Home  About us  Contact
 

Primary Nitro Compounds (primary + nitro_compound)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

1,4-Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2006
Luca Cecchi
Abstract The dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. The reactivity of several tertiary amines or azaheteroaromatic compounds containing one or two basic centres is shown to be related to the ability of the protonated base to establish H-bonded ion pairs with the adduct that is formed from the nitronate and the dipolarophile in chloroform. Among the organic bases examined, caged tertiary diamine 1,4-diazabicyclo[2.2.2]octane (DABCO) gave the best results. The reaction is applicable to activated nitro compounds and to phenylnitromethane and affords isoxazoline derivatives in higher yields compared with those of other methods. The reaction, however, is not compatible with nitroalkanes. The proposed mechanism of the reaction is based on the collapse of the H-bonded ion pair. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

ChemInform Abstract: General Synthesis of ,-Functionalized ,-Aryl-Substituted Primary Nitro Compounds.

CHEMINFORM, Issue 41 2001
A. A. Tishkov
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Synthesis of 4,5-Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System

CHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2008
Luca Cecchi Dr.
Abstract A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primary nitro compounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activated nitro compounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles in the presence of the base alone, undergo the reaction on addition of a copper(II) catalyst. The observed occurrence of induction periods in most reactions is ascribed to an equilibrium preceding the rate-determining step, and gives a hint as to the proposed reaction mechanism. The results indicate that this method might be of practical and general utility for synthetic practice. E, descritta una nuova procedura sintetica per la preparazione di 4,5-diidroisossazoli attraverso la condensazione di nitrocomposti primari con olefine. Il metodo si basa sull,utilizzo di un sistema catalitico costituito da rame(II) accompagnato da una base organica. L,effetto catalitico dei sali di rame(II) è stato evidenziato confrontando le velocità di conversione per alcune reazioni modello. Infatti, i nitrocomposti attivati reagiscono più velocemente che non in sola presenza di ammine terziarie mentre i nitroalcani, i quali non condensano con i dipolarofili in presenza della sola base, reagiscono per aggiunta di rame(II). Queste reazioni di condensazione hanno mostrato la presenza di tempi d,induzione variabili in funzione dei substrati e della tipologia di rame utilizzata. Il tempo d,induzione è imputabile a pre-equilibri che precedono lo stadio lento della reazione e sono in accordo con il meccanismo di reazione proposto. I risultati ottenuti mostrano che questo metodo è pratico e di utilità generale per la sintesi organica. [source]

1,4-Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2006
Luca Cecchi
Abstract The dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. The reactivity of several tertiary amines or azaheteroaromatic compounds containing one or two basic centres is shown to be related to the ability of the protonated base to establish H-bonded ion pairs with the adduct that is formed from the nitronate and the dipolarophile in chloroform. Among the organic bases examined, caged tertiary diamine 1,4-diazabicyclo[2.2.2]octane (DABCO) gave the best results. The reaction is applicable to activated nitro compounds and to phenylnitromethane and affords isoxazoline derivatives in higher yields compared with those of other methods. The reaction, however, is not compatible with nitroalkanes. The proposed mechanism of the reaction is based on the collapse of the H-bonded ion pair. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Synthesis of 4,5-Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System

CHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2008
Luca Cecchi Dr.
Abstract A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primary nitro compounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activated nitro compounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles in the presence of the base alone, undergo the reaction on addition of a copper(II) catalyst. The observed occurrence of induction periods in most reactions is ascribed to an equilibrium preceding the rate-determining step, and gives a hint as to the proposed reaction mechanism. The results indicate that this method might be of practical and general utility for synthetic practice. E, descritta una nuova procedura sintetica per la preparazione di 4,5-diidroisossazoli attraverso la condensazione di nitrocomposti primari con olefine. Il metodo si basa sull,utilizzo di un sistema catalitico costituito da rame(II) accompagnato da una base organica. L,effetto catalitico dei sali di rame(II) è stato evidenziato confrontando le velocità di conversione per alcune reazioni modello. Infatti, i nitrocomposti attivati reagiscono più velocemente che non in sola presenza di ammine terziarie mentre i nitroalcani, i quali non condensano con i dipolarofili in presenza della sola base, reagiscono per aggiunta di rame(II). Queste reazioni di condensazione hanno mostrato la presenza di tempi d,induzione variabili in funzione dei substrati e della tipologia di rame utilizzata. Il tempo d,induzione è imputabile a pre-equilibri che precedono lo stadio lento della reazione e sono in accordo con il meccanismo di reazione proposto. I risultati ottenuti mostrano che questo metodo è pratico e di utilità generale per la sintesi organica. [source]