Synthése par deux voies différentes d'un systéme dihétérocyclique apparenté aux peltogynoides

5-Oxo-5H,7H-[2]benzopyrano[4,3-b][1]benzopyran ( 2 ) has been synthesized from 3-(o-hydroxybenzylidene)isochroman-1,4-dione ( 3 ) by reductive cyclization, and from 5H,7H[2]benzo-pyrano[4,3-b][1]benzopyran-5,7-dione ( 4 ) by selective hydro-genation. This second method affords the dihydro compound 6 or 6a,12a-dihydro-5H,7H-[2]benzopyrano[4,3-b] [1 ]benzopyran-5-one as reaction time increases.     

Le diméthyl- et le diéthyl-tétracarbonylosmium Synthèse et réactivité

The sodium salt Na₂[Os(CO)₄] has been obtained in high yields by the reduction of either OsH₂(CO)₄ or Os₃(CO)₁₂ with sodium sand in the presence of catalytic amounts of 2, 2′-bipyridyle. The reaction of Na₂[Os(CO)₄] with alkylating agents such as methyl and ethyl iodide produces OsR₂(CO)₄ (R = CH₃, C₂H₅). NMR. and IR. spectra indicate a cis-octahedral structure of symmetry C_2v for these new alkyl compounds. Bromine breaks one osmium-carbon bond in cis-Os(CH₃)₂(CO)₄ to give cis-OsCH₃Br(CO)₄, whereas in cis-Os(C₂H₅)₂(CO)₄ both ethyl groups are easily displaced by bromine to give cis-OsBr₂(CO)₄. Under CO pressure and at elevated temperature cis-Os(CH₃)₂(CO)₄ is converted to Os(CO)₅ and ethane. With cis-Os(C₂H₅)₂(CO)₄ two CO are inserted in osmium-carbon bonds to give . NMR. and IR. data suggest a cis-configuration for this derivative and the possibility of the presence of rotational isomers.     

Thiényl- et séléniénylthiocyanates et sélénocyanates. 4. Synthèses de thiéno[2,3-d]thiazoles,de thiéno[2,3-e]thiazines et de quelques analogues sélénophéniques

Nucleophilic aromatic substitution of 3-bromo-2nitrothiophene and selenophene by thiocyanate and selenocyanate ions in dimethylsulfoxide yields 3-thienyl-and 3-selenienylthicoyanates and selenocyanates. After reduction of the nitro group, the amino derivatives undergo cyclizatrion to thieno[2,3-d]thiazoles and seleno [2,3-d]thiazoles. Also, 4H-2,3-dihydro-3-oxothieno[2,3-e]1,4-thiazine and its selenophene analog have been obtained.     

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.     

Réactivité d'analogues bihétérocycliques du phénanthrène,vis-à-vis des agents d'acétylation et de lithiation

The influence of annelaction and of the heteroatom upon the reactity of some haterocyclic analogus of phenanthrene with a pyrrole nucleos was tested toward acetylation and lithiation. If methy-l[1]benzofuro-[3,2-b]pyrrole was acetylated only in the 2-position, the sulfer and selenious analogues with [3,2-b] and [2,3-b] annelarion were acetylated in the -2 and -3 position. No reaction at all or only with poor yield (in the oxygenated series) was observed with butyllithium except on the case of l-methyl[1]benzoselenono[2,3-b]pyrrole, where the opening of the selenophene nucleos gives, after carbonation and action of diazomethane, l-methyl-2-methoxycarbony 1-3-(o-methylselenophenyl) pyrrole.     

Déconjugaison d'énones dérivées de sucres Communication préliminaire

Deconjugation of sugars enones. Preliminary Communication Branched-chain sugar enones 1 and 2 ( R = Ac) deconjugated toposelectively (only the E isomers reacting) to 3 . The same phenomenon was noted in the case of Z- 4 which gave E- 5 . The kinetic parameters of these reactions favored a concerted mechanism, i.e. a [1, 5]-sigmatropic shift.     

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.     

Interactions intramoléculaires. XXVI—Constantes de couplage et hétérogénéités conformationnelles dans une série de R-3 et R-5 cyano-4 cyclohexènes deutériés (R=méthyl ou t-butyl)

For trans-3-R- and 5-R-1-acetoxy-4-cyanocyclohexene-6,6-d₂ the molar fractions of diequatorial conformers are 0.83 (3-methyl), 0.68 (5-methyl), 0.57 (3-tert-butyl) and 0.55–0.69 (5-tert-butyl). For the last two compounds the values of the coupling constants are in agreement with the hypothesis of an ee?aa equilibrium. For the cis isomers, the molar fractions of equatorial alkyl conformers are 0.76 (3-methyl and 5-methyl) and 1.0 (3-tert-butyl and 5-tert-butyl). The cis-1-acetoxy-3-tert-butyl-4-methoxycarbonyl-cyclohexene presents a conformational heterogeneity. The conformational free energy of the methyl group in position 4 has been evaluated as ?0.6 kcal mol^?1 (2.5 kJ mol^?1).     

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.     

Etude Stéréochimique par RMN 1H de Tetrahydropyrannes β-Chlorés α-Substitués

The ¹H NMR study of 2-alkyl-3-chlorotetrahydropyrans, obtained by reaction of Grignard reagents with a mixture of cis/trans-2,3-dichlorotetrahydropyrans, shows cis/trans configuration of two isomers in which the alkyl substituents are exclusively in the equatorial position. 3-Chloro-2-phenyltetrahydropyran exists in trans (eq-eq) configuration only. The ¹H NMR study of cis/trans 2-alkoxy (or aryloxy)-3-chlorotetrahydropyrans, obtained by reaction of alcohols or phenol with 2,3-dichlorotetrahydropyrans, shows the axial position of the alkoxy (or aryloxy) substituent.     

Synthèse de spiro-pyrazolines par cycloaddition du diazométhane sur des sucres insaturés ramifiés. Influence de l'isomérie géométrique sur l'orientation de la réaction Communication préliminaire

The orientation of the cycloaddition of diazomethane on unsaturated branchedchain sugars has been studied. For 3-C-cyanomethylidene-3-deoxy-1,2-O-isopropylidene-α-D-glycero-tetrofuranose the orientation was ‘normal’ and did not depend on the configuration at the double bond. The same situation prevailed with derivatives of 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methylidene-α-D-xylo-hexofuranose. For the 3-C-acylmethylidene- and the 3-C-cyanomethylidene-3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranoses, the trans-(H–C(3′)–C(2))-isomer gave the ‘normal’ cycloadduct whereas the cis-isomer gave predominantly the αabnormal spiro-pyrazoline. This observation represents the first instance where the regioselectivity of a cycloaddition reaction is affected by the geometrical isomerism of the dipolarophile. The most probable explanation of the phenomenon is the conformational perturbation about the C(4)--C(5) bond of the unsaturated sugars induced by a change in the configuration at C(3). The consequence of that ‘conformational transmission’ of a difference in configuration at C(3) is that the steric crowding on the cis- than in the trans-isomer. Several novel examples of a new series of C-glycosylidenic derivatives, the spiro-pyrazolines, are described.     

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.     

Alcoxyflurophosphoranes. II—Monoalcoxyfluorophosphoranes possédant un centre d'asymétrie; diastéréotopie des fluors apicaux

Twenty-six monoalkoxyfluorophosphoranes bearing an asymmetric substituent of types R¹PF₃(OR²*)( 1 ), R¹*PF₃(OR²) ( 2 ), R¹R³PF₂(OR²* 3 ) and R₂¹PF₂(OR²*)( 4 ), have been prepared. The non-equivalence of the axial fluorine atoms is observed in the ¹⁹F NMR spectra for the compounds of types 1 δ_F′a – δ_F′a ～ 0·5 to 3·8 ppm, J(F_aF′_a) ～ 10 Hz, 2 δ_Fa – δ_F′a ～ 1·1 to 1·5 ppm, J(F_aF′_a) ～ 14 Hz and 3 δ_Fa – δ_Fa ～ 0·2 ppm, J(F_aF′_a) ～ 10 Hz but not for those of type 4 R₁²PF₂(OR²*). Its origin is assigned to the diastereotopic character of these fluorines. The possibility of a hindered rotation of the substituents as the origin of the phenomenon is excluded. The preparation of sec-BuPF₄ and EtPhPF₃ is also reported.     

Réactions de Friedel et Crafts de dérivés aromatiques sur les composés dioxo-1,4,2,3-non saturés. IV. Réactions des hydroxy-5-ouchloro-5-diméthyl-3,5- ou diméthyl-4,5-dihydro-2,5-furannones-2

Friedel-Crafts reactions of aromatic derivatives with 1,4-dicarbonyls 2,3-éthylenic compounds. Part IV. Reactions of 5-hydroxy or 5-chloro 3,5-dimethyl or 4,5-dimethyl 2 (5 H) furanones We studied the Friedel-Crafts reactions of 2-(5H)-furanones. In the presence of sulfuric acid and of an aromatic derivative, 5-hydroxy- or 5-chloro-5-methyl-2-(5H)-furanones with one methyl group either in the 3 position, or in the 4 position generally give the corresponding 5-aryl-2-(5H)-furanones, while with aluminium chloride, it is possible to obtain, when a reaction takes place, isomeric 1H-indenecarboxylic acids. However, in a particular case, an addition to the substrate's double bond is observed. The 3-aryl-5-hydroxy-tetrahydrofuran-2-one obtained is methylated in two ways and gives either a cyclic product, or a linear one. In two cases tautomerism between 1H-1-indenecarboxylic acid and 1H-3-indenecarboxylic has been shown by ¹H-NMR.     

Synthèses dans la série des bis-indéno-fluorènes,IX. Le dihydro-13,15-7H-bis-indéno[2.1-b; 2′.1′-h]fluorène et son dérivé méthylé en position 6

By condensation according Ullmann of 2-iodo-9-oxo-fluorene with 3-bromo-2-cyano-9-oxo-fluorene, followed by cyclisation and reduction, the new linear 13,15-dihydro-7H-diindeno[2.1-b; 2′.1′-h]fluorene (III) is synthesized in 3 steps. The 6-methyl-derivative of II is also obtained in a similar way.     

β-Dicéto énamines hététrocycliques: 1. Indanediones-1,3 substituées en 2 par un hétérocycle azoté

The condensation of methylated N-heterocycles and espically monomethyl- and polymethylpyridinets on phthalic enhydrides leads to 2-ary1-1,3-indanediones. The 3alklidenylphthalides formed in an intermediary state have been isloated. The influence of solvents and temperature on the velocity and yeild of formation of 2-(2- and 4-pyridyl)-1,3-indandiobnes has been studies. The ir and nmr spectra confirm taht these compunds exist under a β-diketoenamine form resonating witj a betaine form.     

Fluorénacènes et fluorénaphènes synthèses dans la série des indéno-fluorènes,XVII. Dérivés méthylés du cis-fluorénacène,du trans-fluorénacène et du trans-fluorénaphène

By condensation of the chlorides of the three 9-oxo-fluorene-2-, -3-, and -4-carboxylic acids with 4-bromo-1,2-xylene on one side, and of the chlorides of o-bromobenzoic acid, 2-bromo-4-methyl-benzoic acid and 2-bromo-4,5-dimethyl-benzoic acid with fluorene, 2-methylfluorene and 3-methylfluorene on the other side, followed by direct or indirect cyclisation and by final reduction, several new methyl derivatives of the indenofluorenes I, II and IV are synthesized.     

Application de la réaction de Wittig à la synthèse de dérivés de bromoénosuloses et d'esters bromoénuroniques. Note de laboratoire

Use of the Wittig reaction for the synthesis of derivatives of bromoenosuloses and bromoenuronic esters Treatment of 3-O-benzyl (or 3-O-methyl)-1, 2-O-isopropylidene-α-D -xylo-pentodialdo-1, 4-furanoses ( 2 or 1 ) with acetylbromomethylidenetriphenylphosphorane ( 3 ), benzoylbromomethylidenetriphenylphosphorane ( 4 ) or bromoethoxycarbonylmethylidenetriphenylphosphorane ( 5 ) gave in good to excellent yields the expected enose ( 6--11 ). In all cases but one ( 8 where some 10% of the E-isomer was formed) the reaction led to the exclusive formation of the Z-isomer whose configuration was established by NMR.     

Préparation de phosphonates de sucres ramifiés par addition nucléophile conjuguée. Communication préliminaire

Preparation of unsaturated sugars phosphonates using nucleophilic conjugate addition Different types of phosphorus nucleophiles underwent conjugate addition reaction with one of the branched-chain sugars 4, 5 or 11 the addition taking place either on the endo or the exo face of the furanose ring (or on both faces in the case of 11 ). The configuration at C(3) of these new phosphorus-bearing types of sugars as well as the configuration at the phosphorus atom of the cyclic phosphinates 9 and 10 was established by NMR. (³J_P,H–C(2), ³J_P,C(1)). Small amounts (7%) of the spiro enol phosphonate 16 were formed when 11 reacted with trimethyl phosphite.     

Couplages J des groupes méthyle dans les phényltriméthylsilanes p-substitués: Effets de solvants

The J coupling constants of a series of p-substituted phenyltrimethylsilanes were measured in CH₂Cl₂ and CCl₄ solutions. The solvent effect is discussed; it is too large to allow any straightward conclusion on ring-substituent interaction.