- Chemoselective Intramolecular Functionalization of Methyl Groups in Nonconstrained Molecules Promoted by N-Iodosulfonamides
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Mechanistic evidence observed in Hofmann-L?ffler-Freytag-type reactions has been crucial to achieve the chemoselective functionalization of methyl groups under mild conditions. Radical-mediated methyl iodination and subsequent oxidative deiodination are the key steps in this functionalization, where iodine chemistry has a pivotal role on the formation of the C-N bond. The concepts of single hydrogen atom transfer (SHAT) and multiple hydrogen atom transfer (MHAT) are introduced to describe the observed chemoselectivity. (Chemical Equation Presented).
- Paz, Nieves R.,Rodríguez-Sosa, Dionisio,Valdés, Haydee,Marticorena, Ricardo,Melián, Daniel,Copano, M. Belén,González, Concepción C.,Herrera, Antonio J.
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supporting information
p. 2370 - 2373
(2015/06/02)
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- USE OF ENANTIOPURE N-SULPHONYL PYROGLUTAMIC ACID AS RESOLVING AGENT
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Use of enantiopure N-sulphonyl pyroglutamic acid as resolving agent for the separation of enantiomers by crystallization or precipitation.
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Page/Page column 4-5
(2009/07/25)
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- Synthesis, screening and quantitative structure-activity relationship (QSAR) studies of some glutamine analogues for possible anticancer activity
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We described the syntheses, biological activities and QSAR studies of 36 new 5-n-substituted-2-(substituted benzenesulphonyl) glutamines 6-41 with different substitutions. These compounds were designed as structural analogues of most reactive amino acid, 'glutamine' (GLN), especially in the tumor cells. They present the new basic lateral chains at R5 position as well as different substitutions at 2′, 3′, 4′, and 5′ positions on the benzene ring. The synthesized compounds have been tested for antitumor activity against Ehrlich ascites carcinoma (EAC) in Swiss albino mice using percentage inhibition of tumor weight as inhibitory parameter. In order to elucidate the structural requirements for antitumor activity, quantitative structure-activity relationship (QSAR) studies have been performed using extra thermodynamic model of Hansch. QSAR equations showed that the electronic parameter (σ) on the aromatic ring system, steric parameter (Es) and to some extent Sterimol length of the substituent (L) on the aliphatic side chain correlate significantly with the antitumor activity. Resonance factor occupies the major electronic contribution on the aromatic ring system to the activity.
- Srikanth,Kumar,Ghosh, Balaram,Jha, Tarun
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p. 2119 - 2131
(2007/10/03)
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- A MILD AND EFFICIENT METHOD FOR THE PREPARATION OF N-TOSYL AMIDES AND LACTAMS
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N-tosyl amides and lactams can be prepared easily and under mild conditions by the inter- or intramolecular condensation of carboxylic acids and secondary sulfonamides.The coupling reagent used is dicyclohexylcarbodiimide (DCC) in the presence of 4-pyrrolidinopyridine (4-PPY) and the reactions proceed readily, usually in high yield, at room temperature.
- Tanner, David,Somfai, Peter
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p. 613 - 618
(2007/10/02)
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