyl acetate by endo addition gives the title compound, C22H22O5, in 68% yield. This racemic diastereoisomer has the opposite regiochemistry to ochromycinone analogues produced previously and may allow access to a new type of anticancer‐active saquayamycin analogue. 相似文献
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Javier Arranz‐Andrs Rosario Benavente Begoa Pea Ernesto Prez María L. Cerrada 《Journal of Polymer Science.Polymer Physics》2002,40(17):1869-1880
Several blends, covering the entire range of compositions, of a metallocenic ethylene‐1‐octene copolymer (CEO) with a multiphasic block copolymer, propylene‐b‐(ethylene‐co‐propylene) (CPE) [composed of semicrystalline isotactic polypropylene (iPP) and amorphous ethylene‐co‐propylene segments], have been prepared and analyzed by differential scanning calorimetry, X‐ray diffraction, optical microscopy, stress‐strain and microhardness measurements, and dynamic mechanical thermal analysis. The results show that for high CEO contents, the crystallization of the iPP component is inhibited and slowed down in such a way that it crystallizes at much lower temperatures, simultaneously with the crystallization of the CEO crystals. The mechanical results suggest very clearly the toughening effect of CEO as its content increases in the blends, although it is accompanied by a decrease in stiffness. The analysis of the viscoelastic relaxations displays, first, the glass transition of the amorphous blocks of CPE appearing at around 223 K, which is responsible for the initial toughening of the plain CPE copolymer in relation to iPP homopolymer. Moreover, the additional toughening due to the addition of CEO in the blends is explained by the presence of the β relaxation of CEO that appears at about 223 K. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1869–1880, 2002 相似文献
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Glen W. Spears Kiyoshi Tsuji Takashi Tojo Hiroaki Nishimura Takashi Ogino 《Journal of heterocyclic chemistry》2002,39(4):799-804
The novel title compounds have been prepared in high yield by an optimized amide coupling followed by a Dieckmann cyclization. Additionally, this new route is amenable to preparative scale synthesis. 相似文献
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Laurence Prat Vincent Levacher Georges Dupas Guy Quguiner Jean Bourguignon Ronan Bureau Cyril Daveu 《Journal of heterocyclic chemistry》2000,37(4):767-771
The synthesis of N‐methyl‐4‐pyridyl‐1,2,3,4‐tetrahydroisoquinolines (6a,b,c) was achieved via a Pictet‐Spengler cyclization of an activated amino group derivatized in a carbamate form. The obtained compounds have been designed as potential serotonin analogs. 相似文献
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Siyu Tu Se Hye Kim Jojo Joseph Prof. David A. Modarelli Prof. Jon R. Parquette 《Chemphyschem》2013,14(8):1609-1617
The construction of an n–p heterojunction through the self‐assembly of a dyad based on tetraphenylporphyrin (TPP) and 1,4,5,8‐naphthalenedimide (NDI) ( 1 ) is described. Proton transfer from the lysine head group of 1 to the porphyrin ring occurs concomitantly with self‐assembly into 1D nanorods in CHCl3. TEM and AFM studies showed that the nanorods are formed by the lateral and vertical fusion of multilameller vesicles into networks and hollow ribbons, respectively. These intermediate structures transitioned to nanorods over the course of 4–6 days. Time‐resolved spectroscopy revealed that photoinduced charge separation occurs with rate constants that depend on the nature of the aggregation. 相似文献
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Soichiro Nakatsuka Yusuke Watanabe Yoshinobu Kamakura Satoshi Horike Daisuke Tanaka Takuji Hatakeyama 《Angewandte Chemie (International ed. in English)》2020,59(4):1435-1439
A triphosphaazatriangulene (H3L) was synthesized through an intramolecular triple phospha‐Friedel–Crafts reaction. The H3L triangulene contains three phosphinate groups and an extended π‐conjugated framework, which enables the stimuli‐responsive reversible transformation of [Cu(HL)(DMSO)?(MeOH)]n, a 3D‐MOF that exhibits reversible sorption characteristics, into (H3L?0.5 [Cu2(OH)4?6 H2O] ?4 H2O), a 1D‐columnar assembled proton‐conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10?3 S cm?1 at 95 % relative humidity and 60 °C. 相似文献
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A series of 3a,5‐diaryl‐1,3‐diphenyl‐3a,4,5,6‐tetrahydro‐3H‐1,2,4‐triazolo[4,3‐a][1,5]benzo‐diazepines was synthesized by the cycloaddition reactions of 2,4‐diaryl‐2,3‐dihydro‐1H‐1,5‐benzo‐diazepines and N‐phenylbenzonitrileimine generated from N‐phenylbenzenecarbohydrazonic chloride in the presence of triethylamine in anhydrous tetrahydrofuran. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:557–559, 2001 相似文献
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Vyacheslav S. Grinev Alevtina Yu. Egorova 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(8):880-883
Molecules of the title compound, C16H14N2O, a potential plant‐growth regulator, are linked into chains by intermolecular C=O...H—N hydrogen bonds. These chains are weakly interconnected by π–π stacking interactions to form a three‐dimensional framework. A comparison of the geometric parameters of the title molecule and several related benzimidazoles and pyrrolidones is presented.<!?tpb=22pt> 相似文献
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Construction of a High‐Mannose‐Type Glycan Library by a Renewed Top‐Down Chemo‐Enzymatic Approach
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Dr. Kohki Fujikawa Dr. Akihiko Koizumi Dr. Masakazu Hachisu Dr. Akira Seko Dr. Yoichi Takeda Dr. Yukishige Ito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3224-3233
A comprehensive method for the construction of a high‐mannose‐type glycan library by systematic chemo‐enzymatic trimming of a single Man9‐based precursor was developed. It consists of the chemical synthesis of a non‐natural tridecasaccharide precursor, the orthogonal demasking of the non‐reducing ends, and trimming by glycosidases, which enabled a comprehensive synthesis of high‐mannose‐type glycans in their mono‐ or non‐glucosylated forms. It employed glucose, isopropylidene, and N‐acetylglucosamine groups for blocking the A‐, B‐, and C‐arms, respectively. After systematic trimming of the precursor, thirty‐seven high‐mannose‐type glycans were obtained. The power of the methodology was demonstrated by the enzymatic activity of human recombinant N‐acetylglucosaminyltransferase‐I toward M7–M3 glycans, clarifying the substrate specificity in the context of high‐mannose‐type glycans. 相似文献
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《Angewandte Chemie (International ed. in English)》2017,56(20):5531-5535
A porous crystal family has been explored as alternatives of Nafion films exhibiting super‐proton conductivities of ≥10−2 S cm−1. Here, the proton‐conduction natures of a solution‐processed film of nanoparticles (NPs) have been studied and compared to those of a Nafion film. A mono‐particle film of Prussian‐blue NPs is spontaneously formed on a self‐assembled monolayer substrate by a one‐step solution process. A low‐temperature heating process of the densely packed, pinhole‐free mono‐particle NP film enables a maximum 105‐fold enhancement of proton conductivity, reaching ca. 10−1 S cm−1. The apparent highest conductivity, compared to previously reported data of the porous crystal family, remains constant against humidity changes by an improved water‐retention ability of the film. In our proposed mechanism, the high‐performing solution‐processed NP film suggests that heating leads to the self‐restoration of hydrogen‐bonding networks throughout their innumerable grain boundaries. 相似文献
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Dr. Dmitry S. Turygin Dr. Michael Subat Prof. Vladimir V. Arslanov Prof. Burkhard König Prof. Maria A. Kalinina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(34):10560-10568
The hydrogen‐bond‐guided self‐assembly of 5′‐ribonucleotides bearing adenine(A), cytosine (C), uracil (U), or guanine (G) bases from aqueous solution on a lipid‐like surface decorated with synthetic bis(ZnII–cyclen) (cyclen=1,4,7,10‐tetraazacyclodododecane) metal–complex receptor sites is described. The process was studied by using surface plasmon resonance spectroscopy. The data show that the mechanism of nucleotide binding to the 2D template is influenced by the chemistry of the bases and the pH value of the solution. In a neutral solution of pH 7.5, the process is cooperative and selective with respect to Watson–Crick pairs (A–U and C–G), which form stable double planes in accordance with the Chargaff rule. In a more acidic solution at pH 6.0, the interactions between complementary partners become non‐cooperative and the surface also stabilizes mismatched and wobble pairs due to the pH‐induced changes in the receptor coordination state. The results suggest that hydrogen bonding plays a key role in the self‐assembly of complementary nucleotides at the lipid‐like interface, and the cooperative character of the process stems from the ideal matching of the orientation and chemistry of all the interacting components with respect to each other in neutral solution. 相似文献