نتایج جستجو برای: intramolecular cyclization

تعداد نتایج: 18338  

2017
Peng‐Hua Li Jin‐Ming Yang Yin Wei Min Shi

An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6-exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.

Journal: :European Journal of Organic Chemistry 2022

A new strategy has been proposed for the synthesis of an array imidazo[5,1-c][1,4]oxazine chemotypes by using a planned aza-Michael addition in 3-CR heteroring-forming, post-cyclization transformation followed intramolecular fused-heterocycles formation process.

2017
Eito Yoshioka Hideto Miyabe

The synthesis of 1H-benzo[f ]isoindole derivatives was achieved by the cascade radical cyclization–cyclization reaction of the active methine substrate having an allyl group and phenyl group as different two radical acceptors. This oxidative transformation proceeded by using iron(III) chloride FeCl3 as a mild oxidant via the intramolecular radical addition to the allyl group followed by the sec...

Journal: :Organic letters 2010
Yueh-Lin Loo Anna M Hiszpanski Bumjung Kim Sujun Wei Chien-Yang Chiu Michael L Steigerwald Colin Nuckolls

Fluorinated, contorted hexabenzocoronenes (HBCs) have been synthesized in a facile manner via Suzuki-Miyaura coupling of fluorinated phenyl boronic acids followed by photocyclization and Scholl cyclization. In addition to the molecular conformation observed in previous HBC derivatives, close-contact fluorine-fluorine intramolecular interactions result in a metastable conformation not previously...

Journal: :Organic & biomolecular chemistry 2016
K Shiva Kumar Boyapally Bhaskar Meesa Siddi Ramulu N Praveen Kumar Mohd Ashraf Ashfaq Manojit Pal

TFA alone was found to be remarkably effective for the intramolecular hydroarylation (IMHA) of alkynes when employed as a solvent in the cyclization of 3-alkynyl substituted 2-(indol-3-yl)quinoxalines. This simple and metal free cyclization method afforded a range of indolophenazines as new and potential cytotoxic agents. The use of excess TFA was found to be crucial for the success of this rea...

Journal: :Organic & biomolecular chemistry 2006
Marco Angeli Marco Bandini Andrea Garelli Fabio Piccinelli Simona Tommasi Achille Umani-Ronchi

A practical catalytic approach to the synthesis of 4-substituted 1,2,3,4-tetrahydro-beta-carbolines (THBCs, 1) and 1,2,3,9-tetrahydropyrano[3,4-b]indoles (2) via InBr3-catalyzed intramolecular Friedel-Crafts (F-C) cyclization is described. The use of cross-metathesis reaction represents a direct route to the cyclization precursors and the use of InBr3 (5 mol%) allowed polycyclic indole compound...

Journal: :Chemical communications 2014
Makoto Iwata Kyohei Kanoh Takuya Imaoka Kazuo Nagasawa

Cylindradines A and B, members of the polycyclic pyrrole-imidazole alkaloids (PIAs), are the only congeners bearing a 3-carbamoylpyrrole unit among the PIAs. In this communication, we described a total synthesis of (+)-cylindradine A based on intramolecular Friedel-Crafts type cyclization of pyrrole-aldehyde and oxidative cyclization of tricyclic pyrrolopyrrolidine-guanidine with hypervalent io...

Journal: :Angewandte Chemie 2015
Chenlong Zhu Zhaobo Liu Guanyu Chen Kai Zhang Hanfeng Ding

A concise total synthesis of rac-alsmaphorazine D has been described for the first time. The efficient synthetic strategy features four key transformations: 1) a catalytic intramolecular oxidative cyclization for the δ-lactamindole backbone; 2) an oxidative cyclic aminal formation for the hexahydropyrrolo[2,3-b]pyrrole framework; 3) a transannular radical cyclization for the construction of the...

Journal: :Chemical communications 2011
Ho Yong Lee Junyong Jo Hyunsoo Park Dongwhan Lee

The metal-induced intramolecular cyclization reaction of an azo dye was exploited for the colorimetric detection of mercury ions in water. The molecular probe 3 responds selectively to nM-level Hg(II) ions in neutral aqueous solutions.

Journal: :Organic & biomolecular chemistry 2012
Xiaofeng Yang Yixing Guo Robert M Strongin

A fluorescent chemodosimeter for cysteine detection was developed based on a tandem conjugate addition and intramolecular cyclization reaction. The method exhibited an excellent selectivity for cysteine over other biothiols such as homocysteine and glutathione.

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