Tin-catalyzed Synthesis of Heterocycles Using Isocyanates
T1 - Synthesis of diverse nitrogen-enriched heterocyclic scaffolds using a suite of tunable one-pot multicomponent reactions
to a new series of nitrogen-containing heterocycles are ..
The cyanamide moiety provides many opportunities as a building block for the synthesis of nitrogen-containing heterocycles. This review discusses the reported methods for the preparation of alkyl- and -acylcyanamides and illustrates their reactivity vis-à-vis nucleophilic additions, cycloadditions, radical chemistry and coordination chemistry.
N2 - Five elegant and switchable three-component reactions which enable access to a new series of nitrogen-containing heterocycles are reported. A novel one-step addition of an isocyanide to a hydrazine derived Schiff base affords unique six-membered pyridotriazine scaffolds (A and E). With slight modification of reaction conditions and replacement of the nucleophilic isocyanide moiety with different electrophiles (i.e., isocyanates, isothiocyanates, cyclic anhydrides, and acyl chlorides) five-membered triazolopyridine scaffolds (B, D, F, G) are generated in a single step. Furthermore, the use of phenyl hydrazine enables access to dihydroindazole-carboxamides, devoid of a bridge-head nitrogen (C). All protocols are robust and tolerate a diverse collection of reactants, and as such, it is expected that the new scaffolds and associated chemistry will garner high interest from medicinal chemists involved in either file enhancement or specific target-related drug discovery campaigns.
Asymmetric Synthesis of Nitrogen Heterocycles - …
I am an organic chemist with research interests that cover a wide range of aspects of synthesis. Recent studies have focused on asymmetric synthesis of structurally complex amino acids, using what has proved to be a very versatile radical-based methodology and also the use of structurally unusual heterocycles for masking the reactivity of synthetically valuable functional groups. In this area, we have developed a methodology for the incorporation of protected isocyanates into organic molecules and this chemistry is being applied to the synthesis of a diverse set of biologically important, nitrogen-containing heterocycles. My teaching activities cover all aspects of organic chemistry from basic structure and bonding in organic molecules, to complex organic synthesis. I am a member of the .
Fluorinated Isocyanates: Promising Building Blocks in Organic Synthesis and Preparation of Compounds for Biomedical Applications and Materials Science => pp.
Synthesis of Medium Ring Nitrogen Heterocycles via a Tandem ..
The cyanamide moiety provides many opportunities as a building block for the synthesis of nitrogen-containing heterocycles. This review discusses the reported methods for the preparation of alkyl- and -acylcyanamides and illustrates their reactivity vis-à-vis nucleophilic additions, cycloadditions, radical chemistry and coordination chemistry.1 Introduction2 Biological Relevance of the Cyanamide Moiety3 Access to Cyanamides3.1 Cyanation of Amines3.2 Palladium Catalysis3.3 Deoxygenation of Isocyanates3.4 Desulfurization of Thioureas4 Reactivity of Cyanamides4.1 Nucleophilic Additions4.2 Cycloadditions4.3 Additions to Carbonyl Groups4.4 Chlorinations and Oxidations with -Butyl--chlorocyanamide4.5 Cyanamides as Radical Partners5 Coordination Chemistry of Cyanamides6 Conclusion
Encouraged by all these findings and in continuation of our previous work aimed at the synthesis of a variety of heterocyclic systems for biological and pharmacological evalution [8-27], we report herein a convenient route to several new pyridine-based heterocyclic compounds, via the readily accessible 3-oxo--(pyrid-2-yl) butanamide (1)  as a versatile building block for the title compounds which are expected to have interesting biological activity.
Ring Nitrogen Heterocycles via a Tandem Copper ..
Isocyanides in the Synthesis of Nitrogen Heterocycles ..
A., 2009, Convenient synthesis of novel bis(hydrazone) and bis(indole) derivatives, Heterocycles, 78 (5), 1281- 1288.
Erratum: Boron-nitrogen heterocycles - [PDF Document]
A., 2009, Facile Access to Annulated quinoline and isoquinoline Heterocycles via Their Nitrogen Ylides, J.
Synthesis of N-Heterocycles > Synthesis of imidazolidinones and ..
| Synthesis of nitrogen heterocycles using isocyanates was achieved by organotin reagents and catalysts
Synthesis of Δ 2-Isoxazoline fatty acid ester heterocycles
Ahmed M. Tafesh was born in 1957 in Acre, Israel, and following his arrival in the United States in the fall of 1977, he received his B.S. degree in chemistry at Portland State University in 1981. In 1984 he received his M.S. at Oregon State University in the area of physical organic chemistry working on mechanistic investigation of conjugated carbenes with Professor Peter Freeman. He then moved east to Salt Lake City, where he received his Ph.D. in the area of free radical methodology development as well as the total synthesis of pseudomonic acid under the supervision of Professor Gary Keck. After graduation in 1989 he joined Hoechst Celanese Corp. in Corpus Christi, TX, as a Research Chemist working in exploratory research. In 1991 he was promoted to Research Chemist II and worked on the development of pharmaceutical intermediates. In 1993 he was promoted to Senior Research Chemist and in 1994 he was awarded a two year assignment in Hoechst AG Corporate Research in Frankfurt, Germany. In Germany, Ahmed was active in the area of development of oxidation reagents as well as the development of water soluble catalysts for the reductive carbonylation of aromatic nitro compounds. Ahmed holds more than 20 patents in different areas. Upon completion of his assignment, Ahmed will return to Texas for his new role as a group leader in the area of asymmetric catalysis.
Category:Nitrogen heterocycles - WikiVisually
They have found wide synthetic application, for example in the preparation of amides, esters, peptides, nucleotides, heterocyclic compounds; for the identification of amines, alcohols, and nucleic acids; for the synthesis of bioactive compounds revealing a wide spectrum of biological activity; in the design of effective medicines, herbicides and insecticides; and as chemical intermediates in the production of polyurethane products such as foams, coatings, and elastomers.
Pages in category "Nitrogen heterocycles" ..
In either process, the reagent is the isomeric mixture of the dinitrocompounds, 80% 2,4- and 20% 2,6-, so the product is a mixture of the diisocyanates in the same proportions.
importance of nitrogen heterocycles in ..
Tandem reactions for efficient construction of nitrogen-containing heterocycles were developed. One-pot platinum(II)-catalyzed synthesis of indoles and isoquinolines has been achieved isocyanates, which were derived from a Hofmann-type rearrangement of 2-alkynylbenzamides and 2-alkynylbenzylamides using a hypervalent iodine reagent. As an extension of this approach, -2,3-dihydro-4-quinolones were synthesized acid-catalyzed intermolecular [2+2]-cycloaddition of aldehydes and carbamates, which were formed from nucleophilic addition of alcohols to isocyanate intermediates. Direct, efficient syntheses of the benzimidazo[2,1-]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5- cyclization, oxidative aromatization, and 6- cyclization can be performed in a single synthetic operation.
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