نتایج جستجو برای: pyran derivatives

تعداد نتایج: 106108  

2013
Chunxia Chen Minghui Lu Zhihui Liu Junting Wan Zhengchao Tu Tianyu Zhang Ming Yan

A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H37Rv. No obvious antitubercular activities could be observed (MIC > 10 g/mL). The results are in sharp contrast with the previously reported data.

Journal: :Organic & biomolecular chemistry 2014
B V Subba Reddy M Ramana Reddy B Sridhar Kiran Kumar Singarapu

An acetal-initiated Prins bicyclization approach has been developed for the stereoselective synthesis of hexahydrofuro[3,4-c]furan lignans. This also provides a direct way to generate a new series of octahydropyrano[3,4-c]pyran derivatives in a single-step process.

Journal: :European Journal of Organic Chemistry 2023

The Front Cover shows 5-bromo-2-(tetrahydro-2H-pyran-4-yl)pyridine – one of many sp3-enriched pyridine derivatives prepared on a multigram scale by group Ukrainian chemists. background photo Anatolii Varenyk depicts the Kilometre Zero Ukraine Sign (also known as “The Winged Globe”) control point located Independence Square (Maidan Nezalezhnosti) in Kyїv. More information can be found Research A...

Egg shell has been utilized as a natural, green, reusable and eco-friendly reagent for the synthesis of spiro[4H-pyran-oxindole] derivatives by one-pot multicomponent reaction of isatins, 1,3-diketones, and malononitrile/ ethyl cyanoacetate. Good functional group tolerance and broad scope of usable substrates are other prominent features of the present methodology.

Journal: :Dyes and Pigments 2021

Abstract A series of new azo disperse dyes was synthesized by coupling 4-hydroxy-6-methyl-2H-pyran-2-one (triacetic acid lactone, TAL) or its hydrogenated derivative 4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one (dihydro triacetic DHTAL) with diazonium salts derived from aniline, 4-bromoaniline, 4-nitroaniline, 4-methoxyaniline, 2,4-dimethoxyaniline and 2,5-dimethoxyaniline. Spectroscopic data ...

In the present work, we have developed a mild, efficient, and environmentally benign method for the synthesis of tetrahydrobenzo[b]pyran derivatives via a three-component cyclocondensation of aldehydes, malononitrile and dimedone utilizing ammonium chloride as a simple, easily available and cost effective catalyst under microwave irradiation. This method has several attracting features such as ...

2015
Philipp Röse Steffen Emge Jun-ichi Yoshida Gerhard Hilt

The cobalt(I)-catalysed 1,4-hydrovinylation reaction of allyloxytrimethylsilane and allyl alcohol with substituted 1,3-dienes leads to hydroxy-functionalised 1,4-dienes in excellent regio- and diastereoselective fashion. Those 1,4-dienols can be converted into tetrahydrofuran and pyran derivatives under indirect electrochemical conditions generating selenium or iodonium cations. The reactions p...

Journal: :Chemical communications 2012
Utpal Das Chan-Hui Huang Wenwei Lin

An organocatalytic construction of optically enriched substituted pyran derivatives via amine-catalyzed Michael addition and subsequent enolization/cyclisation has been described starting from electronically poor alkenes. Functionalized pyrans were obtained in high enantioselectivities (up to 96%) and good yields (up to 90%) having three contiguous chiral centers.

Journal: :Chemical communications 2013
Xiaofeng Ma Qin Tang Jun Ke Jichao Zhang Cong Wang Haibo Wang Yuxue Li Huawu Shao

An effective and facile method for the synthesis of 2,2-di-substituted perhydrofuro[2,3-b]pyran (and furan) derivatives is described. The cyclization of 1,2-cyclopropanated sugars with olefins in the presence of BiCl3 is highly diastereoselective. 2,2-Di-substituted cyclization products were obtained in good to excellent yields.

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