Results 61 to 70 of about 46,002 (241)

Prins fluorination cyclisations: Preparation of 4-fluoro-pyran and -piperidine heterocycles

open access: yesBeilstein Journal of Organic Chemistry, 2010
The Prins reaction was investigated using BF3·OEt2 as a Lewis acid. It has been recently demonstrated, that if BF3·OEt2 is used in stoichiometric amounts then these reactions generate fluorinated products where the BF3·OEt2 contributes fluoride ion to ...
Guillaume G. Launay   +2 more
doaj   +1 more source

Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom

open access: yesBeilstein Journal of Organic Chemistry, 2020
The tandem gold(I)-catalyzed rearrangement/Nazarov reaction of enynyl acetates in which the double bond is embedded in a piperidine ring was computationally and experimentally studied.
Giovanna Zanella   +4 more
doaj   +1 more source

Metalloamination/Cyclization of Zinc(II) Amides Derived from N,N-Dimethylhydrazinoalkenes—Applications for the Direct C-SP2 Functionalization of Aryl and Vinyl Electrophiles

open access: yesInorganics
Treatment of N,N-dimethylhydrazinoalkenes with diethylzinc followed by exposure of the resulting ethylzinc amides to high vacuum drives a Schlenck redistribution metalloamination/cyclization to generate the corresponding bis(organozinc) intermediates in ...
Jérome Lépeule   +2 more
doaj   +1 more source

Opportunities and challenges for direct C–H functionalization of piperazines

open access: yesBeilstein Journal of Organic Chemistry, 2016
Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule pharmaceuticals. Herein we summarize the current synthetic methods available to perform C–H functionalization on piperazines in order to lend ...
Zhishi Ye, Kristen E. Gettys, Mingji Dai
doaj   +1 more source

New One-Pot Methodologies for the Modification or Synthesis of Alkaloid Scaffolds

open access: yesMarine Drugs, 2010
There are several avenues by which promising bioactive natural products can be produced in sufficient quantities to enable lead optimization and medicinal chemistry studies. The total synthesis of natural products is an important, but sometimes difficult,
Amir E. Wahba, Mark T. Hamann
doaj   +1 more source

Diastereoselective synthesis of some novel benzopyranopyridine derivatives

open access: yesBeilstein Journal of Organic Chemistry, 2006
BackgroundThe formation of novel N-substituted-1,2,3,4-tetrahydro[1,3]-dioxolo-[6,7]-5H-[1]benzopyrano [3,4-c]pyridines were observed unexpectedly during the acid-mediated ketal removal of ethylenedioxy ketal protected 4-piperidones.
Pradeep K. Mohakhud   +6 more
doaj   +1 more source

The Synthesis and Biological Activity of 1-Alkyl-4-(3-azacyclobenzoyl)-5-hydroxypyrazole Herbicides

open access: yesCHIMIA, 2003
The benzoylpyrazoles belong to a class of herbicides that inhibit the enzyme 4-hydroxy-phenylpyruvate dioxygenase (HPPD). This mode of action is characterized by bleaching due to the disruption of plastoquinone and ?-tocopherol biosynthesis ...
Zoltan Benko   +8 more
doaj   +1 more source

Home - About - Disclaimer - Privacy