• Title/Summary/Keyword: N-heterocycles

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Synthesis and $^1$H-nmr of N-Arylated Nitrogen-Containing Aromatic Heterocycles

  • Koh Park, Kwang-Hee;Lee, Jae-Bong;Han, Du-Hee
    • Bulletin of the Korean Chemical Society
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    • v.6 no.3
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    • pp.141-144
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    • 1985
  • N-Arylation reaction of nitrogen-containing heterocycles such as pyridine, nicotinamide and 4,4'-bipyridine was studied. We prepared N-2,4-dinitrophenyl derivatives initially by reacting the above heterocycles with 2,4-dinitrochlorobenzene in ethanol, and then treated the N-2,4-dinitrophenylated heterocycles with various aniline derivatives, $XC_6H_4NH_2$(X = -H, p-$CH_3$, p-$C_2H_5$, p-Cl, p-CN, p-OH, p-$OCH_3$, o-Cl, m-$CH_3$) to yield the corresponding N-arylated compounds in fairly good yields. $H^1$-nmr patterns and peak assignments of the N-arylated products were described.

Introduction of Heterocycles at the 2-Position of Indoline as Ester Bioisosteres

  • Lee, Sung-Kyung;Yi, Kyu-Yang;Yoo, Sung-Eun
    • Bulletin of the Korean Chemical Society
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    • v.25 no.2
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    • pp.207-212
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    • 2004
  • In this study, we attempted to prepare compounds with heterocyclic replacements for metabolically unstable esters of benzopyranyl indole-2-carboxylic esters, which showed good in vitro and in vivo cardioprotective efficacies possibly through the opening of mitochondrial ATP-sensitive potassium channel ($K_{ATP}$). Initially, we tried to construct indolin-2-yl-heterocycles using unprotected indoline-2-carboxylic acid, but the cyclization was proceeded with oxidation of the indoline ring to the indole, which didn't react with benzopyranyl epoxide. Thus we introduced N-Boc group to deplete the electron density of the indoline ring. We successfully prepared various indolin-2-yl-heterocycles by the cyclization of the building blocks including carboxamide, ${\beta}$-hydroxy amide, hydrazide, nitrile starting from N-Boc-indoline-2-carboxylic acid.

Synthesis and Fragmentation Behavior Study of n-alkyl/benzyl Isatin Derivatives Present in Small/Complex Molecules: Precursor for the Preparation of Biological Active Heterocycles

  • Kadi, Adnan A.;Al-Shakliah, Nasser S.;Motiur Rahman, A. F. M.
    • Mass Spectrometry Letters
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    • v.6 no.3
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    • pp.65-70
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    • 2015
  • N-Alkyl/benzyl substituted isatin derivatives are intermediates and synthetic precursors for the preparation of biological active heterocycles. N-alkyl/benzyl isatins have showed various biological activities, such as cytotoxicity, antiviral, caspase inhibition, cannabinoid receptor 2 agonists for the treatment of neuropathic pain, etc. In this study, N-alkyl/benzyl isatin derivatives were synthesized from isatin and alkyl/benzyl halides in presence of K2CO3 in DMF and excellent to quantitative yields (~95%) were obtained. Isatins and benzyl-isatins were condensed with fluorescein hydrazide to form fluorescein hydrazone. All the compounds were subjected to their fragmentation behavior study using LC/MSn. N-Alkyl substituted isatin derivatives fragmented at nitrogen-carbon (N-C) bond, hence gave daughter ion as [RN+H]+. Whereas, N-benzyl substituted isatin derivatives fragmented at carbon-carbon (C-C) bond of alkyl chain which linked with nitrogen molecules, therefore gave N-methyl fragments [RNCH2]+. This study demonstrated that, isatin moiety present in a small/large molecule or in a matrix of reaction mixture with/without N-alkyl/benzyl substituents can be identified by mass spectroscopic fragmentation behavior study.

Facile Access to a Variety of 2,5-Biaryl-1,2,4-triazol-3-ones via Regioselective N-Arylation of Triazolones

  • Park, Ji-Yeon;Chae, Jung-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.31 no.8
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    • pp.2143-2146
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    • 2010
  • A selective synthetic method of the 2,5-biaryltriazolones has been developed via copper-catalyzed N-arylation reaction. Aryltriazolones, which were readily prepared from commercially available compounds, were N-arylated to 2,5-biaryltriazolones with high regioselectivity. This approach allows for access to a variety of 2,5-biaryl-1,2,4-trizol-3-ones in a simple and practical manner.

Synthetic Studies on Fused Nitrogen-heterocycles from N-Amino-N,N '-dihydrodiazinediones (II). Condensation of N-Amino-N,N '-dihydrodiazinediones with ${\alpha},{\beta}$-Unsaturated Carbonyl Compounds

  • Sung Chul Shin;Kyung Ho Kang;Youn Young Lee;Yang Mo Goo
    • Bulletin of the Korean Chemical Society
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    • v.11 no.1
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    • pp.22-25
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    • 1990
  • The condensation of 1-amino-1,2-dihydro-3,6-pyridazinedione (1) and 2-amino-2,3-dihydro-1,4-phthalazinedione (2) with mesityl oxide or 3-penten-2-one in acetic acid-ethanol (1:1) gave 3,4,6,9-tetrahydro-6,9-dioxopyridazino[1,2-a][1,2, 3]triazines (9,11) and 3,4,6,11-tetrahydro-6,11-dioxo[1,2,3]triazino[1,2- b]phthalazines (10,12), respectively. The condensation of 1 and 2 with crotonaldehyde, cinnamaldehyde or acrylaldehyde under the same reaction condition gave only N-alkylidene derivatlives (3-8). When the N-alkylidene derivatives isolated from the reaction of 1 and 2 with crotonaldehyde and cinnamaldehyde (3-6) were refluxed in acetic acid, the corresponding heterocyclic compounds (13-16) were obtained.