Synthese de cetones aliphatiques encombrees : Action des organolithiens sur les dimethyl-4,4 oxazolines-2. Addition des organometalliques sur les sels de dimethyl-4,4 oxazolinium-2

α,α-Disubstituted ketones result from the reaction of organolithium compounds with substituted 4,4-dimethyl-2-oxazolines, 4, after hydrolysis of the intermediate enamine. Alkylation of the latter also permits the synthesis of α,α,α-trisubstituted ketones. α,α-Disubstituted ketones have been prepared by addition of organometallic reagents to 4,4-dimethyl-2-oxazolinium salts, 6. The efficiency of this method has been compared to that of other currently used methods.     

Composes organiques du phosphore XIII (1) apercu sur les sels de phosphonium di- et tri-acetyleniques. Nouvelle methode de synthese de sels de phosphonia-4-pyrannes.

In opposition to the di- and tri-acetylenic phosphonium salts bearing phenylethynyl groups which are readily hydrolyzed, phosphonium salts bearing two tert-butylethynyl groups are quite stable in the presence of water.With acetic acid in presence of ammonium acetate, these cations add one molecule of water and yield the 4-phosphoniapyrane salts instead of the corresponding nitrogen heterocycles.     

Addition nucleophile des anions d'esters α-cyanoacetiques sur les cations succinimidosulfonium: Fragmentation ionique ou radicalaire des′ σ-sulfuranes intermediaires

Reactions of substituted cyanoacetate anions 4 with S,S-dialayklsuccinimidosulfonium salts resulted generally in the formation of N-alkylthiomethylketenimines and α-alkylthiomethylesters. Coupling products were also obtained with anion 4d and only observed in the case of methyl phenylcyanoacetate anion 4b. The results were interpreted by the formation of instable σ-sulfurane intermediates. Homolytic cleavage of these intermediates gave radical pairs, then the coupling products. Heterocyclic clevage gave new sulfonium salts which rearranged via sulfonium ylides.     

Addition conjuguee des α, ω-bis(bromomagnesio)alcanes sur les coumarines

Reactions of 1,4-bis(bromomagnesio)bütane and 1,5-bis(bromomagnesio) pentane with coumarin and 6-methylcoumarin gave a mixture of 1-(o-hydroxystyryl)cycloalkanol and 4-alkyl-3,4-dihydrocoumarin. A large difference in product distribution was observed between the two bifunctional reagents. Annelation was favored by the use of 1,4-bis(bromomagnesio))butane, whereas conjugate addition was observed with 1,5-bis(bromomagnesio)pentane and even In the use of 4-methylcoumarin.     

Dienophilie des cyano-1 enamines,nouveaux equivalents de cetenes pour les cycloadditions de diels-alder1

The Diels-Alder reactivity of two captodative olefins, 2-morpho-lino-acrylonitrile $\text{15}$ and 2-(N-methlanilino) -acrylonitrile $\text{16}$, towards four conjugated dienes is evaluated.In every cases, isomeric {4+2} cyclo-adducts are obtained.With olefin $\text{15}$ yields are better than with olefin $\text{16}$. The adducts are easily transformed in to the corresponding ketones by a mild hydrolysis of the α-aminonitrile group. Thus, the 1-cyanoenamines can be considered as good ketene equivalents very useful for the synthesis of unsaturated cyclohexanones.     

Reaction des lithiens avec les organophosphores. Reaction d'addition du t-butyllithium sur le noyau benzenique des sels de phenylphosphoniums

A new reaction of organolithium compounds with phosphonium salts is described; reaction of t-butyllithium with dibenzylaminophosphonium or tetraphenylphosphonium bromides takes place through addition of the t-butyl group on a benzene ring at the position para to the phosphorus atom, the ylid formed reacts in a characteristic Wittig reaction with p-tolylaldehyde.     

Etude par RMN du mecanisme des reactions de transcomplexation entre les sels de chloroiminium (reactifs de vilsmeier) et les amides ou thioamides. Appl

Previous studies have established the existence of an acid-base equilibrium between the Vilsmeier complex (Me₂NCHCl)⁺ B^? and dimethylformamide. It is shown that the behaviour of chloroiminium salts as Lewis acids towards amides or thioamides is a general phenomenon. When the acids and bases are differently substituted, the reaction may have synthetic applications.     

Synthese de 2h-pyrroles et de pyrroles: action de carbanions sur des 2H-azirines ou des sels de N,N,N-trimethylhydrazonium

Dimsyl sodium reacts with 2H-azirines 2 to give amino ethylenic sulfoxide 5E. The same reaction is observed from N,N,N-trimethylhydrazonium salt 1 using an excess of dimsylsodium. Carbanions of ketone or nitrile react with 2H-azirine or N,N,N-trimethylhydrazonium to produce 2H-pyrroles 6–13, 20 or pyrroles 18, 19. This reaction is the most convenient general route to 2H-pyrroles.     

Action des reactifs de grignard sur les dithioesters : Addition carbophile d'organomagnesiens insatures. synthese de cetones β-ethyleniques

Reactions of allyl, benzyl, propargyl and vinyl Grignard reagents with methyl dithioacetate give dithioacetals (or hemidithioacetals) resulting from a carbophilic addition process. Reactions with various allylic organomagnesium compounds always involve an “inversion” of the allylic chain and direct carbophilic addition, rather than initial thiophilic addition followed by [2.3] sigmatropic shift. Three methods for the synthesis of β-unsaturated ketones are described, showing the potential synthetic uses of the reactions of Grignard reagents with dithioesters.     

L'action de l'ammoniac sur l'oxyde cuivrique. et les hydroxo-complexes de cuivre (II)

Using a new mathematical treatment, the nature and stability constants of the simple and mixed complex-species of copper(II) with hydroxyde and ammonia as ligands have been determined. The solubility curves of CuO in heterogeneous equilibrium have been identified in function of pH only and in function of pH and pNH_3tot at 25° and unit ionic strength (NaClO₄). The predominent species in the relatively dilute system limited by the ionic strength are [Cu²⁺], [Cu(OH)₂], [Cu(OH)], [Cu(OH)], [Cu(NH₃)], [Cu(NH₃)], [Cu(NH₃)], [Cu(NH₃) (OH)⁺], [Cu(NH₃)₃(OH)⁺] and [Cu(NH₃)₂(OH)₂].     

Action des derives du phosphore trivalent sur les composes a halogene positif—VII : Cycloaddition avec les sels d'(α-cetoceteniminyl) phosphonium

The reaction of phosphines (Ph₃P, (pMeC₆H₄)₃P) with α-cyano α-haloimides gives, by attack on halogen, an ion-pair, which rearranges into a (α-ketoketeniminyl)phosphonium salt. When P(NMe₂)₃ is used, the nucleophilic attack of the anion O-atom at the halophosphonium cation-P atom is also observed. The α-ketoketeniminyl phosphonium salts give α-haloiminophosphoranes or oxazines by cycloaddition with the anion of the ion pair.     

Action des isocyanates sur les benzisothiazol-2,1 ones-3 (1H) et sur les thiadiazol-1,2,4 ones-5: Un nouveau réarrangement avec extrusion de l'atome de soufre

The reaction of isocyanates with 2,1-benzisothiazo1-3-(1H)ones and on 1,2,4-thiadiazo1-5-(4H)ones was investigated. With a stoichiometric amount of organic base the reaction resulted, in both cases, in the incorporation of two atoms of the isocyanate into the heterocycle and concomitant extrusion of the sulphur atom.