Etudes conformationnelles par Résonance Magnetique Nucléaire et variations de températures d'éthanes di- et trisubstitués

In this paper we report the conformational analysis of several di- or trisubstituted ethanes substituted by the following groups: N-dialkly, thioalkyl, alkoxy, N-pyrrolidino, N-benzyl, nitrile or carbomethoxy. Spectra were calculated by a method based on chemical shifts. Relative stabilities of rotamers were discussed in relation to structural parameters (geometrical and electronic).     

Régiospécificité de la cycloaddition des diarylnitrilimines sur quelques dérivés indoliques

In this paper, we describe the results of a study of the reaction of diaryl nitrilimines with N-ethylindole ( 1 ) and 2-methoxycarbonyl-N-ethylindole ( 2 ). The regioselectiivity of the reaction is reversed when going from 1 to 2 as it has been spectroscopically and chemically demonstrated.     

Réarrangement de thiénobenzothiépinones en thiénoisothiazolinone et benzoisothiazolinone

Under the conditions of the Schmidt reaction the thienobenzothiepinones 1 , 2 and 13 involve a rearrangement respectively in N-benzythieno[2,3-d]isothiazolin-3-one ( 5 ) and benzoisthiazolin-3-one ( 6 ). A mechanism for this rearrangement is proposed.     

Etude dans la série des pyrrolidinones. IV. Formation de quelques dérivés de l'acide L méthylène bis N-(oxo-5 pyrrolidine carboxylique-2)

Starting from the readily available 5-oxo-2-carboxypyrrolidine, methylene-bis-(N-5-oxo-2-carboxypyrrolidine) was prepared and transformed into a diamine, then into two isomeric diols, which cyclised into one ether. The meso configuration has been assigned for this ether. The reduction of both diols and ether was complete and gave rise to methylene-bis-N-pyrrolidine.     

Sur le mécanisme de la réaction de meth-cohn-tarnowski de préparation des thiocoumarines

Reaction of 2-t-butylthiobenzaldehyde with N-(2-dialkylaminoethyl)-cyanacetamides followed by heating of the resulting 3-(2-t-butylthiophenyl)-2-cyanoacrylamides in polyphosphoric acid leads to the formation of 3-carboxamido-2-imino-2H-benzo[b][l]thiopyrann intermediates which afford thiocoumarins on hydrolysis. The authors postulate the intermediate formation of a thiophenate ion by an electronic mechanism involving six centers.     

Réaction de l'azaallyllithium en série acétylénique: Une méthode directe de préparation de phényléthynyl pyrrolidines, -pyrrolines et -pyrroles N-non substitués et N-alkylés

Cycloaddition of 1,3-diphenyl-2-azaallyllithium to tolane, diphenylbutadiyne and 1,4-diphenylbutenyne E produces quantitatively 2,3,4,5-tetraphenylpyrrole, 3-phenylethynyl-2,4,5-triphenyl-3-pyrroline and 3-phenylethynyl-2,4,5-triphenylpyrrolidine, respectively. Treatment before hydrolysis with benzyl bromide or dimethl sulfide gives N-alkyl-substituted derivatives. The structure of 3-pyrrolines was established by spectral data and chemical correlations. Stereochemical courses of this new synthetic method for 3-pyrrolines are discussed.     

Synthèse et réactions de didésoxy-5,6-halogéno-6-α-D-xylo-hepténo-5-furannurononitriles. Communication préliminaire

Synthesis and reactions of 5,6-dideoxy-6-halogeno-α-D-xylo-hept-5-eno-furanurononitriles The 5,6-dideoxy-6-chloro-, 6-iodo- and 6-fluoro-3-O-methyl-α-D -xylo-hept-5-eno-furanurononitriles have been prepared, their properties described as well as the methods used for the assignment of the configuration of the geometrical isomers. Some new reactions of the 6-bromo analog ( 1 ) of these compounds are reported. For example, when reacted with 2-mercaptoethanol or N,N′-dimethyl-ethylenediamine in the presence of NaOH, 1 gave the corresponding six-membered ring, stereo-isomers of an oxathiane or of a perhydrodiazine respectively. When the base used was Et₃N and the binucleophile the N-methyl-ethanolamine or the N,N′-dimethyl-ethylene-diamine the major product was a cyano-enamine which could be hydrolysed to a β-cyanoketone or cyclized to a five-membered ring, an oxazolidine or an imidazolidine respectively.     

Photochimie d'hétérocycles azotés. IV. Transposition de type photo-fries des N-acétyl benzimidazolones

The photolysis of benzene or alcoholic solutions of N-acetyl-and N,N-diacetylbenzimidazolones gave mixtures of ortho- and para-rearrangements products accompanied to some extent with de-N-acylation. The different products have been identified by means of nmr, mass spectrometry and unambiguous synthesis.     

Action de 3-hydrazino-2-(N,N-dialkylaminométhyl)propanenitriles sur quelques iminoesters N-fonctionnalisés : synthèse de dérivés triazoliques

Reaction of 3-hydrazino-2-(N,N-dialkylaminomethyl)propanenitriles with a series of N-functionalized iminoesters: Synthesis of triazolic compounds. The reaction of 3-hydrazino-2-(N,N-dialkylaminomethyl)propanenitriles with a series of N-functionalized iminoesters leads to the formation of triazolones and triazoles. The latter, presenting two reactive sites in positions 1 and 6, undergo intramolecular cyclization, to form triazolopyrimidine in good yields.     

Alcoylation d'acridanone-9. Premiers exemples de O-alcoylation dans cette série de composés

The results of nucleophilic substitution of the 2-methoxy-9-acridone are discussed in terms of competition between both ionic sites N^? and O^?, of the molecule. They are the first examples of O-alkylation of substituted 9-acridone.     

Processus de rotation empêchée autour de plusieurs liaisons dans les sels de (N,N-diméthylamino-1 propényl-1-ylidène-3) diméthylammonium

The structural identification of some N,N-dimethyl-aminopropenylylidene-dimethylammonium salts has been achieved by NMR and UV spectrographic studies. Several processes of hindered rotation around C? N and C? C bonds are demonstrated. Free activation enthalpies are determined and discussed in terms of effects of the substituent, anion and solvent.     

Action de nucléophiles simples sur un bromoénurononitrile,précurseur et équivalent synthétique partiel d'un ynurononitrile

Reactions of Mononucleophiles with a Bromoenurononitrile, Precursor and Partial Synthetic Equivalent of an Ynurononitrile Several mononucleophiles (bases) have been reacted with one or the other of the geometrical isomers of the bromoenurononitrile 1. Depending on the nucleophile and the conditions, many different mechanistic pathways were followed, f. ex.: with OH^?, stereospecific elimination from (Z)- 1 leading to 2 , with N^?₃ and F^?, stereospecific E-A_N reactions leading from (Z)- 1 to (Z)- 8 and (Z)- 12 respectively, with PhCH₂SH, conjugate nucleophilic addition to 7, with Me₂NH, conjugate nucleophilic addition followed by a S_N2 to 11 , as well as several cases of nonstereoselective, probably A_N-E, reactions leading to 3,6,9 and 10. In spite of their diversified reactivity, bromoenurononitriles like 1 , partial synthetic equivalent of 2 , constitute useful synthetic intermediates.     

Synthése,stéréochimie,et réactivité thermique de (N-méthylidenealkylamino)-2 aziridines

1-Alkyl-2-(N-methylidenealkylamino)aziridines are obtained by the reaction of primary amines with either α-chloroacraldehyde or α-chlorocrotonaldehyde. Structural assignments are made by nmr spectroscopy. The thermal rearrangement of 1-alkyl-2-(N-methylidenealkylamino)-3-methylaziridines to pyrroles is described.     

Synthèse de spirohydantoines dérivées du diphényl-2,4-aza-3-bicyclo-[3.3.1]nonane et du diphényl-7,9-aza-8-bicyclo[4.3.1]decane par réaction de Bucherer dans la N,N-diméthylformamide: Influence de la température et cours stéréochimique. Communication préliminaire

Synthesis of Spyrohydantoines Derivatives of 2,4-Diphenyl-3-azabicyclo[3.3.1]nonane and 7,9-Diphenyl-8-azabicyclo[4.3.1]decane via Bucherer Reaction in N,N-Dimethylformamide: Influence of the Temperature and Stereochemical Path The unreactives ketones related to 2,4-diphenyl-3-azabicyclo [3.3.1]nonan-9-one to the Bucherer reaction in usuals conditions show excellent reactivity in DMF. as unique solvant. The stereochemical paths of these reactions and the synthetic utility of the temperature modification are described.     

Alkylation en catalyse par transfert de phase d'une série d'acridanone-9 substituées: Compétition entre O- et N-alkylation

Substituted acridanones were alkylated under phase transfer catalysis conditions. In so doing, a mixture of O- and N-alkyl derivatives was prepared. Orientation of the reaction products depends upon the alkylating agent but not on the position of the substituent. Hence, HSAB principles can explain this orientation.     

Recherche d'analogues de nucléosides à activité antivirale

Search for Antiviral Nucleosides Analogues In contrast to the reported impossibility of obtaining the expected products when 1-(2,3-O-isopropylidene-1,5-dialdoribofurannos-1-yl)uracile ( 2 ) was treated with stabilized ylides, we prepared in good to excellent yields the modified nucleosides 4–9 by reaction of 2 respectively with acetylmethylidene-, benzoylmethylidene-, ethoxymethylidene-, methoxymethylidene-, succinimidylidene- or N-phenylsuccinimidylidene-triphenylphosphorane. Compounds 4–10 were tested against the herpes virus type 1 (HF) and influenza virus A₂/Scotland. The modified nucleoside 9 showed a limited but significative activity against the herpes virus.     

Régio et périsélectivité de réactions de diels-alder et des cycloadditions dipolaires-1,3 avec une triazépine-1,2,4: Approche théorique

e.s The cycloaddition of 1,3-dipoles (mesitonitrile, C,N-dimethylnitrone) and various dienophiles (DMAD, maleic anhydride) to 1,2,4-triazepine 1 are peri and regiospecific. Nitrone excepted the preferred orientation of addition is predicted correctly by FMO/MNDO calculation.     

Complexation du 2‐[(5‐méthyl­pyrazolyl)méthyle]benzimidazole par les chlorures de cuivre et de cadmium

The structures of dichloro{2‐[(5‐methyl‐1H‐pyrazol‐3‐yl‐κN²)methyl]‐1H‐1,3‐benzimidazole‐κN³}copper(II), [CuCl₂(C₁₂H₁₂N₄)], and di‐μ‐chloro‐bis(chloro{2‐[(5‐methyl‐1H‐pyrazol‐3‐yl‐κN²)methyl]‐1H‐1,3‐benzimidazole‐κN³}­cadmium(II)), [Cd₂Cl₄(C₁₂H₁₂N₄)₂], show that these compounds have the structural formula [ML(Cl)₂]_n, where L is 2‐[(5‐methylpyra­zolyl)methyl]benzimidazole. When M is copper, the complex is a monomer (n = 1), with a tetrahedral coordination for the Cu atom. When M is cadmium (n = 2), the complex lies about an inversion centre giving rise to a centrosymmetric dimer in which the Cd atoms are bridged by two chloride ions and are pentacoordinated.     

Action de l'anhydride acétique sur les (aziridinyl-1)-2 tétra-hydropyrannes et sur les dialkylamino-2 tétrahydropyrannes: Influence des substituants de l'azote sur l'orientation de la réaction

The 2-(1-aziridinyl)tetrahydropyrans cannot be obtained by aminolysis of the 2-dialkylaminotetrahydropyrans. These compounds are synthesized by the Hofmann reaction between 2-chlorotetrahydropyrans and ethylenimine. The effect of acetic anhydride on the 2-(1-aziridinyl) and 2-dialkylaminotetrahydropyrans was studied. The 2-dimethylaminotetrahydropyrans were converted into 2-acetoxytetrahydropyrans and dimethylacetamide by cleavage of the carbon-nitrogen bond. Ring opening of the oxygen heterocycle gives the corresponding dialkylacetamides and polymerised products. The 2-(1-aziridinyl)tetrahydropyrans allow the synthesis of the N-(2-tetrahydropyrannyl)-N-(2-acetoxy-ethyl)acetamides. Acetic anhydride ring opens the nitrogen heterocycle.     

Réactions de substitution nucléophile de l'hydroxyurée. Synthèse et étude des oxa-6 dihydrouraciles

Hydroxyurea, an N-protected hydroxylamine, reacts with α-bromoesters to give α-ureidoxyesters. Some of these have been isolated. Their cyclisation is a synthetic route to 6-oxadihydrouraciles which structure has been well established by means of physicochemical methods. Especially, ¹³C nmr spectroscopy has been used to show only the presence of the diketone tautomeric form.