HETEROCYCLES

■ Contents

■ The Synthesis of Heterocyclic Compounds Based on 3-Formylchromone via Organic Reactions

Ghodsi Mohammadi Ziarani,* Parisa Mofatehnia, Fatemeh Mohajer, and Razieh Moradi

*Department of Chemistry, Alzahra University, Vanak Square, Tehran, P.O. Box 1993891176, Iran

Abstract

3-Formylchromones are known as key heterocyclic scaffolds for the synthesis of various important organic compounds. The compounds with 3-formylchromone have attracted much attention among heterocyclic structures. This review article aims to provide an overview of multi-component reactions related to 3-formylchromone derivatives in the synthesis of various heterocyclic compounds covering the literature going back to 2015 until 2019.

■ HBTU-Catalyzed Simple and Mild Protocol for the Synthesis of Quinoxaline Derivatives

Bhushan B. Popatkar* and Gangadhar A. Meshram

*Department of Chemistry, University of Mumbai, Vidyanagari, Kalina, Santacruz (E), Mumbai, India

Abstract

HBTU-catalyzed, simple, mild, and effective protocol for the synthesis of quinoxalines has been established. The reaction between 1,2-diamines, benzil, and catalytic amount of HBTU in ethanol resulted into quinoxalines. Various aliphatic, aromatic and heterocyclic 1,2-diamines reacted smoothly with benzil to obtained the title compounds in moderate to high overall yield. Use of environmentally benign solvent, high yield of the product, comparably less reaction time and mild reaction condition are advantages of this method.

■ Synthesis and Characterization of Pd(II) and Ru(II) Complexes of Tetradentate N,N,N,N-(Diphosphinomethyl)amine Ligands: Catalytic Properties in Transfer Hydrogenation and Heck Coupling Reactions

Serhan Uruş,* Mustafa Keleş, and Seda Köşker Akkaya

*Chemistry Department, Faculty of Science and Letters, Kahramanmaras¸ Sütçü İmam University, 46100, Kahramanmaraş¸ Turkey

Abstract

Tetradentate N,N,N,N-(diphosphinomethyl)amine ligands and their Pd(II) and Ru(II) complexes were synthesized under a nitrogen atmosphere using Schlenk technique. The synthesized ligands and the complexes were characterized with 1H- and 31P-NMR, FT-IR, TG/DTA, and elemental analysis techniques. Pd(II) Complexes were used as catalysts in Heck coupling reactions and Ru(II) complexes were tried in transfer hydrogenation reactions of acetophenone derivatives. According to the results, L4-Pd(II) complex showed the best catalytic activity in the Heck coupling reaction of p-methylbromobenzene with o-chlorostyrene. It was confirmed that the reduction of bromo and chloroacetophenones in all catalysts the conversions were higher. The results showed that Ru(II) complexes as efficient catalysts and up to 99% conversions was occurred with bromo and chloro acetophenones in K2CO3/isopropyl alcohol media at 80 °C.

■ Synthesis, Characterization and Antimicrobial Evaluation of Some Novel Chromenopyridine, Pyranochromene and 3-Hetarylcoumarin Derivatives

Khaled S. Mohamed* and Engy E. Elbialy

*Engineering Chemistry Department, Higher Institute for Engineering and Technology, New Damietta, New Damietta 34518, Egypt

Abstract

3-Acetylcoumarin was used as a precursor for the synthesis of novel fused heterocyclic compounds as chromeno[3,4-c]pyridine, chromeno[4,3-b]pyridine and pyrano[3,4-c]chromene derivatives in addition to the synthesis of 3-hetarylchromene derivatives. The chemical structures of newly synthesized compounds were avowed by means of spectral and analysis data. The novel synthesized compounds were estimated as antibacterial agents against Staphylococcus aureus and Escherichia coli bacteria.

■ Reactivity of 6-Ethyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxaldehyde towards Some Nucleophilic Reagents

Magdy A. Ibrahim,* Mohamed Abass, Hany M. Hassanin, and Al-Shimaa Badran

*Department of Chemistry, Faculty of Education, Ain Shams University, Roxy 11757, Cairo, Egypt

Abstract

6-Ethyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbox-aldehyde (1) was prepared and utilized as a starting material. Carboxaldehyde 1 was subjected to react with a diversity of carbon nucleophiles producing a variety of condensation products as well as heterocyclic rings linked pyrano[3,2-c]quinolines. Also, reaction of carboxaldehyde 1 with p-toluidine, heterocyclic amines and some hydrazine derivatives produced a variety of products. The structures of the new synthesized products were deduced on the basis of their analytical and spectral data.

■ Recyclable Triphenylbismuth(V) Bisperfluorooctanesulfonate Catalyzed Synthesis of Dihydropyrimidinones

Ablimit Abdukader,* Rong Wang,* and Marhaba Mamat

*School of Chemistry and Chemical Engineering, Xinjiang University, Shengli Road 666,Urumqi,China, 8300046, China

Abstract

Triphenylbismuth(V) bisperfluorooctanesulfonate Ph3Bi(OSO2C8F17)2 was successfully synthesized by treatment of Ph3BiCl2 with C8Fl7SO2OAg, and was found to have the nature of air-stability, water tolerance, high thermal stability and strong Lewis acidity. This complex showed high catalytic efficiency for the synthesis of dihydropyrimidinones (DHPMs) via three-component reaction of aromatic aldehydes, 1,3-dicarbonyl compound and urea under mild conditions. Furthermore, it can be reused without loss of activity in a test of five cycles. Hence, here we provide a convenient and efficient method for preparation of dihydropyrimidinones.

■ Synthesis of Lesinurad via a Multicomponent Reaction with Isocyanides and Disulfides

Yaoqi Li and Zhihua Sun*

*College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, 333 Longteng Rd., Songjiang, Shanghai, 201620, China

Abstract

An efficient synthesis of Lesinurad, a selective uric acid reabsorption (URAT1) inhibitor, is described in this article. The route to synthesis of Lesinurad avoids the use of thiophosgene and the formation of thiols. The key reaction in this synthesis is construction of the 1,2,4-triazole ring in 72% yield. The title product is obtained in 45% yield over 5 steps.

■ Insertion Reaction of Chalcogens into an Al–P Bond

Tatsuya Yanagisawa, Yoshiyuki Mizuhata,* and Norihiro Tokitoh*

*Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan

Abstract

We examined the reactions of a phosphanylalumane (>Al–P<) with chalcogen sources as a part of our investigation of the reactivity of the Al–P bonds. In the case of sulfur source, two S atoms were inserted into the Al–P bond to afford an [Al–S–P–S] heterocycle. Structural analysis and theoretical calculations revealed a charge-separated structure between the [Al]+ and [S2P]– moieties of the [Al–S–P–S] 4-membered ring, which is different from the [B–S–P–S] ring having concrete B–S σ-bonds in the 4-membered ring.