Nouvelle méthode de synthèse de thiazolopyridines

It has been established that the direct condensation between aromatic and aliphatic thioesters and the variously generated anion of amino-chloropyridines represents the best method for the synthesis of thiazolo-pyridines. The transient thioamides, sometimes isolated, can be easily converted chemically or photochemically into the desired fused heterocycles.     

Nouvelle voie de synthèse des dérivés de l'ellipticine et analogues alcaloïdes à activité antitumorale

A new snythesis of 6H-pyrido[4,3-b]carbazoles is described starting from substituted cyclohexanones involving the combination of Borsche's carbazole preparation and Cranwell and Saxton's ellipticine synthesis where the starting materials are easily available. The dehydrogenation step is accomplished at an early stage. In some cases (11-desmethyl ellipticines derivatives), 7H-pyrido[3,4-c]carbazoles were also obtained.     

Nouvelle synthèse des composés polysubstitués d'esters de l'acide pyrrolecarboxylique-3 par réarrangement d'époxy-1,2 pyrrolidines

In presence of acides (HF/pyridine) substitutes 3-ethoxycarbonyl-6-oxal-azabicyclo[3.1.0[hexanes 1 afforded subtituted 3-ethoxycarbonyl-pyrroles 3 in stereospecific manner. Spiro substrates gave polycyclic product under the conditions used.     

Nouvelle synthèse des pyrido[4,3-b]quinoléines substituées sur leur sommet 1

A three step synthesis of pyrido[4,3-b]quinolines is reported. Thus, treatment of 2-hydroxy-4-arylaminopyridines under Vilsmeir-Haack conditions directly afforded 1-oxo-1,2-dihydropyrido[4,3-b]quinolines. Chlorination of these compounds gave the corresponding 1-chlorinated derivatives which were then substituted by various primary and secondary amines.     

Recherches en vue de la synthèse de barbiturates organostanniques

Triphenyl and tributyltin hydrides have been found to add to the terminal double bond of unsaturated ethyl malonates to give organotin substituted ethyl malonates. Attempted cyclisation of the latter into barbituric compounds failed.     

Sur la synthèse d'acides thiazolotriazolylacétiques

During the synthesis of thiazolotriazolylacetic acids, the condensation of ethyl 4-chloro-3-oxobutyrate with triazolinethiones was studied. The use of an alkaline reagent (triethylamine) leads only to S-alkylation and not to the expected cyclized product. The cyclization of the intermediate β-ketoester is observed only by use of acidic reagents (phosphorous oxychloride, hydrogen chloride).     

Sur les esters activés III. Nouvelle synthèse des dioxo-2,5-pipérazines et étude de leurs propriétés chimiques

By reacting an α-amino acid N-carboxyanhydride with an amidoxime the dioxopiperazine derived from the parent amino acid is formed in quantitative yield. In this way the dioxopiperazine of glutamic acid, which is not otherwise accessible, has been prepared.     

Synthèses d'indoles par cyclisation réductrice. II Nouvelle mélhode de synthèse des indole carboxamides-3, donnant accés aux dérivés de la gramine

A new synthetic method for 3-indolecarboxamides, in two steps from 2-halogenonitrobenzenes, is reported. These benzene derivatives, reacting with sodium salts of cyanoacetamides in N,N-dimethylformamide, give 2-(2-nitrophenyl)cyanoacetamides. Catalytic hydrogenation of the nitro derivatives, at 80°, leads directly to 3-indolecarboxamides. Reduction of the amides by lithium aluminium hydride gives finally 3-aminomethylindoles (gramine and its derivatives), so obtained by a new synthetic route.     

Sur la synthèse de quelques furochromènes,analogues pharmacochimiques de la xanthylétine et de la séseline

Some furochromenes substituted at the 2-position by an electron-attracting group were obtained starting from ortho-hydroxyformyl derivatives of 2,2-dimethyl-2H-chromene following various processes which are indicated. These new furochromenes are pharmacochemical analogues of some natural pyranocoumarins, and as such they are potential photosensitizers.     

Les anions-radicaux de l'isoprène et du butadiène intermédiaires de synthèse en chimie organique

We have synthesized a series of alkadiene and dialcohol homologs of terpenoid natural products by using anion-radicals of isoprene and butadiene. The reactions of the two monomers were initiated anionically by use of alkali metal–aromatic hydrocarbon complexes. The polymerization was stopped at the dimer stage. This method constitutes a route of synthesis for numerous organic compounds, such as alcohols and hydrocarbons.     

Etude de la réactivité de la fonction carbonyle avec le cétène en présence d'un alcoxyde de titane. 1ère communication. Nouvelle méthode de synthèse de β-hydroxyesters

A new synthesis of β-hydroxyesters involving a reaction between a carbonyl compound, ketene and an alkyl-orthotitanate is described. The following carbonyl compounds have been studied: aldehydes, ketones, α-diketones, α- or γ-ketoesters. A reaction mechanism is proposed.     

Addition d'hétérocycles azotés aux alcynes arylés; synthèse de N-styrylazoles

Azoles (pyrazoles imidazoles) add to the triple bond of phenyl-acetylene and phenylmethylacetylene according to stereoselective and sterospecific addition. In this manner various styrylazoles have been synthesized.     

Sur une méthode générale de synthèse des pyridones-2 condensées

Condensed 2-pyridones have been prepared by thermal cyclization of vinyl isocyanates substituted in β-position with aromatic heterocyclic radicals.     

Nucléosides de synthèse XXI. Obtention spécifique de ribonucléosides de configuration anomérique α

A new and stereospecific synthesis of a chemical precursor of α-D-ribonucleosides, namely, 1-α-D-ribofuranosyl-4-carboxamido-5-aminoimidazole ( 1 ) is described using 2-thio-α-D-ribofurano[1,2-d]-oxazolidine as the starting material.     

Utilisation de techniques d'amination réductrice pour la synthèse d'amino-sucres de différents types. Communication préliminaire

Synthesis of amino-sugars using reductive amination reactions. Preliminary communication Treatment of aldehydo- or keto-sugars with primary or secondary amines and hydrogen in the presence of a catalyst (Pd/C) gave with good to excellent yields (67–96%) the expected secondary or tertiary amines. Primary amines can be obtained by using benzylamine, a hydrogenolysis taking place during the reaction.     

Isolement de nouveaux complexes de zinc de dipyrrométhènes formés au cours de la synthèse de la méso-tétramésitylporphyrine par la réaction de Rothemund

Three new zinc bis(dipyrromethene) complexes have been isolated in the preparation of meso-tetramesitylporphyrin by the Rothemund zinc template based condensation process.     

Une synthèse générale des tétraazamacrocycles mono-C-fonctionnalisés

A General Synthesis for Mono-C-Functionalized Tetrazamacrocycles A new synthesis, under usual conditions of concentration, medium, and temperature, of a series of mono-C-functionalized tetraazamacrocycles is given. The method may easily be generalized. The new procedure allows the modification of the length of the side-chain or the size of the cavity by choosing fitted staring materials. The key intermediate has a tosylated linear side-chain susceptible to be transformed into a large variety of functional groups.