HETEROCYCLES

■ Contents

■ Synthesis, Biological Activities, and Tautomerism of 4-Quinolones and Related Compounds

Yoshihisa Kurasawa* and Kenji Sasaki

*Department of Organic Chemistry, School of Pharmacy, Iwaki Meisei University, 5-5-1 Chuodai Iino, Iwaki City, Fukushima 970-8551, Japan

Abstract

This review describes the synthesis, biological activities, and tautomerism of various 4-quinolones together with related compounds including 4-oxopyridazino[3,4-b]quinoxalines (bioisostere of 4-quinolones).

■ One-Pot Synthesis of [1,2,3]Triazolo[1,5-a]pyrazine Derivatives from Ynones and Amino Azide

Shinichi Koguchi,* Azusa Sakurai, and Kosuke Niwa

*Faculty of Science, Tokai University, Kitakaname 4-1-1, Hiratsuka, Kanagawa, 259-1292, Japan

Abstract

A new procedure is described for the synthesis of [1,2,3]triazolo[1,5-a]pyrazine derivatives via a one-pot cycloaddition.

■ Cyclohexane-Fused Pyridine Derivatives with Photophysical Properties: Synthesis by “Three-Component” Domino Reaction and Structural Optimization by DFT Calculations

Jianqiang Wang, Ziping Li, Xinzhi Wang, Yixin Zhou, and Cheng Guo*

*College of Science, Nanjing Tech University, Nanjing 211816, China

Abstract

An environment-friendly and highly efficient method for the preparation of 2-amino-4-phenyl-3-cyano-5,6-dihydrobenzo[h]quinoline derivatives was successfully developed via arylaldehyde, 3,4-dihydro-1(2H)- naphthalenone, malononitrile, ammonium acetate in ethanol by “three-component” domino reaction under microwave irradiation. The reaction conditions were optimized by changing microwave power, temperature and time. Their structures were characterized by ESI-MS, 1H-NMR, 13C-NMR, and IR. Their photophysical properties were detected by UV-Vis and fluorescent spectra. The results of density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were applied to simulate spectra of the compounds, which show excellent agreement with observed spectra and provide reasonable explanation on the structures, the molecular frontier orbital, and the electronic absorption spectra.

■ Reaction of 2-Chloro-1-alkyl-1H-Indol-3-carbaldehydes with Barbituric Acids and 5-Methyl-2-phenyl-2,4-dihydropyrazol-3-one. Formation of Compound with Extremely Short Intramolecular Hydrogen Bond in Eight-Membered Pseudocycle

Konstantin F. Suzdalev,* Maria N. Babakova, Victor G. Kartsev, and Konstantin A. Krasnov

*Department of Chemistry, Southern Federal University, Zorge Street 7, Rostov-on-Don, 344090, Russia

Abstract

New indolin-2-one derivatives, containing in its molecules eight-membered pseudo-cycle with unusually short intramolecular hydrogen bond in OHO-bridge have been synthesized by reaction of 2-chloro-1-alkyl-1H-indole-3-carbaldehyde with barbituric acids or 5-methyl-2-phenyl-2,4-dihydropyrazol-3-one. Under the action of amines they undergo fragmentation to 5-aminomethylenebarbituric acids or 4-aminomethylenepyrazolones and 1-alkyl-1,3-dihydroindol-2-ones.

■ Stereoselective Synthesis of the A-Ring of Armatol A from a Bromo-substituted Chiral Building Block Based on Ireland-Claisen Rearrangement and Ring-Closing Olefin Metathesis

Yuta Hirose, Kenshu Fujiwara,* Takafumi Saito, Ryo Katoono, and Takanori Suzuki

*Division of Chemistry, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan

Abstract

The stereoselective synthesis of the A-ring of armatol A, a natural polycyclic ether triterpene from the red alga Chondria armata, was achieved in a non-biomimetic way. The synthesis employed Ireland-Claisen rearrangement of an ester, prepared from a bromo-substituted chiral building block, for the construction of C6 and C7 stereocenters and a relay ring-closing olefin metathesis for the seven-membered ring formation.

■ Ga(OTf)3 Catalyzed Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

Jingjing Xia* and Kehua Zhang

*Materials and chemical engineering, Anhui Jianzhu University, Anhui Jianzhu University 230601, China

Abstract

Gallium(III) triflate was used to catalyze Biginelli-like reactions under solvent-free condition to obtain dihydropyrimidione derivatives in good to excellent yields and short reaction time.

■ One-Pot, Three Component Synthesis of Thiazol-2(3H)-imines Using Poly(4-vinylpyridine) as an Efficient Reusable Heterogeneous Basic Catalyst

Jafar Abbasi Shiran, Asieh Yahyazadeh,* Manouchehr Mamaghani, Bohari M. Yamin, and Farhad Shirini

*Department of Chemistry, College of Science, University of Guilan, Rasht 41335, Iran

Abstract

Poly(4-vinylpyridine) is reported as a green, efficient and reusable basic catalyst for the synthesis of 3H-thiazoles under one-pot, three component reaction. This simple method produces the products at room temperature in excellent yields (83-97%). Furthermore, this catalyst can be recovered by simple filtration and recycled up to four consecutive runs without any loss of its efficiency.

■ Three-Component Synthesis of New Substituted Bis[2-imino-3-(substituted)-4-phenyl-3H-thiazole] Derivatives and Evaluation of Their Antibacterial Activity

Jafar Abbasi Shiran, Asieh Yahyazadeh,* Bohari M. Yamin, Manouchehr Mamaghani, and Hamzeh Kiyani

*Department of Chemistry, College of Science, University of Guilan, Rasht 41335, Iran

Abstract

Several new derivatives of 2,2'-(4,4'-ethylenebiphenyl)bis[2-imino-3-(substituted)-4-phenyl-3H-thiazole], 2,2'-(4,4'-biphenylsolfone)bis[2-imino-3-(substituted)-4-phenyl-3H-thiazole], 2,2'-(4,4'-methylene¬biphenyl)bis[2-imino-3-(substituted)-4-phenyl-3H-thiazole] and 2,2'-(1,4-phenylene)bis[2-imino-3-(substituted)-4-phenyl-3H-thiazole] derivatives were synthesized by the condensation reaction of various isothiocyanates, diamines, and phenacyl bromide. The one-pot, three-component synthesis of new containing-iminothiazole heterocycles conducted using catalytic amounts of triethylamine. Furthermore, the target compound 8b was further determined by X-ray crystallographic analysis. The antimicrobial activity of the synthesized compounds was evaluated against Salmonella enterica, Micrococcus luteus, Bacillus subtilis and Pseudomonas aeruginosa.

■ Synthesis, Characterization and Biological Activity of Some Novel Coumarin Derivatives Containing Pyridine Moiety

Ahmed A. Fadda,* Khaled S. Mohamed, Hala M. Refat, and Engy E. El-Bialy

*Department of Chemistry, Faculty of Science, University of Mansoura, Mansoura 35516, Egypt

Abstract

The 2-acetyl-3H-benzo[f]chromen-3-one (1) was used as a key intermediate for the synthesis of 3-(1-amino-3-oxo-3H-benzo[f]chromen-2-yl) - but-2-enenitrile derivatives 3a-d via condensation reactions with activated nitrile derivatives in the presence of ammonium acetate. Moreover, the 3a-d underwent interamolecular cyclization to form 3-alkyl-2-amino-4-methyl-5-oxo-5H-benzo [5, 6]chromeno[4,3-b]pyridine 4a-d. Compound 1 reacts with acetophenone and cyclohexanone in the presence of cyanoacetamide to afford the benzo[5,6]chromeno[3,4-c]pyridin-5-one derivatives 5 and 6, respectively. Also, 4-aryl-6-[benzo[h]coumarin-3-yl]-3-cyano-2-pyridone derivatives 8a-d were synthesized by an efficient and convenient method by the one-pot reaction of 1 with aromatic aldehydes 7a-d and malononitrile in the presence of sodium hydroxide under a solvent free condition. This method has the advantages of mild reaction conditions, easy workup and inexpensive reagents. Moreover, 2-(4,6-diphenylpyridin-2-yl)-3H-benzo[f]chromen-3-one (16) was prepared via reaction of α-pyrdinium salt of methyl ketone of 1 with benzalacetophenone in the presence of ammonium acetate. The structures of the new synthesized compounds were confirmed by spectral data and elemental analyses. Newly compounds were tested for in vitro cytotoxicity against heptacelluar carcinoma (HepG2) and breast cancer (MCF-7) in addition to their antibacterial evaluation.

■ Further Investigation of Pyranone Activation

Justin A. Simanis, Christian R. Zwick, Erica L. Woodall, John R. Goodell, and T. Andrew Mitchell*

*Campus Box 4160, Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, U.S.A.

Abstract

As part of our ongoing investigation into the activation parameters of pyranones to the corresponding oxidopyryliums, various means were investigated. Screening of acid mediators revealed limited efficiency, with HCl providing the best result. Additional acid-mediated and microwave-assisted studies provided evidence that oxocarbenium formation is a key mechanistic event thwarting formation of oxidopyrylium intermediates. A µW-assisted exchange process was discovered allowing for the rapid synthesis of potentially useful alkoxypyranones.