Enamino esters acyclic

By addition of carbocyclic, acyclic and heterocyclic enamino ester to nitroalkenes and subsequent expulsion of the nitro group, pyrrole ester and fused derivatives are accessible82 (equation 58). 

Mteto esters can be obtained by acylation of enamines of acyclic and cyclic ketones with ethyl chloroformate3. Surprisingly no /J-keto ester was obtained when the reaction was carried out in the presence of triethylamine and an extra mole of enamine or a tertiary aromatic amine must therefore be used to neutralize the acid liberated The intermediate enamino ester can be isolated and reduced by hydride donors225 (Scheme 92). 

Vinylogous Carbamate Substrates 4.2.1 Acyclic Enamino Esters... 

The syntheses of /3-enamino esters and related compounds from cyclic and acyclic /3-enamino Meldrums acid derivatives have been described good yields in a range of cases are obtained. In the natural product area, unsaturated esters that are biologically active analogous of leukotriene A4, and a pheromone of the Comstock Mealybug have been synthesized using conventional methods. 

A cycloaddition reaction of the halogen-substituted nitrone (289) with olefins in the presence of AgBp4 provides reactive iminium salts in a regio- and stereo-specific manner. These react with various nucleophiles to give 1,2-oxazine derivatives as shown. In a study of the reactions of P-enamino-esters with carbonyl compounds, WamholF et have isolated a series of acyclic and... 

Pyridones The condensation of dianions of acyclic jS-enamino ketones with esters followed by acid treatment may lead to 4-pyranones (with HCl) or 4-pyridones (with PPA, 70°C). 

The preparation of yS-enamino ketone and esters on solid montraorillonite KIO day coupled with MW irradiation applies to cydic, acyclic and a-chloro-substituted j8-dicarbonyl compounds with amines or their corresponding ammonium acetates (Scheme 8.26) [80]. 

Related mechanochemical protocol was published by Li and collaborators who synthesized a number of p-enamino ketones (esters) 255 in ball mill using acyclic 1,3-diones for substrates without catalyst (Scheme 3.67) [45]. Initial study of reaction... 

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See also in sourсe #XX -- [ ]

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