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13 data found. 1 - 13 listed

Published online: 8th February, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14025
Site-Selective Acylation of Carbohydrates Directed by Recyclable Polymer-Supported Isothiourea Catalysts

Wang-Ze Song,* Kun Dong, Ming Li, Jun-Hao Li, Karim Ullah, and Yu-Bin Zheng

*School of Pharmaceutical Science and Technology, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province 116024, China

Abstract

The polystyrene-supported isothiourea catalysts, derived from the homogeneous catalyst BTMs, were synthesized and applied to the site-selective acylation of carbohydrates. The catalysts can be recovered and reused conveniently for 10 cycles without significantly loss in either activity or selectivity. It offers a sustainable and environmentally benign approach for the site-selective functionalization of carbohydrates.

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Published online: 7th February, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14024
Synthesis, Crystal Structure, Spectroscopic and Computational Studies of 2-{1-[2-(1,3-Dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazono]ethyl}pyridine

Ahmad S. Abushamleh,* Kayed A. Abu-Safieh,* Monther A. Khanfar, Khaleel I. Assaf, Bader A. Salameh, and Nisreen J. Alwahsh

*Department of Chemistry, Faculty of Science, Hashemite University, P.O. Box 330127 Zarqa, 13133, Jordan

Abstract

2-{1-[2-(1,3-Dimethyl-4-nitro-1H-pyrazol-5-yl)hydrazono]ethyl}- pyridine has been prepared from 5-hydrazino-1,3-dimethyl-4-nitro-1H-pyrazole and 2-acetylpyridine in an ethanolic solution. It crystallizes as an (E/Z) isomeric pair in the triclinic space group P-1 with the lattice parameters: a = 10.357(1) Å, b = 11.613(1) Å, c = 13.069(1) Å, α = 67.74(1)°, β = 70.77(1)°, γ = 67.92(1)°, volume = 1315.6(3) Å3, Z = 2. The isomeric pair (E/Z) is contained in the unit cell, where the N-H group is H-bonded to the pyridine nitrogen and to the oxygen of the nitro group in the Z-isomer and to the oxygen of the nitro group only in the E-isomer. NMR showed that the E-isomer is the major. DFT calculations were performed to further investigate the electronic properties of the synthesized compound.

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Published online: 1st February, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14015
Bis-Heterocycles. Part II. Tetrahydro-3,3'-bi(1,2,4,5-oxatriazines)

Mustafa M. El-Abadelah, Firas F. Awwadi, Monther S. Zreid, and Mohammed M. Abadleh*

*Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, University of Petra, Amman 11196, Jordan

Abstract

A new set of tetrahydro-3,3'-bi(1,2,4,5-oxatriazines) 3a-e has been prepared via condensation reaction of alkanone- and cycloalkanone N-methylhydrazones with bis-nitrile oxide. Structures of the synthesized bis-heterocycles are based on IR, NMR and MS spectral data and further confirmed by single-crystal X-ray diffraction analysis for compounds 3a and 3d. Compound 3c exhibited inhibitory activity against butyrylcholinesterase (BChE) with IC50 = 1.75 × 10-5 μM.

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Published online: 31st January, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-S(F)81
Ring-Opening Metathesis of N-Alkenyl β-Lactams

Sambasivarao Kotha,* Sunil Pulletikurti, and Yuvaraj Dommaraju

*Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India

Abstract

We have synthesized a new class of N-alkenylated β-lactam derivatives and studied their metathetic behavior. Here, ring-opening metathesis is more favorable than ring-rearrangement metathesis. Molecular modelling studies revealed that the orientation of two olefinic moieties of β-lactam derivatives are far apart and therefore ring-rearrangement metathesis did not occur and ring-opening metathesis is only feasible.

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Published online: 29th January, 2019

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-898
Divergent Synthesis of Steroid Analogs from Steroidal β-Formylenamides, Conjugated Enones and β-Formylvinyl Halides

Geetmani S. Nongthombam and Romesh C. Boruah*

*Chemical Science and Technology Division, CSIR-North East Institute of Science & Technology, Jorhat, Assam, India 785006

Abstract

In the past two decades, our laboratory has been actively engaged in the design and synthesis of novel heterosteroidal analogues. Three functional groups namely β-formylenamide, conjugated enone and β-formylvinyl halide were primarily employed in various reactions to afford a library of novel heterosteroids. The synthetic strategies have been concomitantly utilized in the relevant non-steroidal β-formylenamides, conjugated enones and β-formylvinyl halides.

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Published online: 24th January, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14006
Reaction of 2,3,5,6,7,8-Hexahydroquinoxaline with Thiourea Derivatives: Analysis of the Structure and Conformational State of [4.4.3]Propellane

Kazuhide Nakahara,* Koki Yamaguchi, and Hisao Kansui

*Department of Integrative Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan

Abstract

The reaction of 2,3,5,6,7,8-hexahydroquinoxaline with thiourea derivatives yields a propellane-type tetraazaindene structure, whose conformation was established by 2D NMR analysis and molecular orbital calculations, and verified by single-crystal X-ray diffraction analysis. Further, the result obtained from X-ray analysis of this propellane-type tetraazaindene structure indicated that the crystalline state was stabilized by specific hydrogen bonds; four hydrogen bonds were of the type >C=S•••H–N, four of N–H•••N type between the imidazolidine moieties, and two of >C=S•••H–C type.

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Published online: 22nd January, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14016
Efficient Synthesis of Chiral 5-Methoxycarbonyl Pyridin-2(1H)-Ones and 3-Bromo-5-methoxycarbonyl Pyridin-2(1H)-ones

Hugo Pilotzi, Dino Gnecco,* María L. Orea,* David M. Aparicio, Sylvain Bernes, Jorge R. Juárez, and Joel L. Terán

*Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Edif. IC9 Complejo de Ciencias, C.U., 72570 Puebla, Mexico

Abstract

Starting from the mixture methyl-(S)-3-(1-phenylethylamino)acrylate 1-(E,Z) and the mixture methyl (R)-3-(2-(tert-butyldimethylsilyl)oxy-1-phenylethyl)amino acrylate 2-(E,Z) were synthesized the corresponding chiral 5-carbomethoxy-pyridin-2(1H)-ones in high yield. Finally, starting from these chiral pyridin-2(1H)-ones were prepared the corresponding 3-bromo-5-carbomethoxy-pyridin-2(1H)-ones in high yield.

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Published online: 22nd January, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14020
4,6-Diacetylresorcinol in Heterocyclic Synthesis Part II: Synthesis of Some Novel 4,6-Bis(azolyl/azinyl/azepinyl)resorcinols

Mohammed A. Assiri, Tarik E. Ali,* Magdy A. Ibrahim, E. M. El-Amin, and I. S. Yahia

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

Abstract

A series of new 4,6-bis(azolyl/azinyl/azepinyl)resorcinols was synthesized in a combinatorial manner besides, (2E,2'E)-4,6-bis[3-(aminophenyl-substituted)prop-2-en-1-oxo-1-yl]resorcinols were also obtained. Heterocyclization of (2E,2'E)-4,6-bis[3-(dimethylamino)prop-2-en-1-oxo-1-yl]resorcinol (2) with nitrogen-containing binucleophiles afforded the target compounds. All the newly synthesized compounds were characterized by spectral tools.

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Published online: 21st January, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14010
Divergent Synthesis of 5,6- and 3,6-Dihydropyridin-2(1H)-one via Intramolecular Knoevenagel Condensation

Arturo Bocardo-Bautista, María L. Orea, Jorge R. Juárez, Dino Gnecco, David M. Aparicio,* and Joel L. Terán*

*Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Edif. IC9, Complejo de Ciencias, C.U. 72570 Puebla, Pue., México.

Abstract

A simple and friendly strategy for the regioselective synthesis of 5,6- and 3,6-dihydropyridin-2(1H)-one via intramolecular Knoevenagel condensation from a common methyl 3-((2-(1,3-dioxolan-2-yl)ethyl)alkylamino)-3-oxopropanoate under acidic conditions is reported.

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Published online: 21st January, 2019

Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14019
Synthesis of 4,4-Dimethyl-2-(2-pyrrolyl)-2-oxazolines

Kentaro Okano,* Kazuki Morii, Daichi Mari, and Atsunori Mori

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

Abstract

A practical synthesis of 4,4-dimethyl-2-oxazolines on pyrrole was achieved via the cyclization of the corresponding amides, which were derived from the trichloroacetylpyrroles. The established conditions were applicable to pyrroles bearing a ketone or an ester moiety. In addition to pyrroles, the method could be extended to the synthesis of the indole derivative.

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Published online: 18th January, 2019

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14021
Synthesis of 2H-Benzo[b]thietes by TFA-Mediated Cyclization of O-tert-Butyl S-(2-Vinylphenyl) Carbonothioates via 4H-3,1-Benzoxathiin-2-one Intermediates

Kazuhiro Kobayashi* and Takuma Ueyama

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

An efficient method for the preparation of 2H-benzo[b]thiete derivatives under mild conditions has been developed. The reaction of 2-(1-arylethenyl)phenyl bromides with butyllithium at –78 ˚C generates 2-(1-arylethenyl)phenyllithiums, which are successively treated with sulfur and Boc2O at the same temperature to afford S-[2-(1-arylethenyl)phenyl] O-tert-butyl carbonothioates. These compounds are then treated with TFA at 0 or 20 ˚C to yield 2-aryl-2-methyl-2H-benzo[b]thietes via formation of the 4-aryl-4-methyl-4H-3,1-benzoxathiin-2-ones followed by decarboxylation.

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Published online: 18th December, 2018

Review | Regular issue | Prepress
DOI: 10.3987/REV-18-895
Recent Advancements in the Synthesis of Half-Esters and Their Applications

Jianjun Shi and Satomi Niwayama*

*Division of Sustainable and Environmental Engineering, Graduate School of Engineering, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran, Hokkaido, 050-8585, Japan

Abstract

Half-esters are important building blocks for the synthesis of pharmaceuticals, polymers and natural products. Therefore, synthetic methodologies for both chiral and racemic half-esters have been actively investigated for decades. This short review summarizes recent progress in the synthesis of half-esters and their applications including the studies from our laboratories.

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Published online: 18th December, 2018

Short Paper | Regular issue | Prepress
DOI: 10.3987/COM-18-14012
Synthesis of [1,4]Dithiino[2,3-d]pyrimidine-6-carbonitrile Derivatives via the Reaction of 2-[(4-Chloropyrimidin-5-yl)sulfanyl]acetonitriles with Carbon Disulfide

Kazuhiro Kobayashi,* Kota Yamasaki, Daiki Fujiwara, Kazuma Nozaki, Hidetaka Hiyoshi, and Kazuto Umezu

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

An efficient procedure has been developed for the preparation of 7-(alkylsulfanyl)[1,4]dithiino[2,3-d]pyrimidine-6-carbonitrile derivatives from 4,6-dichloro-2-(methylsulfanyl)pyrimidine (DCSMP). 2-{[4-Chloro-2-(methylsulfanyl)pyrimidin-5-yl]sulfanyl}acetonitriles are prepared via the reaction of the 5-lithio derivative of DCSMP with sulfur and then 2-bromoacetonitrile. These can be converted into the desired products on treatment with carbon disulfide in the presence of sodium hydride followed by alkyl halides. This is the first construction of the [1,4]dithiino[2,3-d]pyrimidine structure.

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13 data found. 1 - 13 listed