Selenium Dioxide Oxidations in the b-Carboline Area

Cook, James M.; Campos, Olivia; Cain, M.; Mantei, Robert A.; Gawish, Ali

doi:10.3987/r-1980-07-0975

Cited by 27 publications

(4 citation statements)

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“…Synthesis of pyrido[3,4-b]indoles, the β-carbolines (Scheme ), was examined to further evaluate the general utility of silica gel-supported cerium(III) chloride heptahydrate and sodium iodide. While β-carbolines can be synthesized via tryptamines (vide supra), 4-substituted β-carbolines lacking substitution at the 3-position are not well represented in the literature. We have been especially interested in demonstrating the value of our present procedure by synthesis of methyl 9 H -β-carbolines-4-carboxylate ( 6 ).…”

Section: Resultsmentioning

confidence: 99%

Efficient Preparation of 2-Indolyl-1-nitroalkane Derivatives Employing Nitroalkenes as Versatile Michael Acceptors: New Practical Linear Approach to Alkyl 9H-β-Carboline-4-carboxylate

et al. 2005

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The combination of cerium(III) chloride heptahydrate and sodium iodide supported on silica gel is known to promote Michael-type additions. Continuing our work on solvent-free conditions, the CeCl3.7H2O-NaI-SiO2 system catalyzes the addition of a variety of indoles and nitroalkenes, giving 2-indolyl-1-nitroalkane derivatives in good yields. Development of this method has resulted in a new protocol for the synthesis of 4-substituted beta-carbolines.

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Section: Resultsmentioning

confidence: 99%

Efficient Preparation of 2-Indolyl-1-nitroalkane Derivatives Employing Nitroalkenes as Versatile Michael Acceptors: New Practical Linear Approach to Alkyl 9H-β-Carboline-4-carboxylate

et al. 2005

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“…Recently, water-based and solvent-free adhesives and coatings have progressively become impor-tant in view of recent environmental protection. [1][2][3][4][5][6] In particular, solvent-free adhesives are very useful because curing shrinkage, which is a representative inadequacy of typical solventbased adhesives, hardly occurs and so-called volatile organic compounds can be avoided in this system. [7][8][9] One-component-type adhesives are also central to developments due to their easy handling ability and their balanced performance because mixing is not necessary before the application, and they are now appreciated in the market.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of novel moisture‐curable polyurethanes end‐capped with trialkoxysilane and their application to one‐component adhesives

Nomura

Sato²,

Sato³

et al. 2007

J. Polym. Sci. A Polym. Chem.

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Novel silane endcappers and novel polyurethanes end-capped with trimethoxysilane (silylated polyurethanes) were developed as water-curable materials in which the curing reaction occurred under humid conditions in the presence of dioctyltin diversatate as a curing catalyst. A variety of amine-terminated trimethoxysilane compounds were synthesized by the Michael addition reaction of commercially available 3-aminopropyltrimethoxysilane with acrylates, and the resulting silane endcappers were used to react with isocyanate-terminated polyurethanes, providing the silylated polyurethanes. The moisture-curable silylated polyurethanes were used for the preparation of novel one-component and solvent-free adhesives. The evaluated properties were the curing speed, the tensile shear bond strength, and the adherence to some substrates. The longer alkyl chains of the silane endcappers derived from various acrylates led to a slower curing speed, lower tensile strength at break, and longer elongation at break of the silylated polyurethanes. The tensile shear bond strength of the silylated polyurethane-based adhesive decreased with decreasing the trimethoxysilane end-capping ratio, whereas an increase in the adherence was observed. The adherence to the acrylic substrate was improved by changes in the main-chain structure of the polyurethane based on the composition of poly(propylene oxide) and poly(ethylene oxide).

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“…Syntheses typically involve introduction of the latent 4-substituent in the first synthetic step, Michael addition of indole to a β-substituted nitroolefin. Reduction to a tryptamine, ring closure (either Pictet−Spengler or Bischler-Napieralski), and aromatization have generally been used to complete the synthesis. For the purposes of rapid SAR (structure activity relationship) development, however, this linear approach was impractical, and we required instead a common advanced intermediate suitable for facile derivitization to generate a diverse group of 4-substituted β-carbolines.…”

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confidence: 99%

“…By simply stirring the reaction mixture at ambient temperature in an open flask, air oxidation to 10 was realized in 84% isolated yield. The need for a separate oxidation step, typically performed with sulfur or palladium at high temperature, 1d, was thus conveniently eliminated. The reasons for this facile oxidation of 9 (vs 4 ) were not investigated, yet the 9-SEM group might act to stabilize the presumed benzylic radical, thereby facilitating oxidation with ambient oxygen.…”

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confidence: 99%