Alain Reliquet

ADDITION OF ORGANOMETALLICS ON α,β-UNSATURATED THIOCARBONYL COMPOUNDS II. MICHAEL ADDITION OF LITHIUM ENOLATES ON THIOAMIDE AND DITHIOCARBAMATE VINYLOGS AND THIOAROYLFORMAMIDINE

Abstract α,β-Unsaturated thiocarbonyl compounds substituted by a secondary amino group in position β, such as thioamide vinylogs, dithiocarbamate vinylogs or thioaroylformamidines react with lithium enolates of esters, ketones or amides to give 1,4-addition compounds. In the presence of magnesium bromide 1,4-adducts undergo an intramolecular cyclization to give 2H-thiopyranones. Methylation of the 1,4-adducts is followed by a stereospecific elimination of the amine and leads to (1-Z)-1,3-dienic carbonyl compounds: with thioamide vinylogs, δ-methylthio-α,β,γ,δ-diethylenic ketones, esters and amides are obtained. Dithiocarbamate vinylogs give the α-ethylenic ketene dithioacetals, with a carbonyl function in δ-position. Substituted dihydrothiophenes and thiazolines are prepared by the reaction of ethyl α-chloro-α-lithiopropionate with aminopropenethione and thioaroylformamidine respectively.

Efficient regioselective synthesis of triheterocyclic compounds: imidazo[2,1-b]benzothiazoles, pyrimido[2,1-b]benzothiazolones and pyrimido[2,1-b]benzothiazoles

The preparation and characterisation of triheterocyclic compounds, via annulation reactions, are described. Amidines 1 reacted with substituted bromomethyl compounds, acid chlorides, and acrylic dienophiles to afford the corresponding imidazo[2,1-b]benzothiazoles 2 and pyrimido[2,1-b]benzothiazoles 3 or 4.

Alkylation des carbenoides par des nucleophiles. : II. Substitution nucleophile de l'halogene de carbenoides α phosphonates catalysee par le cuivre(I)

Abstract The addition of a catalytic amount (12%) of a copper(I) salt to a mixture of an α-lithio-α-chloroalkylphosphonate and an alkyllithium RLi or a Grignard reagent RMgX leads to the formation of a new organometallic reagent in which the R group has replaced the chlorine atom of the carbenoid. This nucleophilic alkylation of carbenoids can be performed with secondary-alkyl Grignard reagents, and with aryllithium, alkenyllithium and alkynyllithium reagents in good yields (60–80%).

Alkylation des carbenoides par des nucleophiles: I. Alkylation de carbenoides α esters et α phosphonates par des cuprates symetriques et dissymetriques

Abstract The electrophilic character of carbenoids can be activated by addition of organocopper reagents (RCu, R 2 CuM, or RCuZM), forming an unsymmetrical cuprate. Internal substitution of the carbenoid halogen by the R group leads to a new alkylated unsymmetrical cuprate reagent. R can be primary, secondary, or tertiary alkyl, aryl, thiophenyl.

2-HYDRAZONOPHENYLTHIOACETAMIDES, INTERMEDIAIRES DE LA SYNTHESE DE SELS DE THIADIAZOLIUM ET DE THIADIAZOLINES

Abstract 2-Hydrazonophenylthioacetamides are obtained in three steps from methylbenzoylformate. First, stereochemicals problems relating to the structure of these heteroatomic chains are discussed, then reactions allowing their conversion into 1,2,3-thiadiazolium salts and 5-imino-Δ3-1,2,3-thiadiazolines are described. Les 2-hydrazonophenylthioacetamides sont obtenus en trois etapes a partir du benzoylformiate de methyle. Apres avoir discute des problemes stereochimiques poses par la structure de ces enchainements, nous decrivons les reactions qui permettent de les transformer en sets de 1,2,3-thiadiazolium et en 5-imino-Δ3-1,2,3-thiadiazolines.

Addition of organometallics to α,β-unsaturated thiocarbonyl compounds. III: Michael addition of active methylene compounds to thioamide and dithiocarbamate vinylogs

Abstract α,β-Unsaturated thiocarbonyl compounds substituted by a secondary amino group in position β, such as thioamide and dithiocarbamate vinylogs, react with sodium derivatives of active methylene compounds CH2XY to give 1,4-addition compounds. Methylation of the 1,4-adducts is followed by elimination of the amine and leads to conjugate thioethers and ketene dithioacetals with functional groups X and Y at the end of the chain. Cyclization and hydrolysis of the adduct afford 2H-thiopyran derivatives.

1,2-Bis[(2-dimethylamino-2-thioxo-1-phenylethylidene)hydrazino]ethane: a new tetradentate ligand for Ni2+

The preparation of a new type of N2S2 tetradentate ligand 3 with the bis(hydrazonothioamide) structure is reported in this paper. The key step in this synthesis is the condensation of the dihydrazine 7 with an α-ketoester. Ligand {1,2-bis[(2-dimethylamino-2-thioxo-1-phenylethylidene)hydrazino]ethane} 3 was obtained in 6 steps from secondary amine. This ligand is then used in the preparation of a nickel(II) complex 4 and the mesomeric forms of metallic complex NiN2S2 are discussed.

Synthesis of new chiral and nonchiral N2O2 and N2S2 tetradentate ligands and their metal complexes

N,N′-Bis(3-aryl-3-oxoprop-1-enyl)diamines and N,N′-bis(3-aryl-3-thioxoprop-1-enyl)diamines are synthesised by condensation of chiral or nonchiral diamines on the corresponding functionalised ketoenolate 2 or dithiolylium salt 4. Complexation of the obtained N2O2 and N2S2 ligands with transition metals is investigated.