Angel Alberola

Versatility of Weinreb amides in the Knorr pyrrole synthesis

Abstract N -Methoxy- N -methyl-α-enaminocarboxamides were prepared starting from enamines and Weinreb α-aminoamides. Their reaction with oganometallic compounds and subsequent cyclization constitute a versatile alternative in the Knorr pyrrole synthesis.

Synthesis of [1]benzopyrano[4,3-b]pyrrol-4(1H)-ones from N(α)-(2-oxo-2H-1-benzopyran-4-yl)weinreb α-aminoamides

Abstract N(α)-(2-Oxo-2H-1-benzopyran-4-yl)Weinreb-α-aminoamides were prepared from 4-chlorocoumarin and α-aminoacid derivatives. Their reaction with organometallic compounds (RLi or RMgBr) and subsequent cyclization of ketones thus obtained, give [1]benzopyrano[4,3-b]pyrrol-4(1H)-ones. Starting from proline derivatives, simultaneously with the pyranone-pyrrole fusion, we establish an interesting procedure for the formation of pyrrolizines.

The Reaction of b-Aminoenones with a-Amino Derivatives. Synthesis of 2-Functionalized Pyrroles

β-Aminoenones react with ethyl glycinate, α-aminoacetonitrile and α-aminoacetamide hydrochlorides leading to 2-functionalized pyrroles. Although the transamination is a high-yield process, the transformation of the intermediate, in both basic or thermally induced conditions, affords the corresponding pyrroles in poor to moderate yields

Synthesis of Z-β-siloxyacrylonitriles and study of their dienophilic properties

Abstract A general method for the synthesis of Z-β-siloxyacrylonitriles from isoxazoles is reported. Their dienophilic activity is also described.

Ring Cleavage of N-Alkylisoxazolium Salts by Lithium Dialkylcuprates: Synthesis of β-Enaminoketones

Abstract N-Alkylisoxazolium salts undergo ring cleavage when treated with lithium dialkylcuprates to give β-enaminoketones in high yields.

Cyanogen Bromide as a Useful Brominating Agent, Synthesis of α-Bromo-β-Aminoenones

Abstract Cyanogen bromide reacts with β-aminoenones, in very mild conditions, leading to α-bromo-β-aminoenones with excellent yields.

Regioselective Synthesis of 2-Functionalized Thiophenes by Condensation of α-Mercapto Compounds with β-Aminoenone Derivatives

Abstract 2-Acylthiophenes and ethyl 2-thiophene-carboxylates are prepared regioselectively by reaction of 3-ctil oroenones and 2-acylenammoni urn chlorides with α-mercapto derivatives in good to moderate yields.

The Reaction of β-Aminoenones with Cyanamide. A High Efficient Synthesis of 2-Aminopyrimidines

Abstract β-aminoenones react with cyanamide, molar ratio 1:2, to yield 2-aminopyrimidines in nearly quantitative yields.

3, 5-Dimethyl-4-Isothiazolylmagnesium Iodide and its Reactions with some Electrophilic Reagents

Abstract As a route to 4-alkyl-, 4-alkenyl- and 4-hydroxyalkyl-isothiazoles, 3,5-dimethyl-4-isothiazolylmagnesium iodide has been obtained, and its reactions with organic halides, oxocompounds and nitriles have been studied.

Regioselective Synthesis of 2- and 3-Acylpyrroles by Reaction of b-Aminoenones with a-Aminoketone Hydrochloride

A high regioselective synthesis, with good to excellent yields, of 2- and 3-acylpyrroles from β-aminoenones and α-aminoketones is described. The formation of 2-acylpyrroles or their 3-acylisomers depends on the pattern substitution on the reactants