Special Issue

Victor Snieckus's Special Issues, Vol. 88, No. 1, 2014

65 data found. 61 - 65 listedFirst Previous
Short Paper | Special issue | Vol 88, No. 1, 2014, pp. 779 - 787
Published online: 7th August, 2013
DOI: 10.3987/COM-13-S(S)45
Mosher's Amide-Based Assignment of the Absolute Configuration of Phantasmidine

Quan Zhou and Barry B. Snider*

*Department of Chemistry MS 015, Brandeis University, 415 South Street, Waltham, MA 02454-9110, U.S.A.

Abstract

The absolute configuration of phantasmidine was assigned by analysis of the two conformers of the two Mosher amides. The expected shielding of the protons adjacent to the nitrogen and large long range shielding (~1 ppm) of the cyclobutane methylene protons in 16major and the pyridine protons of 16minor by the phenyl group of the Mosher amide allows the assignment of absolute configuration as shown in Schemes 4 and 5.

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Short Paper | Special issue | Vol 88, No. 1, 2014, pp. 789 - 797
Published online: 26th July, 2013
DOI: 10.3987/COM-13-S(S)48
Diversity Oriented Approach to Spirobarbituric Acid Derivatives via a [2+2+2] Cycloaddition and Diels‒Alder Reaction as Key Steps

Sambasivarao Kotha* and Rashid Ali

*Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, India

Abstract

Spirobarbituric acid derivatives are assembled via a [2+2+2] cycloaddition and the Diels-Alder (DA) reaction as key steps. A transient diene 13 containing spiribarbituric acid suitable for DA reaction has been generated in situ from the sultine derivative 12, which in turn was obtained by the usage of rongalite.

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Short Paper | Special issue | Vol 88, No. 1, 2014, pp. 799 - 806
Published online: 23rd July, 2013
DOI: 10.3987/COM-13-S(S)57
A Facile and Convenient Synthetic Method for Fluorine-Containing Dibenzo[b,h][1,6]naphthyridines, Thiochromeno[3,2-c]quinolines, and Chromeno[3,2-c]quinolines

Etsuji Okada,* Mizuki Hatakenaka, Masayuki Kuratani, Takashi Mori, and Takuro Ashida

*Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

Novel fluorine-containing dibenzo[b,h][1,6]naphthyridines (3), thiochromeno[3,2-c]quinolines (5), and chromeno[3,2-c]quinolines (7) were synthesized in moderate to high yields by the trifluoromethanesulfonic acid catalyzed cyclization of N-aryl-3-trifluoroacetyl-4-quinolylamines (2) and aryl 3-trifluoroacetyl-4-quinolyl sulfides (4) and ethers (6), easily prepared by aromatic nucleophilic substitution reactions of N,N-dimethyl-3-trifluoroacetyl-4-quinolylamine (1) with p-substituted anilines, thiophenols, and phenols, respectively.

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Short Paper | Special issue | Vol 88, No. 1, 2014, pp. 807 - 815
Published online: 1st August, 2013
DOI: 10.3987/COM-13-S(S)62
Rapid and Convergent Assembly of Natural Benzo[c]phenanthridines by Palladium/Norbornene Catalysis

Pierre-Alexandre Deyris, Tatiana Caneque-Cobo, Filipe Gomes, Vanessa Narbonne, Giovanni Maestri,* and Max Malacria*

*ICNS-CNRS UPR2301, Institut Parisien De Chimie Moléculaire (IPCM), Université Pierre et Marie Curie (UPMC), 4 place Jussieu, 75252 Paris Cedex 05 Bâtiment F/74, France

Abstract

A straightforward total synthesis of a small panel of natural benzo[c]phenanthridines is described. The selective coupling of an aryl triflate with a bromobenzylamine by means of palladium/norbornene joint catalysis and a sequential transfer hydrogenation deliver these alkaloids in one pot. Dihydrophenanthridines initially formed undergo dehydrogenation smoothly while norbornene acts both as a catalyst for their assembly and as a sacrificial olefin in their dehydrogenation.

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Short Paper | Special issue | Vol 88, No. 1, 2014, pp. 817 - 825
Published online: 1st August, 2013
DOI: 10.3987/COM-13-S(S)66
Selective Synthesis of Benzyl Enol Ethers of β-Dicarbonyl Compounds in Basic Condition and the Application towards Synthesis of Naphthoquinones

Kazuaki Katakawa, Dai Yonenaga, Tomoyo Terada, Naoya Aida, Airi Sakamoto, Keishi Hoshino, and Takuya Kumamoto*

*Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi Nishitokyo Tokyo, Japan

Abstract

Selective synthesis of benzyl enol ether of β-tetronic acids and β-dicarbonyl compounds in basic condition was examined. Benzylation of α-methyl-β-tetronic acid with benzyl tosylate in the presence of potassium carbonate gave the corresponding benzyl enol ether exclusively. The reaction of β-tetronic acid and cyclic 1,3-diketones gave the O-benzyl adducts preferentially than the C,O-dibenzylated ones. Diels-Alder reaction of furan derived the benzyl enol ether of α-methyl-β-tetronic acid and benzyne furnished the functionalized napthoquinone derivatives.

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