• Title/Summary/Keyword: Direct Synthesis

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Direct Synthesis of ${\eta}^6$-1-Functionally Substituted 2,3,4,5-Tetraphenyl-1-Silacyclopentadiene Complexes of Chromium

  • Wan-Chul Joo;Jang-Hwan Hong;Hong Lae Sohn;Eun-Kyoung Kang;Chang-Hwan Kim
    • Bulletin of the Korean Chemical Society
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    • v.11 no.1
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    • pp.31-33
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    • 1990
  • We synthesized the novel complexes of (1,1-dimethyl-3,4-diphenyl-1-silacyclopenta-2,4-di ene-2,5-yldibenzene)bis(tricarbonylchromium) and tricarbonyl (R,R'-3,4,5-triphenyl-1-silacyclopenta-2,4-diene-2 -ylbenzene)chromium(R,R' = Me, R = Me/R' = Cl, R = Ph/R' = Cl) from the reaction of the corresponding R,R'-2,3,4,5-Tetraphenyl-1-silacyclopenta-2,4-dien e (abr. R,R'-TPSCp) with chromiumhexacarbonyl. These results reveal that chromium prefer to coordinate to the phenyl substituents of 1-silacyclospentadiene rather than the butadiene moiety of the ring.

Synthesis and Charaterization of Diametrically Substituted p-Diacetylcalix[4]arene

  • Hwang Kyung Lan;Ham Si-Hyun;No Kwanghyun
    • Bulletin of the Korean Chemical Society
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    • v.13 no.6
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    • pp.689-695
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    • 1992
  • Methods for the selective functionalization of calix[4]arene at the upper rim are described. The diametrically substituted calix[4]arene dimethyl ether 2, obtained from the treatment of calix[4]arene 1 with methyl iodide in the presence of $K_2CO_3$, is converted to the two isomeric p-diacetylcalix[4]arene dimethyl ether 3 and 6 by direct substitution and by Fries rearrangement of corresponding diacetyloxycalix[4]arene dimethyl ether 5 respectively. Diametrically substituted p-diacetylcalix[4]arene 8 was also prepared by Fries rearrangement of calix[4]arene tetraacetate 7 using a limited amount of $AlCl_3$.

Synthesis of Polymers Having N-Hydroxymaleimide Units by Thermolysis of N-(Isopropyloxycarbonyloxy)maleimide Polymers

  • An, Gwang Deok;C. Grant Willson
    • Bulletin of the Korean Chemical Society
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    • v.16 no.5
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    • pp.443-449
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    • 1995
  • N-(Isopropyloxycarbonyloxy)maleimide (iPOCMI) has been synthesized and polymerized to give both the homopolymer and copolymers with substituted styrenes. These polymers were readily deprotected by thermolysis of the isopropyloxycarbonyl (iPOC) groups to provide the corresponding N-hydroxymaleimide (HOMI) polymers. The homopolymer and styrenic copolymers of iPOCMI were radically obtained in higher conversion and higher molecular weight than those obtained by direct polymerizations of N-hydroxymaleimide. The homopolymer of iPOCMI was transformed into poly(N-hydroxymaleimide)P(HOMI) by thermolysis of iPOC groups at 205 $^{\circ}C$ with concurrent release of propene and carbon dioxide. The copolymer of iPOCMI and styrene was thermally deprotected to the copolymer of HOMI and styrene at 235 $^{\circ}C.$ The mass loss was 28% and the Tg of the resulting copolymer was 250 $^{\circ}C.$ The thermal deprotection readily provided the desired, polar HOMI polymers which have Tgs above 240 $^{\circ}C.$ The deprotection was accompanied by large changes in aqueous base solubility.

Synthesis of (Z)-, and (E)-8-Dodecen-1-yl Acetate, The Sex Pheromone of the Oriental Fruit Moth, Grapholitha Molesta by Stereochemical Control in Wittig Olefination

  • Kang, Suk-Ku;Kim, Jung-Hawn;Shin, Yaung-Chul
    • Bulletin of the Korean Chemical Society
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    • v.7 no.6
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    • pp.453-457
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    • 1986
  • Stereochemical control of the Wittig reaction of the primary aldehyde, 8-acetoxyoctan-1-al (7) with the nonstabilized alkylide, triphenylphosphonium n-butylide (6), was achieved by controlling the reaction conditions including solvent, temperature and inorganic salts. These conditions can be applied to the direct sythesis of the mixture of (Z)-, and (E)-8-dodecen-1-yl acetate, the sex pheromone of the oriental fruit moth, Grapholitha molesta. The primary aldehyde, 8-acetoxyoctan-1-al (7) was synthesized from 1,8-octanediol which is cheap and readily available.

Synthesis and X-ray Crystallographic Characterization of p-Diacetylcalix[4]arene

  • Young Ja Park;Kwanghyun No;Jung Mi Shin
    • Bulletin of the Korean Chemical Society
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    • v.12 no.5
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    • pp.525-529
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    • 1991
  • A simple route is described for the selective functionalization of calixarene at the para positions of phenyl rings. Calix[4]arene tetraacetate 2, obtained from the treatment of calix[4]arene with acetic anhydride, undergoes Fries rearrangement to yield the diametrically para substituted p-diacetylcalix[4]arene 3 in 80% yield. The crystal and molecular strucutre has been determined by X-ray diffraction method. The crystals are orthorhombic, space group Pna21, with a = 11.121 (3), b = 10.374 (3), c = 21.690 (6) $\AA$ and Z = 4. The structure was solved by direct method and refined by full-matrix least-squares methods to final R of 0.036 for 1795 observed reflections. Each hydroxyl hydrogen atom is disordered over two positions. The macrocycle exists in the cone conformation which is determined by the strong circular intramolecular flip-flop type hydrogen bonds of phenolic OH, while crystal packing effects of the diametrically para-acetyl substituents seem to be responsible for the distortion of the cone conformation.

Synthesis of New Anthracycline Derivatives Including Butyric or Retinoic Acid Moiety.

  • Rho, Young S.;Kim, Wan Jung;Park, Si Ho;Yu, Dong Jin;Gang, Heun Su;Jeong, Sun Ryang
    • Bulletin of the Korean Chemical Society
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    • v.22 no.6
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    • pp.581-586
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    • 2001
  • The potential anticancer agents, new anthracycline analogues (2-9) have been synthesized from the glycosides daunomycin (1a) and doxorubicin (1b). Compounds 2 and 6 were prepared by nucleophilic displacement esterification of a 14-bromodauomycin(1c) with sodium or potassium salts of butyric and all trans retinoic acid, respectively. Compounds 3 and 7 were obtained from daunomycin (1a) by direct amidation with a butyric and all trans retinoic acid in the presence of EDCI and PP, respectively. Compounds 4 and 8 were obtained from doxorubicin (1b) by reaction with the corresponding acids in the same manner. Compounds 5 and 9 were prepared from doxorubicin (1b) by acylation with two equivalents of the corresponding acids under the same reaction conditions.

Synthesis of New Anthracyline Derivatives Containg Acetylsalicyclic or Palmitic Acid Moiety.

  • Rho, Young S.;Kim, Wan Jung;Park, Si Ho;Yu, Dong Jin;Gang, Heun Su;Jeong, Sun Ryang
    • Bulletin of the Korean Chemical Society
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    • v.22 no.6
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    • pp.587-592
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    • 2001
  • The potential anticancer agents new anthracycline derivatives (2~9) have been synthesized from daunomycin (1a) and doxorubicin (1b) ad starting materials. Compounds 2 and 6 were prepared by the nucleophilic displacement type esterification of a 14-bromodaunomycin (1c) with a acetylsalicylic and palmitic acid in triethylamine, respectively. Compound 3 and 7 were obtained from daunomycin (1a) by direct amidation with the corresponding acids in the presence of EDCI and PP as esterification regents. Whereas 4 and 8 were prepared by reaction of doxorubicin (1b) with one equivalent of acetylsalicylic and palmitic acid using DCC/DMAP, respectively, 5 and 9 were obtained from 1b by acylation with two equivalents of the corresponding acids using EDCI/PP reagents.

Formation and Reactions of α-Phosphoryl Thiocarbocations: Synthesis of α-Sulfenyl Phosphonates

  • 김택현;오동영
    • Bulletin of the Korean Chemical Society
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    • v.16 no.7
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    • pp.609-613
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    • 1995
  • The reaction of chloro(methylthio and arylthio)methanephosphonate (1) and Pummerer-type reaction of sulfinylmethanephosphonate (2) with nucleophiles such as aromatic compounds and thiols were examined. The direct chlorination of (methylthio and arylthio)methanephosphonate with N-chlorosuccinimide (NCS) led to the formation of monochlorinated phosphonates (1) in good yield. The reaction of 1 with aromatic compounds and thiols in the presence of stannic chloride afforded a variety of aryl(methylthio)methanephosphonates (3) and thioacetals of formylphosphonates (4), respectively. Phosphonates 3 and 4 were also obtained from the reaction of Pummerer intermediate, generated from sulfinylmethanephosphonate (2), with aromatic compounds and thiols, respectively. A versatile reaction conditions to generate Pummerer intermediate were examined. The best condition was the combination of trifluoroacetic anhydride with stannic chloride. All reactions may involve an initial formation of α-phosphoryl thiocarbocation and a subsequent nucleophilic attack of aromatic compounds and thiols.

Properties, Preparation, and Energy Storage Applications of Two-dimensional Molybdenum Disulfide (2차원 이황화몰리브덴의 성질, 제조 및 에너지 저장 소자 응용)

  • Choi, Bong Gill
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.133-140
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    • 2019
  • Two-dimensional (2D) ultrathin molybdenum dichalcogenides $MoS_2$ has gained a great deal of attention in energy conversion and storage applications because of its unique morphology and property. The 2D $MoS_2$ nanosheets provide a high specific surface area, 2D charge channel, sub-nanometer thickness, and high conductivity, which lead to high electrochemical performances for energy storage devices. In this paper, an overview of properties and synthetic methods of $MoS_2$ nanosheets for applications of supercapacitors and rechargeable batteries is introduced. Different phases triangle prismatic 2H and metallic octahedral 1T structured $MoS_2$ were characterized using various analytical techniques. Preparation methods were focused on top-down and bottom-up approaches, including mechanical exfoliation, chemical intercalation and exfoliation, liquid phase exfoliation by the direct sonication, electrochemical intercalation exfoliation, microwave-assisted exfoliation, mechanical ball-milling, and hydrothermal synthesis. In addition, recent applications of supercapacitors and rechargeable batteries using $MoS_2$ electrode materials are discussed.